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0dfc852b6fe3cbecbea67332a0dce2bebeba540d
5927 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Randy Dunlap
|
7beb82b7d5 |
tracing/synthetic: fix kernel-doc warnings
scripts/kernel-doc warns about using @args: for variadic arguments to functions. Documentation/doc-guide/kernel-doc.rst says that this should be written as @...: instead, so update the source code to match that, preventing the warnings. trace_events_synth.c:1165: warning: Excess function parameter 'args' description in '__synth_event_gen_cmd_start' trace_events_synth.c:1714: warning: Excess function parameter 'args' description in 'synth_event_trace' Link: https://lore.kernel.org/linux-trace-kernel/20231220061226.30962-1-rdunlap@infradead.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Fixes: |
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|
Steven Rostedt (Google)
|
b803d7c664 |
ring-buffer: Fix slowpath of interrupted event
To synchronize the timestamps with the ring buffer reservation, there are
two timestamps that are saved in the buffer meta data.
1. before_stamp
2. write_stamp
When the two are equal, the write_stamp is considered valid, as in, it may
be used to calculate the delta of the next event as the write_stamp is the
timestamp of the previous reserved event on the buffer.
This is done by the following:
/*A*/ w = current position on the ring buffer
before = before_stamp
after = write_stamp
ts = read current timestamp
if (before != after) {
write_stamp is not valid, force adding an absolute
timestamp.
}
/*B*/ before_stamp = ts
/*C*/ write = local_add_return(event length, position on ring buffer)
if (w == write - event length) {
/* Nothing interrupted between A and C */
/*E*/ write_stamp = ts;
delta = ts - after
/*
* If nothing interrupted again,
* before_stamp == write_stamp and write_stamp
* can be used to calculate the delta for
* events that come in after this one.
*/
} else {
/*
* The slow path!
* Was interrupted between A and C.
*/
This is the place that there's a bug. We currently have:
after = write_stamp
ts = read current timestamp
/*F*/ if (write == current position on the ring buffer &&
after < ts && cmpxchg(write_stamp, after, ts)) {
delta = ts - after;
} else {
delta = 0;
}
The assumption is that if the current position on the ring buffer hasn't
moved between C and F, then it also was not interrupted, and that the last
event written has a timestamp that matches the write_stamp. That is the
write_stamp is valid.
But this may not be the case:
If a task context event was interrupted by softirq between B and C.
And the softirq wrote an event that got interrupted by a hard irq between
C and E.
and the hard irq wrote an event (does not need to be interrupted)
We have:
/*B*/ before_stamp = ts of normal context
---> interrupted by softirq
/*B*/ before_stamp = ts of softirq context
---> interrupted by hardirq
/*B*/ before_stamp = ts of hard irq context
/*E*/ write_stamp = ts of hard irq context
/* matches and write_stamp valid */
<----
/*E*/ write_stamp = ts of softirq context
/* No longer matches before_stamp, write_stamp is not valid! */
<---
w != write - length, go to slow path
// Right now the order of events in the ring buffer is:
//
// |-- softirq event --|-- hard irq event --|-- normal context event --|
//
after = write_stamp (this is the ts of softirq)
ts = read current timestamp
if (write == current position on the ring buffer [true] &&
after < ts [true] && cmpxchg(write_stamp, after, ts) [true]) {
delta = ts - after [Wrong!]
The delta is to be between the hard irq event and the normal context
event, but the above logic made the delta between the softirq event and
the normal context event, where the hard irq event is between the two. This
will shift all the remaining event timestamps on the sub-buffer
incorrectly.
The write_stamp is only valid if it matches the before_stamp. The cmpxchg
does nothing to help this.
Instead, the following logic can be done to fix this:
before = before_stamp
ts = read current timestamp
before_stamp = ts
after = write_stamp
if (write == current position on the ring buffer &&
after == before && after < ts) {
delta = ts - after
} else {
delta = 0;
}
The above will only use the write_stamp if it still matches before_stamp
and was tested to not have changed since C.
As a bonus, with this logic we do not need any 64-bit cmpxchg() at all!
This means the 32-bit rb_time_t workaround can finally be removed. But
that's for a later time.
Link: https://lore.kernel.org/linux-trace-kernel/20231218175229.58ec3daf@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20231218230712.3a76b081@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Fixes:
|
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|
Steven Rostedt (Google)
|
712292308a |
ring-buffer: Do not record in NMI if the arch does not support cmpxchg in NMI
As the ring buffer recording requires cmpxchg() to work, if the architecture does not support cmpxchg in NMI, then do not do any recording within an NMI. Link: https://lore.kernel.org/linux-trace-kernel/20231213175403.6fc18540@gandalf.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> |
||
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Steven Rostedt (Google)
|
0aa0e5289c |
ring-buffer: Have rb_time_cmpxchg() set the msb counter too
The rb_time_cmpxchg() on 32-bit architectures requires setting three
32-bit words to represent the 64-bit timestamp, with some salt for
synchronization. Those are: msb, top, and bottom
The issue is, the rb_time_cmpxchg() did not properly salt the msb portion,
and the msb that was written was stale.
Link: https://lore.kernel.org/linux-trace-kernel/20231215084114.20899342@rorschach.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes:
|
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|
Mathieu Desnoyers
|
dec890089b |
ring-buffer: Fix 32-bit rb_time_read() race with rb_time_cmpxchg()
The following race can cause rb_time_read() to observe a corrupted time
stamp:
rb_time_cmpxchg()
[...]
if (!rb_time_read_cmpxchg(&t->msb, msb, msb2))
return false;
if (!rb_time_read_cmpxchg(&t->top, top, top2))
return false;
<interrupted before updating bottom>
__rb_time_read()
[...]
do {
c = local_read(&t->cnt);
top = local_read(&t->top);
bottom = local_read(&t->bottom);
msb = local_read(&t->msb);
} while (c != local_read(&t->cnt));
*cnt = rb_time_cnt(top);
/* If top and msb counts don't match, this interrupted a write */
if (*cnt != rb_time_cnt(msb))
return false;
^ this check fails to catch that "bottom" is still not updated.
So the old "bottom" value is returned, which is wrong.
Fix this by checking that all three of msb, top, and bottom 2-bit cnt
values match.
The reason to favor checking all three fields over requiring a specific
update order for both rb_time_set() and rb_time_cmpxchg() is because
checking all three fields is more robust to handle partial failures of
rb_time_cmpxchg() when interrupted by nested rb_time_set().
Link: https://lore.kernel.org/lkml/20231211201324.652870-1-mathieu.desnoyers@efficios.com/
Link: https://lore.kernel.org/linux-trace-kernel/20231212193049.680122-1-mathieu.desnoyers@efficios.com
Fixes:
|
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|
Steven Rostedt (Google)
|
fff88fa0fb |
ring-buffer: Fix a race in rb_time_cmpxchg() for 32 bit archs
Mathieu Desnoyers pointed out an issue in the rb_time_cmpxchg() for 32 bit
architectures. That is:
static bool rb_time_cmpxchg(rb_time_t *t, u64 expect, u64 set)
{
unsigned long cnt, top, bottom, msb;
unsigned long cnt2, top2, bottom2, msb2;
u64 val;
/* The cmpxchg always fails if it interrupted an update */
if (!__rb_time_read(t, &val, &cnt2))
return false;
if (val != expect)
return false;
<<<< interrupted here!
cnt = local_read(&t->cnt);
The problem is that the synchronization counter in the rb_time_t is read
*after* the value of the timestamp is read. That means if an interrupt
were to come in between the value being read and the counter being read,
it can change the value and the counter and the interrupted process would
be clueless about it!
The counter needs to be read first and then the value. That way it is easy
to tell if the value is stale or not. If the counter hasn't been updated,
then the value is still good.
Link: https://lore.kernel.org/linux-trace-kernel/20231211201324.652870-1-mathieu.desnoyers@efficios.com/
Link: https://lore.kernel.org/linux-trace-kernel/20231212115301.7a9c9a64@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes:
|
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|
Steven Rostedt (Google)
|
083e9f65bd |
ring-buffer: Remove useless update to write_stamp in rb_try_to_discard()
When filtering is enabled, a temporary buffer is created to place the
content of the trace event output so that the filter logic can decide
from the trace event output if the trace event should be filtered out or
not. If it is to be filtered out, the content in the temporary buffer is
simply discarded, otherwise it is written into the trace buffer.
But if an interrupt were to come in while a previous event was using that
temporary buffer, the event written by the interrupt would actually go
into the ring buffer itself to prevent corrupting the data on the
temporary buffer. If the event is to be filtered out, the event in the
ring buffer is discarded, or if it fails to discard because another event
were to have already come in, it is turned into padding.
The update to the write_stamp in the rb_try_to_discard() happens after a
fix was made to force the next event after the discard to use an absolute
timestamp by setting the before_stamp to zero so it does not match the
write_stamp (which causes an event to use the absolute timestamp).
But there's an effort in rb_try_to_discard() to put back the write_stamp
to what it was before the event was added. But this is useless and
wasteful because nothing is going to be using that write_stamp for
calculations as it still will not match the before_stamp.
Remove this useless update, and in doing so, we remove another
cmpxchg64()!
Also update the comments to reflect this change as well as remove some
extra white space in another comment.
Link: https://lore.kernel.org/linux-trace-kernel/20231215081810.1f4f38fe@rorschach.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Fixes:
|
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|
Steven Rostedt (Google)
|
dd93942570 |
ring-buffer: Do not try to put back write_stamp
If an update to an event is interrupted by another event between the time
the initial event allocated its buffer and where it wrote to the
write_stamp, the code try to reset the write stamp back to the what it had
just overwritten. It knows that it was overwritten via checking the
before_stamp, and if it didn't match what it wrote to the before_stamp
before it allocated its space, it knows it was overwritten.
To put back the write_stamp, it uses the before_stamp it read. The problem
here is that by writing the before_stamp to the write_stamp it makes the
two equal again, which means that the write_stamp can be considered valid
as the last timestamp written to the ring buffer. But this is not
necessarily true. The event that interrupted the event could have been
interrupted in a way that it was interrupted as well, and can end up
leaving with an invalid write_stamp. But if this happens and returns to
this context that uses the before_stamp to update the write_stamp again,
it can possibly incorrectly make it valid, causing later events to have in
correct time stamps.
As it is OK to leave this function with an invalid write_stamp (one that
doesn't match the before_stamp), there's no reason to try to make it valid
again in this case. If this race happens, then just leave with the invalid
write_stamp and the next event to come along will just add a absolute
timestamp and validate everything again.
Bonus points: This gets rid of another cmpxchg64!
Link: https://lore.kernel.org/linux-trace-kernel/20231214222921.193037a7@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Fixes:
|
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|
Zheng Yejian
|
1cc111b9cd |
tracing: Fix uaf issue when open the hist or hist_debug file
KASAN report following issue. The root cause is when opening 'hist'
file of an instance and accessing 'trace_event_file' in hist_show(),
but 'trace_event_file' has been freed due to the instance being removed.
'hist_debug' file has the same problem. To fix it, call
tracing_{open,release}_file_tr() in file_operations callback to have
the ref count and avoid 'trace_event_file' being freed.
BUG: KASAN: slab-use-after-free in hist_show+0x11e0/0x1278
Read of size 8 at addr ffff242541e336b8 by task head/190
CPU: 4 PID: 190 Comm: head Not tainted 6.7.0-rc5-g26aff849438c #133
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x98/0xf8
show_stack+0x1c/0x30
dump_stack_lvl+0x44/0x58
print_report+0xf0/0x5a0
kasan_report+0x80/0xc0
__asan_report_load8_noabort+0x1c/0x28
hist_show+0x11e0/0x1278
seq_read_iter+0x344/0xd78
seq_read+0x128/0x1c0
vfs_read+0x198/0x6c8
ksys_read+0xf4/0x1e0
__arm64_sys_read+0x70/0xa8
invoke_syscall+0x70/0x260
el0_svc_common.constprop.0+0xb0/0x280
do_el0_svc+0x44/0x60
el0_svc+0x34/0x68
el0t_64_sync_handler+0xb8/0xc0
el0t_64_sync+0x168/0x170
Allocated by task 188:
kasan_save_stack+0x28/0x50
kasan_set_track+0x28/0x38
kasan_save_alloc_info+0x20/0x30
__kasan_slab_alloc+0x6c/0x80
kmem_cache_alloc+0x15c/0x4a8
trace_create_new_event+0x84/0x348
__trace_add_new_event+0x18/0x88
event_trace_add_tracer+0xc4/0x1a0
trace_array_create_dir+0x6c/0x100
trace_array_create+0x2e8/0x568
instance_mkdir+0x48/0x80
tracefs_syscall_mkdir+0x90/0xe8
vfs_mkdir+0x3c4/0x610
do_mkdirat+0x144/0x200
__arm64_sys_mkdirat+0x8c/0xc0
invoke_syscall+0x70/0x260
el0_svc_common.constprop.0+0xb0/0x280
do_el0_svc+0x44/0x60
el0_svc+0x34/0x68
el0t_64_sync_handler+0xb8/0xc0
el0t_64_sync+0x168/0x170
Freed by task 191:
kasan_save_stack+0x28/0x50
kasan_set_track+0x28/0x38
kasan_save_free_info+0x34/0x58
__kasan_slab_free+0xe4/0x158
kmem_cache_free+0x19c/0x508
event_file_put+0xa0/0x120
remove_event_file_dir+0x180/0x320
event_trace_del_tracer+0xb0/0x180
__remove_instance+0x224/0x508
instance_rmdir+0x44/0x78
tracefs_syscall_rmdir+0xbc/0x140
vfs_rmdir+0x1cc/0x4c8
do_rmdir+0x220/0x2b8
__arm64_sys_unlinkat+0xc0/0x100
invoke_syscall+0x70/0x260
el0_svc_common.constprop.0+0xb0/0x280
do_el0_svc+0x44/0x60
el0_svc+0x34/0x68
el0t_64_sync_handler+0xb8/0xc0
el0t_64_sync+0x168/0x170
Link: https://lore.kernel.org/linux-trace-kernel/20231214012153.676155-1-zhengyejian1@huawei.com
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
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Steven Rostedt (Google)
|
60be76eeab |
tracing: Add size check when printing trace_marker output
If for some reason the trace_marker write does not have a nul byte for the string, it will overflow the print: trace_seq_printf(s, ": %s", field->buf); The field->buf could be missing the nul byte. To prevent overflow, add the max size that the buf can be by using the event size and the field location. int max = iter->ent_size - offsetof(struct print_entry, buf); trace_seq_printf(s, ": %*.s", max, field->buf); Link: https://lore.kernel.org/linux-trace-kernel/20231212084444.4619b8ce@gandalf.local.home Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> |
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Steven Rostedt (Google)
|
b049525855 |
ring-buffer: Have saved event hold the entire event
For the ring buffer iterator (non-consuming read), the event needs to be
copied into the iterator buffer to make sure that a writer does not
overwrite it while the user is reading it. If a write happens during the
copy, the buffer is simply discarded.
But the temp buffer itself was not big enough. The allocation of the
buffer was only BUF_MAX_DATA_SIZE, which is the maximum data size that can
be passed into the ring buffer and saved. But the temp buffer needs to
hold the meta data as well. That would be BUF_PAGE_SIZE and not
BUF_MAX_DATA_SIZE.
Link: https://lore.kernel.org/linux-trace-kernel/20231212072558.61f76493@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes:
|
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|
Steven Rostedt (Google)
|
9e45e39dc2 |
ring-buffer: Do not update before stamp when switching sub-buffers
The ring buffer timestamps are synchronized by two timestamp placeholders.
One is the "before_stamp" and the other is the "write_stamp" (sometimes
referred to as the "after stamp" but only in the comments. These two
stamps are key to knowing how to handle nested events coming in with a
lockless system.
When moving across sub-buffers, the before stamp is updated but the write
stamp is not. There's an effort to put back the before stamp to something
that seems logical in case there's nested events. But as the current event
is about to cross sub-buffers, and so will any new nested event that happens,
updating the before stamp is useless, and could even introduce new race
conditions.
The first event on a sub-buffer simply uses the sub-buffer's timestamp
and keeps a "delta" of zero. The "before_stamp" and "write_stamp" are not
used in the algorithm in this case. There's no reason to try to fix the
before_stamp when this happens.
As a bonus, it removes a cmpxchg() when crossing sub-buffers!
Link: https://lore.kernel.org/linux-trace-kernel/20231211114420.36dde01b@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes:
|
||
|
Steven Rostedt (Google)
|
d06aff1cb1 |
tracing: Update snapshot buffer on resize if it is allocated
The snapshot buffer is to mimic the main buffer so that when a snapshot is
needed, the snapshot and main buffer are swapped. When the snapshot buffer
is allocated, it is set to the minimal size that the ring buffer may be at
and still functional. When it is allocated it becomes the same size as the
main ring buffer, and when the main ring buffer changes in size, it should
do.
Currently, the resize only updates the snapshot buffer if it's used by the
current tracer (ie. the preemptirqsoff tracer). But it needs to be updated
anytime it is allocated.
When changing the size of the main buffer, instead of looking to see if
the current tracer is utilizing the snapshot buffer, just check if it is
allocated to know if it should be updated or not.
Also fix typo in comment just above the code change.
Link: https://lore.kernel.org/linux-trace-kernel/20231210225447.48476a6a@rorschach.local.home
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes:
|
||
|
Steven Rostedt (Google)
|
17d8017581 |
ring-buffer: Fix memory leak of free page
Reading the ring buffer does a swap of a sub-buffer within the ring buffer
with a empty sub-buffer. This allows the reader to have full access to the
content of the sub-buffer that was swapped out without having to worry
about contention with the writer.
The readers call ring_buffer_alloc_read_page() to allocate a page that
will be used to swap with the ring buffer. When the code is finished with
the reader page, it calls ring_buffer_free_read_page(). Instead of freeing
the page, it stores it as a spare. Then next call to
ring_buffer_alloc_read_page() will return this spare instead of calling
into the memory management system to allocate a new page.
Unfortunately, on freeing of the ring buffer, this spare page is not
freed, and causes a memory leak.
Link: https://lore.kernel.org/linux-trace-kernel/20231210221250.7b9cc83c@rorschach.local.home
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes:
|
||
|
Steven Rostedt (Google)
|
b55b0a0d7c |
tracing: Have large events show up as '[LINE TOO BIG]' instead of nothing
If a large event was added to the ring buffer that is larger than what the
trace_seq can handle, it just drops the output:
~# cat /sys/kernel/tracing/trace
# tracer: nop
#
# entries-in-buffer/entries-written: 2/2 #P:8
#
# _-----=> irqs-off/BH-disabled
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / _-=> migrate-disable
# |||| / delay
# TASK-PID CPU# ||||| TIMESTAMP FUNCTION
# | | | ||||| | |
<...>-859 [001] ..... 141.118951: tracing_mark_write <...>-859 [001] ..... 141.148201: tracing_mark_write: 78901234
Instead, catch this case and add some context:
~# cat /sys/kernel/tracing/trace
# tracer: nop
#
# entries-in-buffer/entries-written: 2/2 #P:8
#
# _-----=> irqs-off/BH-disabled
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / _-=> migrate-disable
# |||| / delay
# TASK-PID CPU# ||||| TIMESTAMP FUNCTION
# | | | ||||| | |
<...>-852 [001] ..... 121.550551: tracing_mark_write[LINE TOO BIG]
<...>-852 [001] ..... 121.550581: tracing_mark_write: 78901234
This now emulates the same output as trace_pipe.
Link: https://lore.kernel.org/linux-trace-kernel/20231209171058.78c1a026@gandalf.local.home
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
||
|
Steven Rostedt (Google)
|
b3ae7b67b8 |
ring-buffer: Fix writing to the buffer with max_data_size
The maximum ring buffer data size is the maximum size of data that can be recorded on the ring buffer. Events must be smaller than the sub buffer data size minus any meta data. This size is checked before trying to allocate from the ring buffer because the allocation assumes that the size will fit on the sub buffer. The maximum size was calculated as the size of a sub buffer page (which is currently PAGE_SIZE minus the sub buffer header) minus the size of the meta data of an individual event. But it missed the possible adding of a time stamp for events that are added long enough apart that the event meta data can't hold the time delta. When an event is added that is greater than the current BUF_MAX_DATA_SIZE minus the size of a time stamp, but still less than or equal to BUF_MAX_DATA_SIZE, the ring buffer would go into an infinite loop, looking for a page that can hold the event. Luckily, there's a check for this loop and after 1000 iterations and a warning is emitted and the ring buffer is disabled. But this should never happen. This can happen when a large event is added first, or after a long period where an absolute timestamp is prefixed to the event, increasing its size by 8 bytes. This passes the check and then goes into the algorithm that causes the infinite loop. For events that are the first event on the sub-buffer, it does not need to add a timestamp, because the sub-buffer itself contains an absolute timestamp, and adding one is redundant. The fix is to check if the event is to be the first event on the sub-buffer, and if it is, then do not add a timestamp. This also fixes 32 bit adding a timestamp when a read of before_stamp or write_stamp is interrupted. There's still no need to add that timestamp if the event is going to be the first event on the sub buffer. Also, if the buffer has "time_stamp_abs" set, then also check if the length plus the timestamp is greater than the BUF_MAX_DATA_SIZE. Link: https://lore.kernel.org/all/20231212104549.58863438@gandalf.local.home/ Link: https://lore.kernel.org/linux-trace-kernel/20231212071837.5fdd6c13@gandalf.local.home Link: https://lore.kernel.org/linux-trace-kernel/20231212111617.39e02849@gandalf.local.home Cc: stable@vger.kernel.org Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Fixes: |
||
|
Steven Rostedt (Google)
|
f458a14534 |
ring-buffer: Test last update in 32bit version of __rb_time_read()
Since 64 bit cmpxchg() is very expensive on 32bit architectures, the
timestamp used by the ring buffer does some interesting tricks to be able
to still have an atomic 64 bit number. It originally just used 60 bits and
broke it up into two 32 bit words where the extra 2 bits were used for
synchronization. But this was not enough for all use cases, and all 64
bits were required.
The 32bit version of the ring buffer timestamp was then broken up into 3
32bit words using the same counter trick. But one update was not done. The
check to see if the read operation was done without interruption only
checked the first two words and not last one (like it had before this
update). Fix it by making sure all three updates happen without
interruption by comparing the initial counter with the last updated
counter.
Link: https://lore.kernel.org/linux-trace-kernel/20231206100050.3100b7bb@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes:
|
||
|
Steven Rostedt (Google)
|
b2dd797543 |
ring-buffer: Force absolute timestamp on discard of event
There's a race where if an event is discarded from the ring buffer and an
interrupt were to happen at that time and insert an event, the time stamp
is still used from the discarded event as an offset. This can screw up the
timings.
If the event is going to be discarded, set the "before_stamp" to zero.
When a new event comes in, it compares the "before_stamp" with the
"write_stamp" and if they are not equal, it will insert an absolute
timestamp. This will prevent the timings from getting out of sync due to
the discarded event.
Link: https://lore.kernel.org/linux-trace-kernel/20231206100244.5130f9b3@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes:
|
||
|
Petr Pavlu
|
c0591b1ccc |
tracing: Fix a possible race when disabling buffered events
Function trace_buffered_event_disable() is responsible for freeing pages
backing buffered events and this process can run concurrently with
trace_event_buffer_lock_reserve().
The following race is currently possible:
* Function trace_buffered_event_disable() is called on CPU 0. It
increments trace_buffered_event_cnt on each CPU and waits via
synchronize_rcu() for each user of trace_buffered_event to complete.
* After synchronize_rcu() is finished, function
trace_buffered_event_disable() has the exclusive access to
trace_buffered_event. All counters trace_buffered_event_cnt are at 1
and all pointers trace_buffered_event are still valid.
* At this point, on a different CPU 1, the execution reaches
trace_event_buffer_lock_reserve(). The function calls
preempt_disable_notrace() and only now enters an RCU read-side
critical section. The function proceeds and reads a still valid
pointer from trace_buffered_event[CPU1] into the local variable
"entry". However, it doesn't yet read trace_buffered_event_cnt[CPU1]
which happens later.
* Function trace_buffered_event_disable() continues. It frees
trace_buffered_event[CPU1] and decrements
trace_buffered_event_cnt[CPU1] back to 0.
* Function trace_event_buffer_lock_reserve() continues. It reads and
increments trace_buffered_event_cnt[CPU1] from 0 to 1. This makes it
believe that it can use the "entry" that it already obtained but the
pointer is now invalid and any access results in a use-after-free.
Fix the problem by making a second synchronize_rcu() call after all
trace_buffered_event values are set to NULL. This waits on all potential
users in trace_event_buffer_lock_reserve() that still read a previous
pointer from trace_buffered_event.
Link: https://lore.kernel.org/all/20231127151248.7232-2-petr.pavlu@suse.com/
Link: https://lkml.kernel.org/r/20231205161736.19663-4-petr.pavlu@suse.com
Cc: stable@vger.kernel.org
Fixes:
|
||
|
Petr Pavlu
|
34209fe83e |
tracing: Fix a warning when allocating buffered events fails
Function trace_buffered_event_disable() produces an unexpected warning
when the previous call to trace_buffered_event_enable() fails to
allocate pages for buffered events.
The situation can occur as follows:
* The counter trace_buffered_event_ref is at 0.
* The soft mode gets enabled for some event and
trace_buffered_event_enable() is called. The function increments
trace_buffered_event_ref to 1 and starts allocating event pages.
* The allocation fails for some page and trace_buffered_event_disable()
is called for cleanup.
* Function trace_buffered_event_disable() decrements
trace_buffered_event_ref back to 0, recognizes that it was the last
use of buffered events and frees all allocated pages.
* The control goes back to trace_buffered_event_enable() which returns.
The caller of trace_buffered_event_enable() has no information that
the function actually failed.
* Some time later, the soft mode is disabled for the same event.
Function trace_buffered_event_disable() is called. It warns on
"WARN_ON_ONCE(!trace_buffered_event_ref)" and returns.
Buffered events are just an optimization and can handle failures. Make
trace_buffered_event_enable() exit on the first failure and left any
cleanup later to when trace_buffered_event_disable() is called.
Link: https://lore.kernel.org/all/20231127151248.7232-2-petr.pavlu@suse.com/
Link: https://lkml.kernel.org/r/20231205161736.19663-3-petr.pavlu@suse.com
Fixes:
|
||
|
Petr Pavlu
|
7fed14f7ac |
tracing: Fix incomplete locking when disabling buffered events
The following warning appears when using buffered events: [ 203.556451] WARNING: CPU: 53 PID: 10220 at kernel/trace/ring_buffer.c:3912 ring_buffer_discard_commit+0x2eb/0x420 [...] [ 203.670690] CPU: 53 PID: 10220 Comm: stress-ng-sysin Tainted: G E 6.7.0-rc2-default #4 56e6d0fcf5581e6e51eaaecbdaec2a2338c80f3a [ 203.670704] Hardware name: Intel Corp. GROVEPORT/GROVEPORT, BIOS GVPRCRB1.86B.0016.D04.1705030402 05/03/2017 [ 203.670709] RIP: 0010:ring_buffer_discard_commit+0x2eb/0x420 [ 203.735721] Code: 4c 8b 4a 50 48 8b 42 48 49 39 c1 0f 84 b3 00 00 00 49 83 e8 01 75 b1 48 8b 42 10 f0 ff 40 08 0f 0b e9 fc fe ff ff f0 ff 47 08 <0f> 0b e9 77 fd ff ff 48 8b 42 10 f0 ff 40 08 0f 0b e9 f5 fe ff ff [ 203.735734] RSP: 0018:ffffb4ae4f7b7d80 EFLAGS: 00010202 [ 203.735745] RAX: 0000000000000000 RBX: ffffb4ae4f7b7de0 RCX: ffff8ac10662c000 [ 203.735754] RDX: ffff8ac0c750be00 RSI: ffff8ac10662c000 RDI: ffff8ac0c004d400 [ 203.781832] RBP: ffff8ac0c039cea0 R08: 0000000000000000 R09: 0000000000000000 [ 203.781839] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 203.781842] R13: ffff8ac10662c000 R14: ffff8ac0c004d400 R15: ffff8ac10662c008 [ 203.781846] FS: 00007f4cd8a67740(0000) GS:ffff8ad798880000(0000) knlGS:0000000000000000 [ 203.781851] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 203.781855] CR2: 0000559766a74028 CR3: 00000001804c4000 CR4: 00000000001506f0 [ 203.781862] Call Trace: [ 203.781870] <TASK> [ 203.851949] trace_event_buffer_commit+0x1ea/0x250 [ 203.851967] trace_event_raw_event_sys_enter+0x83/0xe0 [ 203.851983] syscall_trace_enter.isra.0+0x182/0x1a0 [ 203.851990] do_syscall_64+0x3a/0xe0 [ 203.852075] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 203.852090] RIP: 0033:0x7f4cd870fa77 [ 203.982920] Code: 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 90 b8 89 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e9 43 0e 00 f7 d8 64 89 01 48 [ 203.982932] RSP: 002b:00007fff99717dd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000089 [ 203.982942] RAX: ffffffffffffffda RBX: 0000558ea1d7b6f0 RCX: 00007f4cd870fa77 [ 203.982948] RDX: 0000000000000000 RSI: 00007fff99717de0 RDI: 0000558ea1d7b6f0 [ 203.982957] RBP: 00007fff99717de0 R08: 00007fff997180e0 R09: 00007fff997180e0 [ 203.982962] R10: 00007fff997180e0 R11: 0000000000000246 R12: 00007fff99717f40 [ 204.049239] R13: 00007fff99718590 R14: 0000558e9f2127a8 R15: 00007fff997180b0 [ 204.049256] </TASK> For instance, it can be triggered by running these two commands in parallel: $ while true; do echo hist:key=id.syscall:val=hitcount > \ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger; done $ stress-ng --sysinfo $(nproc) The warning indicates that the current ring_buffer_per_cpu is not in the committing state. It happens because the active ring_buffer_event doesn't actually come from the ring_buffer_per_cpu but is allocated from trace_buffered_event. The bug is in function trace_buffered_event_disable() where the following normally happens: * The code invokes disable_trace_buffered_event() via smp_call_function_many() and follows it by synchronize_rcu(). This increments the per-CPU variable trace_buffered_event_cnt on each target CPU and grants trace_buffered_event_disable() the exclusive access to the per-CPU variable trace_buffered_event. * Maintenance is performed on trace_buffered_event, all per-CPU event buffers get freed. * The code invokes enable_trace_buffered_event() via smp_call_function_many(). This decrements trace_buffered_event_cnt and releases the access to trace_buffered_event. A problem is that smp_call_function_many() runs a given function on all target CPUs except on the current one. The following can then occur: * Task X executing trace_buffered_event_disable() runs on CPU 0. * The control reaches synchronize_rcu() and the task gets rescheduled on another CPU 1. * The RCU synchronization finishes. At this point, trace_buffered_event_disable() has the exclusive access to all trace_buffered_event variables except trace_buffered_event[CPU0] because trace_buffered_event_cnt[CPU0] is never incremented and if the buffer is currently unused, remains set to 0. * A different task Y is scheduled on CPU 0 and hits a trace event. The code in trace_event_buffer_lock_reserve() sees that trace_buffered_event_cnt[CPU0] is set to 0 and decides the use the buffer provided by trace_buffered_event[CPU0]. * Task X continues its execution in trace_buffered_event_disable(). The code incorrectly frees the event buffer pointed by trace_buffered_event[CPU0] and resets the variable to NULL. * Task Y writes event data to the now freed buffer and later detects the created inconsistency. The issue is observable since commit |
||
|
Steven Rostedt (Google)
|
b538bf7d0e |
tracing: Disable snapshot buffer when stopping instance tracers
It use to be that only the top level instance had a snapshot buffer (for
latency tracers like wakeup and irqsoff). When stopping a tracer in an
instance would not disable the snapshot buffer. This could have some
unintended consequences if the irqsoff tracer is enabled.
Consolidate the tracing_start/stop() with tracing_start/stop_tr() so that
all instances behave the same. The tracing_start/stop() functions will
just call their respective tracing_start/stop_tr() with the global_array
passed in.
Link: https://lkml.kernel.org/r/20231205220011.041220035@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes:
|
||
|
Steven Rostedt (Google)
|
d78ab79270 |
tracing: Stop current tracer when resizing buffer
When the ring buffer is being resized, it can cause side effects to the
running tracer. For instance, there's a race with irqsoff tracer that
swaps individual per cpu buffers between the main buffer and the snapshot
buffer. The resize operation modifies the main buffer and then the
snapshot buffer. If a swap happens in between those two operations it will
break the tracer.
Simply stop the running tracer before resizing the buffers and enable it
again when finished.
Link: https://lkml.kernel.org/r/20231205220010.748996423@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes:
|
||
|
Steven Rostedt (Google)
|
7be76461f3 |
tracing: Always update snapshot buffer size
It use to be that only the top level instance had a snapshot buffer (for
latency tracers like wakeup and irqsoff). The update of the ring buffer
size would check if the instance was the top level and if so, it would
also update the snapshot buffer as it needs to be the same as the main
buffer.
Now that lower level instances also has a snapshot buffer, they too need
to update their snapshot buffer sizes when the main buffer is changed,
otherwise the following can be triggered:
# cd /sys/kernel/tracing
# echo 1500 > buffer_size_kb
# mkdir instances/foo
# echo irqsoff > instances/foo/current_tracer
# echo 1000 > instances/foo/buffer_size_kb
Produces:
WARNING: CPU: 2 PID: 856 at kernel/trace/trace.c:1938 update_max_tr_single.part.0+0x27d/0x320
Which is:
ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
if (ret == -EBUSY) {
[..]
}
WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY); <== here
That's because ring_buffer_swap_cpu() has:
int ret = -EINVAL;
[..]
/* At least make sure the two buffers are somewhat the same */
if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages)
goto out;
[..]
out:
return ret;
}
Instead, update all instances' snapshot buffer sizes when their main
buffer size is updated.
Link: https://lkml.kernel.org/r/20231205220010.454662151@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes:
|
||
|
Yujie Liu
|
f032c53bea |
tracing/kprobes: Fix the order of argument descriptions
The order of descriptions should be consistent with the argument list of
the function, so "kretprobe" should be the second one.
int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
const char *name, const char *loc, ...)
Link: https://lore.kernel.org/all/20231031041305.3363712-1-yujie.liu@intel.com/
Fixes:
|
||
|
Masami Hiramatsu (Google)
|
ce51e6153f |
tracing: fprobe-event: Fix to check tracepoint event and return
Fix to check the tracepoint event is not valid with $retval. The commit |
||
|
Linus Torvalds
|
89cdf9d556 |
Merge tag 'net-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Including fixes from netfilter and bpf.
Current release - regressions:
- sched: fix SKB_NOT_DROPPED_YET splat under debug config
Current release - new code bugs:
- tcp:
- fix usec timestamps with TCP fastopen
- fix possible out-of-bounds reads in tcp_hash_fail()
- fix SYN option room calculation for TCP-AO
- tcp_sigpool: fix some off by one bugs
- bpf: fix compilation error without CGROUPS
- ptp:
- ptp_read() should not release queue
- fix tsevqs corruption
Previous releases - regressions:
- llc: verify mac len before reading mac header
Previous releases - always broken:
- bpf:
- fix check_stack_write_fixed_off() to correctly spill imm
- fix precision tracking for BPF_ALU | BPF_TO_BE | BPF_END
- check map->usercnt after timer->timer is assigned
- dsa: lan9303: consequently nested-lock physical MDIO
- dccp/tcp: call security_inet_conn_request() after setting IP addr
- tg3: fix the TX ring stall due to incorrect full ring handling
- phylink: initialize carrier state at creation
- ice: fix direction of VF rules in switchdev mode
Misc:
- fill in a bunch of missing MODULE_DESCRIPTION()s, more to come"
* tag 'net-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (84 commits)
net: ti: icss-iep: fix setting counter value
ptp: fix corrupted list in ptp_open
ptp: ptp_read should not release queue
net_sched: sch_fq: better validate TCA_FQ_WEIGHTS and TCA_FQ_PRIOMAP
net: kcm: fill in MODULE_DESCRIPTION()
net/sched: act_ct: Always fill offloading tuple iifidx
netfilter: nat: fix ipv6 nat redirect with mapped and scoped addresses
netfilter: xt_recent: fix (increase) ipv6 literal buffer length
ipvs: add missing module descriptions
netfilter: nf_tables: remove catchall element in GC sync path
netfilter: add missing module descriptions
drivers/net/ppp: use standard array-copy-function
net: enetc: shorten enetc_setup_xdp_prog() error message to fit NETLINK_MAX_FMTMSG_LEN
virtio/vsock: Fix uninit-value in virtio_transport_recv_pkt()
r8169: respect userspace disabling IFF_MULTICAST
selftests/bpf: get trusted cgrp from bpf_iter__cgroup directly
bpf: Let verifier consider {task,cgroup} is trusted in bpf_iter_reg
net: phylink: initialize carrier state at creation
test/vsock: add dobule bind connect test
test/vsock: refactor vsock_accept
...
|
||
|
Linus Torvalds
|
31e5f934ff |
Merge tag 'trace-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt: - Remove eventfs_file descriptor This is the biggest change, and the second part of making eventfs create its files dynamically. In 6.6 the first part was added, and that maintained a one to one mapping between eventfs meta descriptors and the directories and file inodes and dentries that were dynamically created. The directories were represented by a eventfs_inode and the files were represented by a eventfs_file. In v6.7 the eventfs_file is removed. As all events have the same directory make up (sched_switch has an "enable", "id", "format", etc files), the handing of what files are underneath each leaf eventfs directory is moved back to the tracing subsystem via a callback. When an event is added to the eventfs, it registers an array of evenfs_entry's. These hold the names of the files and the callbacks to call when the file is referenced. The callback gets the name so that the same callback may be used by multiple files. The callback then supplies the filesystem_operations structure needed to create this file. This has brought the memory footprint of creating multiple eventfs instances down by 2 megs each! - User events now has persistent events that are not associated to a single processes. These are privileged events that hang around even if no process is attached to them - Clean up of seq_buf There's talk about using seq_buf more to replace strscpy() and friends. But this also requires some minor modifications of seq_buf to be able to do this - Expand instance ring buffers individually Currently if boot up creates an instance, and a trace event is enabled on that instance, the ring buffer for that instance and the top level ring buffer are expanded (1.4 MB per CPU). This wastes memory as this happens when nothing is using the top level instance - Other minor clean ups and fixes * tag 'trace-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (34 commits) seq_buf: Export seq_buf_puts() seq_buf: Export seq_buf_putc() eventfs: Use simple_recursive_removal() to clean up dentries eventfs: Remove special processing of dput() of events directory eventfs: Delete eventfs_inode when the last dentry is freed eventfs: Hold eventfs_mutex when calling callback functions eventfs: Save ownership and mode eventfs: Test for ei->is_freed when accessing ei->dentry eventfs: Have a free_ei() that just frees the eventfs_inode eventfs: Remove "is_freed" union with rcu head eventfs: Fix kerneldoc of eventfs_remove_rec() tracing: Have the user copy of synthetic event address use correct context eventfs: Remove extra dget() in eventfs_create_events_dir() tracing: Have trace_event_file have ref counters seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str() eventfs: Fix typo in eventfs_inode union comment eventfs: Fix WARN_ON() in create_file_dentry() powerpc: Remove initialisation of readpos tracing/histograms: Simplify last_cmd_set() seq_buf: fix a misleading comment ... |
||
|
Dave Marchevsky
|
391145ba2a |
bpf: Add __bpf_kfunc_{start,end}_defs macros
BPF kfuncs are meant to be called from BPF programs. Accordingly, most
kfuncs are not called from anywhere in the kernel, which the
-Wmissing-prototypes warning is unhappy about. We've peppered
__diag_ignore_all("-Wmissing-prototypes", ... everywhere kfuncs are
defined in the codebase to suppress this warning.
This patch adds two macros meant to bound one or many kfunc definitions.
All existing kfunc definitions which use these __diag calls to suppress
-Wmissing-prototypes are migrated to use the newly-introduced macros.
A new __diag_ignore_all - for "-Wmissing-declarations" - is added to the
__bpf_kfunc_start_defs macro based on feedback from Andrii on an earlier
version of this patch [0] and another recent mailing list thread [1].
In the future we might need to ignore different warnings or do other
kfunc-specific things. This change will make it easier to make such
modifications for all kfunc defs.
[0]: https://lore.kernel.org/bpf/CAEf4BzaE5dRWtK6RPLnjTW-MW9sx9K3Fn6uwqCTChK2Dcb1Xig@mail.gmail.com/
[1]: https://lore.kernel.org/bpf/ZT+2qCc%2FaXep0%2FLf@krava/
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20231031215625.2343848-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
||
|
Steven Rostedt (Google)
|
4f7969bcd6 |
tracing: Have the user copy of synthetic event address use correct context
A synthetic event is created by the synthetic event interface that can
read both user or kernel address memory. In reality, it reads any
arbitrary memory location from within the kernel. If the address space is
in USER (where CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE is set) then
it uses strncpy_from_user_nofault() to copy strings otherwise it uses
strncpy_from_kernel_nofault().
But since both functions use the same variable there's no annotation to
what that variable is (ie. __user). This makes sparse complain.
Quiet sparse by typecasting the strncpy_from_user_nofault() variable to
a __user pointer.
Link: https://lore.kernel.org/linux-trace-kernel/20231031151033.73c42e23@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes:
|
||
|
Steven Rostedt (Google)
|
bb32500fb9 |
tracing: Have trace_event_file have ref counters
The following can crash the kernel:
# cd /sys/kernel/tracing
# echo 'p:sched schedule' > kprobe_events
# exec 5>>events/kprobes/sched/enable
# > kprobe_events
# exec 5>&-
The above commands:
1. Change directory to the tracefs directory
2. Create a kprobe event (doesn't matter what one)
3. Open bash file descriptor 5 on the enable file of the kprobe event
4. Delete the kprobe event (removes the files too)
5. Close the bash file descriptor 5
The above causes a crash!
BUG: kernel NULL pointer dereference, address: 0000000000000028
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 6 PID: 877 Comm: bash Not tainted 6.5.0-rc4-test-00008-g2c6b6b1029d4-dirty #186
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:tracing_release_file_tr+0xc/0x50
What happens here is that the kprobe event creates a trace_event_file
"file" descriptor that represents the file in tracefs to the event. It
maintains state of the event (is it enabled for the given instance?).
Opening the "enable" file gets a reference to the event "file" descriptor
via the open file descriptor. When the kprobe event is deleted, the file is
also deleted from the tracefs system which also frees the event "file"
descriptor.
But as the tracefs file is still opened by user space, it will not be
totally removed until the final dput() is called on it. But this is not
true with the event "file" descriptor that is already freed. If the user
does a write to or simply closes the file descriptor it will reference the
event "file" descriptor that was just freed, causing a use-after-free bug.
To solve this, add a ref count to the event "file" descriptor as well as a
new flag called "FREED". The "file" will not be freed until the last
reference is released. But the FREE flag will be set when the event is
removed to prevent any more modifications to that event from happening,
even if there's still a reference to the event "file" descriptor.
Link: https://lore.kernel.org/linux-trace-kernel/20231031000031.1e705592@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20231031122453.7a48b923@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes:
|
||
|
Linus Torvalds
|
05bf73aa27 |
Merge tag 'probes-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes updates from Masami Hiramatsu:
"Cleanups:
- kprobes: Fixes typo in kprobes samples
- tracing/eprobes: Remove 'break' after return
kretprobe/fprobe performance improvements:
- lib: Introduce new `objpool`, which is a high performance lockless
object queue. This uses per-cpu ring array to allocate/release
objects from the pre-allocated object pool.
Since the index of ring array is a 32bit sequential counter, we can
retry to push/pop the object pointer from the ring without lock (as
seq-lock does)
- lib: Add an objpool test module to test the functionality and
evaluate the performance under some circumstances
- kprobes/fprobe: Improve kretprobe and rethook scalability
performance with objpool.
This improves both legacy kretprobe and fprobe exit handler (which
is based on rethook) to be scalable on SMP systems. Even with
8-threads parallel test, it shows a great scalability improvement
- Remove unneeded freelist.h which is replaced by objpool
- objpool: Add maintainers entry for the objpool
- objpool: Fix to remove unused include header lines"
* tag 'probes-v6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
kprobes: unused header files removed
MAINTAINERS: objpool added
kprobes: freelist.h removed
kprobes: kretprobe scalability improvement
lib: objpool test module added
lib: objpool added: ring-array based lockless MPMC
tracing/eprobe: drop unneeded breaks
samples: kprobes: Fixes a typo
|
||
|
Linus Torvalds
|
89ed67ef12 |
Merge tag 'net-next-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Jakub Kicinski:
"Core & protocols:
- Support usec resolution of TCP timestamps, enabled selectively by a
route attribute.
- Defer regular TCP ACK while processing socket backlog, try to send
a cumulative ACK at the end. Increase single TCP flow performance
on a 200Gbit NIC by 20% (100Gbit -> 120Gbit).
- The Fair Queuing (FQ) packet scheduler:
- add built-in 3 band prio / WRR scheduling
- support bypass if the qdisc is mostly idle (5% speed up for TCP RR)
- improve inactive flow reporting
- optimize the layout of structures for better cache locality
- Support TCP Authentication Option (RFC 5925, TCP-AO), a more modern
replacement for the old MD5 option.
- Add more retransmission timeout (RTO) related statistics to
TCP_INFO.
- Support sending fragmented skbs over vsock sockets.
- Make sure we send SIGPIPE for vsock sockets if socket was
shutdown().
- Add sysctl for ignoring lower limit on lifetime in Router
Advertisement PIO, based on an in-progress IETF draft.
- Add sysctl to control activation of TCP ping-pong mode.
- Add sysctl to make connection timeout in MPTCP configurable.
- Support rcvlowat and notsent_lowat on MPTCP sockets, to help apps
limit the number of wakeups.
- Support netlink GET for MDB (multicast forwarding), allowing user
space to request a single MDB entry instead of dumping the entire
table.
- Support selective FDB flushing in the VXLAN tunnel driver.
- Allow limiting learned FDB entries in bridges, prevent OOM attacks.
- Allow controlling via configfs netconsole targets which were
created via the kernel cmdline at boot, rather than via configfs at
runtime.
- Support multiple PTP timestamp event queue readers with different
filters.
- MCTP over I3C.
BPF:
- Add new veth-like netdevice where BPF program defines the logic of
the xmit routine. It can operate in L3 and L2 mode.
- Support exceptions - allow asserting conditions which should never
be true but are hard for the verifier to infer. With some extra
flexibility around handling of the exit / failure:
https://lwn.net/Articles/938435/
- Add support for local per-cpu kptr, allow allocating and storing
per-cpu objects in maps. Access to those objects operates on the
value for the current CPU.
This allows to deprecate local one-off implementations of per-CPU
storage like BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE maps.
- Extend cgroup BPF sockaddr hooks for UNIX sockets. The use case is
for systemd to re-implement the LogNamespace feature which allows
running multiple instances of systemd-journald to process the logs
of different services.
- Enable open-coded task_vma iteration, after maple tree conversion
made it hard to directly walk VMAs in tracing programs.
- Add open-coded task, css_task and css iterator support. One of the
use cases is customizable OOM victim selection via BPF.
- Allow source address selection with bpf_*_fib_lookup().
- Add ability to pin BPF timer to the current CPU.
- Prevent creation of infinite loops by combining tail calls and
fentry/fexit programs.
- Add missed stats for kprobes to retrieve the number of missed
kprobe executions and subsequent executions of BPF programs.
- Inherit system settings for CPU security mitigations.
- Add BPF v4 CPU instruction support for arm32 and s390x.
Changes to common code:
- overflow: add DEFINE_FLEX() for on-stack definition of structs with
flexible array members.
- Process doc update with more guidance for reviewers.
Driver API:
- Simplify locking in WiFi (cfg80211 and mac80211 layers), use wiphy
mutex in most places and remove a lot of smaller locks.
- Create a common DPLL configuration API. Allow configuring and
querying state of PLL circuits used for clock syntonization, in
network time distribution.
- Unify fragmented and full page allocation APIs in page pool code.
Let drivers be ignorant of PAGE_SIZE.
- Rework PHY state machine to avoid races with calls to phy_stop().
- Notify DSA drivers of MAC address changes on user ports, improve
correctness of offloads which depend on matching port MAC
addresses.
- Allow antenna control on injected WiFi frames.
- Reduce the number of variants of napi_schedule().
- Simplify error handling when composing devlink health messages.
Misc:
- A lot of KCSAN data race "fixes", from Eric.
- A lot of __counted_by() annotations, from Kees.
- A lot of strncpy -> strscpy and printf format fixes.
- Replace master/slave terminology with conduit/user in DSA drivers.
- Handful of KUnit tests for netdev and WiFi core.
Removed:
- AppleTalk COPS.
- AppleTalk ipddp.
- TI AR7 CPMAC Ethernet driver.
Drivers:
- Ethernet high-speed NICs:
- Intel (100G, ice, idpf):
- add a driver for the Intel E2000 IPUs
- make CRC/FCS stripping configurable
- cross-timestamping for E823 devices
- basic support for E830 devices
- use aux-bus for managing client drivers
- i40e: report firmware versions via devlink
- nVidia/Mellanox:
- support 4-port NICs
- increase max number of channels to 256
- optimize / parallelize SF creation flow
- Broadcom (bnxt):
- enhance NIC temperature reporting
- support PAM4 speeds and lane configuration
- Marvell OcteonTX2:
- PTP pulse-per-second output support
- enable hardware timestamping for VFs
- Solarflare/AMD:
- conntrack NAT offload and offload for tunnels
- Wangxun (ngbe/txgbe):
- expose HW statistics
- Pensando/AMD:
- support PCI level reset
- narrow down the condition under which skbs are linearized
- Netronome/Corigine (nfp):
- support CHACHA20-POLY1305 crypto in IPsec offload
- Ethernet NICs embedded, slower, virtual:
- Synopsys (stmmac):
- add Loongson-1 SoC support
- enable use of HW queues with no offload capabilities
- enable PPS input support on all 5 channels
- increase TX coalesce timer to 5ms
- RealTek USB (r8152): improve efficiency of Rx by using GRO frags
- xen: support SW packet timestamping
- add drivers for implementations based on TI's PRUSS (AM64x EVM)
- nVidia/Mellanox Ethernet datacenter switches:
- avoid poor HW resource use on Spectrum-4 by better block
selection for IPv6 multicast forwarding and ordering of blocks
in ACL region
- Ethernet embedded switches:
- Microchip:
- support configuring the drive strength for EMI compliance
- ksz9477: partial ACL support
- ksz9477: HSR offload
- ksz9477: Wake on LAN
- Realtek:
- rtl8366rb: respect device tree config of the CPU port
- Ethernet PHYs:
- support Broadcom BCM5221 PHYs
- TI dp83867: support hardware LED blinking
- CAN:
- add support for Linux-PHY based CAN transceivers
- at91_can: clean up and use rx-offload helpers
- WiFi:
- MediaTek (mt76):
- new sub-driver for mt7925 USB/PCIe devices
- HW wireless <> Ethernet bridging in MT7988 chips
- mt7603/mt7628 stability improvements
- Qualcomm (ath12k):
- WCN7850:
- enable 320 MHz channels in 6 GHz band
- hardware rfkill support
- enable IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS to
make scan faster
- read board data variant name from SMBIOS
- QCN9274: mesh support
- RealTek (rtw89):
- TDMA-based multi-channel concurrency (MCC)
- Silicon Labs (wfx):
- Remain-On-Channel (ROC) support
- Bluetooth:
- ISO: many improvements for broadcast support
- mark BCM4378/BCM4387 as BROKEN_LE_CODED
- add support for QCA2066
- btmtksdio: enable Bluetooth wakeup from suspend"
* tag 'net-next-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1816 commits)
net: pcs: xpcs: Add 2500BASE-X case in get state for XPCS drivers
net: bpf: Use sockopt_lock_sock() in ip_sock_set_tos()
net: mana: Use xdp_set_features_flag instead of direct assignment
vxlan: Cleanup IFLA_VXLAN_PORT_RANGE entry in vxlan_get_size()
iavf: delete the iavf client interface
iavf: add a common function for undoing the interrupt scheme
iavf: use unregister_netdev
iavf: rely on netdev's own registered state
iavf: fix the waiting time for initial reset
iavf: in iavf_down, don't queue watchdog_task if comms failed
iavf: simplify mutex_trylock+sleep loops
iavf: fix comments about old bit locks
doc/netlink: Update schema to support cmd-cnt-name and cmd-max-name
tools: ynl: introduce option to process unknown attributes or types
ipvlan: properly track tx_errors
netdevsim: Block until all devices are released
nfp: using napi_build_skb() to replace build_skb()
net: dsa: microchip: ksz9477: Fix spelling mistake "Enery" -> "Energy"
net: dsa: microchip: Ensure Stable PME Pin State for Wake-on-LAN
net: dsa: microchip: Refactor switch shutdown routine for WoL preparation
...
|
||
|
Linus Torvalds
|
3b3f874cc1 |
Merge tag 'vfs-6.7.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
"This contains the usual miscellaneous features, cleanups, and fixes
for vfs and individual fses.
Features:
- Rename and export helpers that get write access to a mount. They
are used in overlayfs to get write access to the upper mount.
- Print the pretty name of the root device on boot failure. This
helps in scenarios where we would usually only print
"unknown-block(1,2)".
- Add an internal SB_I_NOUMASK flag. This is another part in the
endless POSIX ACL saga in a way.
When POSIX ACLs are enabled via SB_POSIXACL the vfs cannot strip
the umask because if the relevant inode has POSIX ACLs set it might
take the umask from there. But if the inode doesn't have any POSIX
ACLs set then we apply the umask in the filesytem itself. So we end
up with:
(1) no SB_POSIXACL -> strip umask in vfs
(2) SB_POSIXACL -> strip umask in filesystem
The umask semantics associated with SB_POSIXACL allowed filesystems
that don't even support POSIX ACLs at all to raise SB_POSIXACL
purely to avoid umask stripping. That specifically means NFS v4 and
Overlayfs. NFS v4 does it because it delegates this to the server
and Overlayfs because it needs to delegate umask stripping to the
upper filesystem, i.e., the filesystem used as the writable layer.
This went so far that SB_POSIXACL is raised eve on kernels that
don't even have POSIX ACL support at all.
Stop this blatant abuse and add SB_I_NOUMASK which is an internal
superblock flag that filesystems can raise to opt out of umask
handling. That should really only be the two mentioned above. It's
not that we want any filesystems to do this. Ideally we have all
umask handling always in the vfs.
- Make overlayfs use SB_I_NOUMASK too.
- Now that we have SB_I_NOUMASK, stop checking for SB_POSIXACL in
IS_POSIXACL() if the kernel doesn't have support for it. This is a
very old patch but it's only possible to do this now with the wider
cleanup that was done.
- Follow-up work on fake path handling from last cycle. Citing mostly
from Amir:
When overlayfs was first merged, overlayfs files of regular files
and directories, the ones that are installed in file table, had a
"fake" path, namely, f_path is the overlayfs path and f_inode is
the "real" inode on the underlying filesystem.
In v6.5, we took another small step by introducing of the
backing_file container and the file_real_path() helper. This change
allowed vfs and filesystem code to get the "real" path of an
overlayfs backing file. With this change, we were able to make
fsnotify work correctly and report events on the "real" filesystem
objects that were accessed via overlayfs.
This method works fine, but it still leaves the vfs vulnerable to
new code that is not aware of files with fake path. A recent
example is commit
|
||
|
Kees Cook
|
dcc4e5728e |
seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_str()
Solve two ergonomic issues with struct seq_buf; 1) Too much boilerplate is required to initialize: struct seq_buf s; char buf[32]; seq_buf_init(s, buf, sizeof(buf)); Instead, we can build this directly on the stack. Provide DECLARE_SEQ_BUF() macro to do this: DECLARE_SEQ_BUF(s, 32); 2) %NUL termination is fragile and requires 2 steps to get a valid C String (and is a layering violation exposing the "internals" of seq_buf): seq_buf_terminate(s); do_something(s->buffer); Instead, we can just return s->buffer directly after terminating it in the refactored seq_buf_terminate(), now known as seq_buf_str(): do_something(seq_buf_str(s)); Link: https://lore.kernel.org/linux-trace-kernel/20231027155634.make.260-kees@kernel.org Link: https://lore.kernel.org/linux-trace-kernel/20231026194033.it.702-kees@kernel.org/ Cc: Yosry Ahmed <yosryahmed@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Justin Stitt <justinstitt@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Petr Mladek <pmladek@suse.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Yun Zhou <yun.zhou@windriver.com> Cc: Jacob Keller <jacob.e.keller@intel.com> Cc: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> |
||
|
Andrii Nakryiko
|
926fe783c8 |
tracing/kprobes: Fix symbol counting logic by looking at modules as well
Recent changes to count number of matching symbols when creating
a kprobe event failed to take into account kernel modules. As such, it
breaks kprobes on kernel module symbols, by assuming there is no match.
Fix this my calling module_kallsyms_on_each_symbol() in addition to
kallsyms_on_each_match_symbol() to perform a proper counting.
Link: https://lore.kernel.org/all/20231027233126.2073148-1-andrii@kernel.org/
Cc: Francis Laniel <flaniel@linux.microsoft.com>
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Fixes:
|
||
|
Yujie Liu
|
e0f831836c |
tracing/kprobes: Fix the description of variable length arguments
Fix the following kernel-doc warnings:
kernel/trace/trace_kprobe.c:1029: warning: Excess function parameter 'args' description in '__kprobe_event_gen_cmd_start'
kernel/trace/trace_kprobe.c:1097: warning: Excess function parameter 'args' description in '__kprobe_event_add_fields'
Refer to the usage of variable length arguments elsewhere in the kernel
code, "@..." is the proper way to express it in the description.
Link: https://lore.kernel.org/all/20231027041315.2613166-1-yujie.liu@intel.com/
Fixes:
|
||
|
Jakub Kicinski
|
ec4c20ca09 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR. Conflicts: net/mac80211/rx.c |
||
|
wuqiang.matt
|
4758560fa2 |
kprobes: unused header files removed
As kernel test robot reported, lib/test_objpool.c (trace:probes/for-next) has linux/version.h included, but version.h is not used at all. Then more unused headers are found in test_objpool.c and rethook.c, and all of them should be removed. Link: https://lore.kernel.org/all/20231023112245.6112-1-wuqiang.matt@bytedance.com/ Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202310191512.vvypKU5Z-lkp@intel.com/ Signed-off-by: wuqiang.matt <wuqiang.matt@bytedance.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> |
||
|
Christophe JAILLET
|
545db7e21e |
tracing/histograms: Simplify last_cmd_set()
Turn a kzalloc()+strcpy()+strncat() into an equivalent and less verbose kasprintf(). Link: https://lore.kernel.org/linux-trace-kernel/30b6fb04dadc10a03cc1ad08f5d8a93ef623a167.1697899346.git.christophe.jaillet@wanadoo.fr Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Mukesh ojha <quic_mojha@quicinc.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> |
||
|
Matthew Wilcox (Oracle)
|
d0ed46b603 |
tracing: Move readpos from seq_buf to trace_seq
To make seq_buf more lightweight as a string buf, move the readpos member from seq_buf to its container, trace_seq. That puts the responsibility of maintaining the readpos entirely in the tracing code. If some future users want to package up the readpos with a seq_buf, we can define a new struct then. Link: https://lore.kernel.org/linux-trace-kernel/20231020033545.2587554-2-willy@infradead.org Cc: Kees Cook <keescook@chromium.org> Cc: Justin Stitt <justinstitt@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Petr Mladek <pmladek@suse.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> |
||
|
Dan Carpenter
|
5264a2f4bb |
tracing: Fix a NULL vs IS_ERR() bug in event_subsystem_dir()
The eventfs_create_dir() function returns error pointers, it never returns
NULL. Update the check to reflect that.
Link: https://lore.kernel.org/linux-trace-kernel/ff641474-84e2-46a7-9d7a-62b251a1050c@moroto.mountain
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes:
|
||
|
Francis Laniel
|
b022f0c7e4 |
tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols
When a kprobe is attached to a function that's name is not unique (is
static and shares the name with other functions in the kernel), the
kprobe is attached to the first function it finds. This is a bug as the
function that it is attaching to is not necessarily the one that the
user wants to attach to.
Instead of blindly picking a function to attach to what is ambiguous,
error with EADDRNOTAVAIL to let the user know that this function is not
unique, and that the user must use another unique function with an
address offset to get to the function they want to attach to.
Link: https://lore.kernel.org/all/20231020104250.9537-2-flaniel@linux.microsoft.com/
Cc: stable@vger.kernel.org
Fixes:
|
||
|
Jakub Kicinski
|
041c3466f3 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR. net/mac80211/key.c |
||
|
Amir Goldstein
|
08582d678f |
fs: create helper file_user_path() for user displayed mapped file path
Overlayfs uses backing files with "fake" overlayfs f_path and "real" underlying f_inode, in order to use underlying inode aops for mapped files and to display the overlayfs path in /proc/<pid>/maps. In preparation for storing the overlayfs "fake" path instead of the underlying "real" path in struct backing_file, define a noop helper file_user_path() that returns f_path for now. Use the new helper in procfs and kernel logs whenever a path of a mapped file is displayed to users. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231009153712.1566422-3-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org> |
||
|
wuqiang.matt
|
4bbd934556 |
kprobes: kretprobe scalability improvement
kretprobe is using freelist to manage return-instances, but freelist,
as LIFO queue based on singly linked list, scales badly and reduces
the overall throughput of kretprobed routines, especially for high
contention scenarios.
Here's a typical throughput test of sys_prctl (counts in 10 seconds,
measured with perf stat -a -I 10000 -e syscalls:sys_enter_prctl):
OS: Debian 10 X86_64, Linux 6.5rc7 with freelist
HW: XEON 8336C x 2, 64 cores/128 threads, DDR4 3200MT/s
1T 2T 4T 8T 16T 24T
24150045 29317964 15446741 12494489 18287272 17708768
32T 48T 64T 72T 96T 128T
16200682 13737658 11645677 11269858 10470118 9931051
This patch introduces objpool to replace freelist. objpool is a
high performance queue, which can bring near-linear scalability
to kretprobed routines. Tests of kretprobe throughput show the
biggest ratio as 159x of original freelist. Here's the result:
1T 2T 4T 8T 16T
native: 41186213 82336866 164250978 328662645 658810299
freelist: 24150045 29317964 15446741 12494489 18287272
objpool: 23926730 48010314 96125218 191782984 385091769
32T 48T 64T 96T 128T
native: 1330338351 1969957941 2512291791 2615754135 2671040914
freelist: 16200682 13737658 11645677 10470118 9931051
objpool: 764481096 1147149781 1456220214 1502109662 1579015050
Testings on 96-core ARM64 output similarly, but with the biggest
ratio up to 448x:
OS: Debian 10 AARCH64, Linux 6.5rc7
HW: Kunpeng-920 96 cores/2 sockets/4 NUMA nodes, DDR4 2933 MT/s
1T 2T 4T 8T 16T
native: . 30066096 63569843 126194076 257447289 505800181
freelist: 16152090 11064397 11124068 7215768 5663013
objpool: 13997541 28032100 55726624 110099926 221498787
24T 32T 48T 64T 96T
native: 763305277 1015925192 1521075123 2033009392 3021013752
freelist: 5015810 4602893 3766792 3382478 2945292
objpool: 328192025 439439564 668534502 887401381 1319972072
Link: https://lore.kernel.org/all/20231017135654.82270-4-wuqiang.matt@bytedance.com/
Signed-off-by: wuqiang.matt <wuqiang.matt@bytedance.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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Jakub Kicinski
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a3c2dd9648 |
Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2023-10-16
We've added 90 non-merge commits during the last 25 day(s) which contain
a total of 120 files changed, 3519 insertions(+), 895 deletions(-).
The main changes are:
1) Add missed stats for kprobes to retrieve the number of missed kprobe
executions and subsequent executions of BPF programs, from Jiri Olsa.
2) Add cgroup BPF sockaddr hooks for unix sockets. The use case is
for systemd to reimplement the LogNamespace feature which allows
running multiple instances of systemd-journald to process the logs
of different services, from Daan De Meyer.
3) Implement BPF CPUv4 support for s390x BPF JIT, from Ilya Leoshkevich.
4) Improve BPF verifier log output for scalar registers to better
disambiguate their internal state wrt defaults vs min/max values
matching, from Andrii Nakryiko.
5) Extend the BPF fib lookup helpers for IPv4/IPv6 to support retrieving
the source IP address with a new BPF_FIB_LOOKUP_SRC flag,
from Martynas Pumputis.
6) Add support for open-coded task_vma iterator to help with symbolization
for BPF-collected user stacks, from Dave Marchevsky.
7) Add libbpf getters for accessing individual BPF ring buffers which
is useful for polling them individually, for example, from Martin Kelly.
8) Extend AF_XDP selftests to validate the SHARED_UMEM feature,
from Tushar Vyavahare.
9) Improve BPF selftests cross-building support for riscv arch,
from Björn Töpel.
10) Add the ability to pin a BPF timer to the same calling CPU,
from David Vernet.
11) Fix libbpf's bpf_tracing.h macros for riscv to use the generic
implementation of PT_REGS_SYSCALL_REGS() to access syscall arguments,
from Alexandre Ghiti.
12) Extend libbpf to support symbol versioning for uprobes, from Hengqi Chen.
13) Fix bpftool's skeleton code generation to guarantee that ELF data
is 8 byte aligned, from Ian Rogers.
14) Inherit system-wide cpu_mitigations_off() setting for Spectre v1/v4
security mitigations in BPF verifier, from Yafang Shao.
15) Annotate struct bpf_stack_map with __counted_by attribute to prepare
BPF side for upcoming __counted_by compiler support, from Kees Cook.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (90 commits)
bpf: Ensure proper register state printing for cond jumps
bpf: Disambiguate SCALAR register state output in verifier logs
selftests/bpf: Make align selftests more robust
selftests/bpf: Improve missed_kprobe_recursion test robustness
selftests/bpf: Improve percpu_alloc test robustness
selftests/bpf: Add tests for open-coded task_vma iter
bpf: Introduce task_vma open-coded iterator kfuncs
selftests/bpf: Rename bpf_iter_task_vma.c to bpf_iter_task_vmas.c
bpf: Don't explicitly emit BTF for struct btf_iter_num
bpf: Change syscall_nr type to int in struct syscall_tp_t
net/bpf: Avoid unused "sin_addr_len" warning when CONFIG_CGROUP_BPF is not set
bpf: Avoid unnecessary audit log for CPU security mitigations
selftests/bpf: Add tests for cgroup unix socket address hooks
selftests/bpf: Make sure mount directory exists
documentation/bpf: Document cgroup unix socket address hooks
bpftool: Add support for cgroup unix socket address hooks
libbpf: Add support for cgroup unix socket address hooks
bpf: Implement cgroup sockaddr hooks for unix sockets
bpf: Add bpf_sock_addr_set_sun_path() to allow writing unix sockaddr from bpf
bpf: Propagate modified uaddrlen from cgroup sockaddr programs
...
====================
Link: https://lore.kernel.org/r/20231016204803.30153-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Masami Hiramatsu (Google)
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700b2b4397 |
fprobe: Fix to ensure the number of active retprobes is not zero
The number of active retprobes can be zero but it is not acceptable,
so return EINVAL error if detected.
Link: https://lore.kernel.org/all/169750018550.186853.11198884812017796410.stgit@devnote2/
Reported-by: wuqiang.matt <wuqiang.matt@bytedance.com>
Closes: https://lore.kernel.org/all/20231016222103.cb9f426edc60220eabd8aa6a@kernel.org/
Fixes:
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Artem Savkov
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ba8ea72388 |
bpf: Change syscall_nr type to int in struct syscall_tp_t
linux-rt-devel tree contains a patch (b1773eac3f29c ("sched: Add support
for lazy preemption")) that adds an extra member to struct trace_entry.
This causes the offset of args field in struct trace_event_raw_sys_enter
be different from the one in struct syscall_trace_enter:
struct trace_event_raw_sys_enter {
struct trace_entry ent; /* 0 12 */
/* XXX last struct has 3 bytes of padding */
/* XXX 4 bytes hole, try to pack */
long int id; /* 16 8 */
long unsigned int args[6]; /* 24 48 */
/* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */
char __data[]; /* 72 0 */
/* size: 72, cachelines: 2, members: 4 */
/* sum members: 68, holes: 1, sum holes: 4 */
/* paddings: 1, sum paddings: 3 */
/* last cacheline: 8 bytes */
};
struct syscall_trace_enter {
struct trace_entry ent; /* 0 12 */
/* XXX last struct has 3 bytes of padding */
int nr; /* 12 4 */
long unsigned int args[]; /* 16 0 */
/* size: 16, cachelines: 1, members: 3 */
/* paddings: 1, sum paddings: 3 */
/* last cacheline: 16 bytes */
};
This, in turn, causes perf_event_set_bpf_prog() fail while running bpf
test_profiler testcase because max_ctx_offset is calculated based on the
former struct, while off on the latter:
10488 if (is_tracepoint || is_syscall_tp) {
10489 int off = trace_event_get_offsets(event->tp_event);
10490
10491 if (prog->aux->max_ctx_offset > off)
10492 return -EACCES;
10493 }
What bpf program is actually getting is a pointer to struct
syscall_tp_t, defined in kernel/trace/trace_syscalls.c. This patch fixes
the problem by aligning struct syscall_tp_t with struct
syscall_trace_(enter|exit) and changing the tests to use these structs
to dereference context.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20231013054219.172920-1-asavkov@redhat.com
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Julia Lawall
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f843249cb6 |
tracing/eprobe: drop unneeded breaks
Drop break after return. Link: https://lore.kernel.org/all/20230928104334.41215-1-Julia.Lawall@inria.fr/ Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> |