ftrace has two flavors:
1) static: Where every function always calls the ftrace trampoline
2) dynamic: Where each function has nops that can be changed on demand to
jump to the ftrace trampoline when needed.
The static flavor has very high performance overhead and was only created
to make it easier for architectures to implement the dynamic flavor. An
architecture developer can first implement the static ftrace to make sure
the trampolines work before working on the more complicated dynamic aspect
of ftrace. Once the architecture can support dynamic ftrace, there's no
reason to continue to support the static flavor. In fact, the static
flavor tends to bitrot and bugs start to appear in them.
Remove the prompt to pick DYNAMIC_FTRACE and simply enable it if the
architecture supports it.
Link: https://lore.kernel.org/all/f7e12c6d-892e-4ca3-9ef0-fbb524d04a48@ghiti.fr/
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: ChenMiao <chenmiao.ku@gmail.com>
Link: https://lore.kernel.org/20250703115222.2d7c8cd5@batman.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When the ring buffer was first introduced, reading the non-consuming
"trace" file required disabling the writing of the ring buffer. To make
sure the writing was fully disabled before iterating the buffer with a
non-consuming read, it would set the disable flag of the buffer and then
call an RCU synchronization to make sure all the buffers were
synchronized.
The function ring_buffer_read_start() originally would initialize the
iterator and call an RCU synchronization, but this was for each individual
per CPU buffer where this would get called many times on a machine with
many CPUs before the trace file could be read. The commit 72c9ddfd4c
("ring-buffer: Make non-consuming read less expensive with lots of cpus.")
separated ring_buffer_read_start into ring_buffer_read_prepare(),
ring_buffer_read_sync() and then ring_buffer_read_start() to allow each of
the per CPU buffers to be prepared, call the read_buffer_read_sync() once,
and then the ring_buffer_read_start() for each of the CPUs which made
things much faster.
The commit 1039221cc2 ("ring-buffer: Do not disable recording when there
is an iterator") removed the requirement of disabling the recording of the
ring buffer in order to iterate it, but it did not remove the
synchronization that was happening that was required to wait for all the
buffers to have no more writers. It's now OK for the buffers to have
writers and no synchronization is needed.
Remove the synchronization and put back the interface for the ring buffer
iterator back before commit 72c9ddfd4c was applied.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250630180440.3eabb514@batman.local.home
Reported-by: David Howells <dhowells@redhat.com>
Fixes: 1039221cc2 ("ring-buffer: Do not disable recording when there is an iterator")
Tested-by: David Howells <dhowells@redhat.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Pull tracing fixes from Steven Rostedt:
- Fix timerlat with use of FORTIFY_SOURCE
FORTIFY_SOURCE was added to the stack tracer where it compares the
entry->caller array to having entry->size elements.
timerlat has the following:
memcpy(&entry->caller, fstack->calls, size);
entry->size = size;
Which triggers FORTIFY_SOURCE as the caller is populated before the
entry->size is initialized.
Swap the order to satisfy FORTIFY_SOURCE logic.
- Add down_write(trace_event_sem) when adding trace events in modules
Trace events being added to the ftrace_events array are protected by
the trace_event_sem semaphore. But when loading modules that have
trace events, the addition of the events are not protected by the
semaphore and loading two modules that have events at the same time
can corrupt the list.
Also add a lockdep_assert_held(trace_event_sem) to
_trace_add_event_dirs() to confirm it is held when iterating the
list.
* tag 'trace-v6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Add down_write(trace_event_sem) when adding trace event
tracing/osnoise: Fix crash in timerlat_dump_stack()
When a module is loaded, it adds trace events defined by the module. It
may also need to modify the modules trace printk formats to replace enum
names with their values.
If two modules are loaded at the same time, the adding of the event to the
ftrace_events list can corrupt the walking of the list in the code that is
modifying the printk format strings and crash the kernel.
The addition of the event should take the trace_event_sem for write while
it adds the new event.
Also add a lockdep_assert_held() on that semaphore in
__trace_add_event_dirs() as it iterates the list.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/20250718223158.799bfc0c@batman.local.home
Reported-by: Fusheng Huang(黄富生) <Fusheng.Huang@luxshare-ict.com>
Closes: https://lore.kernel.org/all/20250717105007.46ccd18f@batman.local.home/
Fixes: 110bf2b764 ("tracing: add protection around module events unload")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
We have observed kernel panics when using timerlat with stack saving,
with the following dmesg output:
memcpy: detected buffer overflow: 88 byte write of buffer size 0
WARNING: CPU: 2 PID: 8153 at lib/string_helpers.c:1032 __fortify_report+0x55/0xa0
CPU: 2 UID: 0 PID: 8153 Comm: timerlatu/2 Kdump: loaded Not tainted 6.15.3-200.fc42.x86_64 #1 PREEMPT(lazy)
Call Trace:
<TASK>
? trace_buffer_lock_reserve+0x2a/0x60
__fortify_panic+0xd/0xf
__timerlat_dump_stack.cold+0xd/0xd
timerlat_dump_stack.part.0+0x47/0x80
timerlat_fd_read+0x36d/0x390
vfs_read+0xe2/0x390
? syscall_exit_to_user_mode+0x1d5/0x210
ksys_read+0x73/0xe0
do_syscall_64+0x7b/0x160
? exc_page_fault+0x7e/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
__timerlat_dump_stack() constructs the ftrace stack entry like this:
struct stack_entry *entry;
...
memcpy(&entry->caller, fstack->calls, size);
entry->size = fstack->nr_entries;
Since commit e7186af7fb ("tracing: Add back FORTIFY_SOURCE logic to
kernel_stack event structure"), struct stack_entry marks its caller
field with __counted_by(size). At the time of the memcpy, entry->size
contains garbage from the ringbuffer, which under some circumstances is
zero, triggering a kernel panic by buffer overflow.
Populate the size field before the memcpy so that the out-of-bounds
check knows the correct size. This is analogous to
__ftrace_trace_stack().
Cc: stable@vger.kernel.org
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Attila Fazekas <afazekas@redhat.com>
Link: https://lore.kernel.org/20250716143601.7313-1-tglozar@redhat.com
Fixes: e7186af7fb ("tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure")
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Patch series "relayfs: misc changes", v5.
The series mostly focuses on the error counters which helps every user
debug their own kernel module.
This patch (of 5):
prev_padding represents the unused space of certain subbuffer. If the
content of a call of relay_write() exceeds the limit of the remainder of
this subbuffer, it will skip storing in the rest space and record the
start point as buf->prev_padding in relay_switch_subbuf(). Since the buf
is a per-cpu big buffer, the point of prev_padding as a global value for
the whole buffer instead of a single subbuffer (whose padding info is
stored in buf->padding[]) seems meaningless from the real use cases, so we
don't bother to record it any more.
Link: https://lkml.kernel.org/r/20250612061201.34272-1-kerneljasonxing@gmail.com
Link: https://lkml.kernel.org/r/20250612061201.34272-2-kerneljasonxing@gmail.com
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Yushan Zhou <katrinzhou@tencent.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The comment above buffer mentions sign, 10 bytes width for number and null
terminator, but buffer itself isn't large enough to hold that much data.
This is a cosmetic change, since PID cannot be negative, other than -1.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Link: https://lore.kernel.org/20250617152110.2530-1-a.sadovnikov@ispras.ru
Signed-off-by: Artem Sadovnikov <a.sadovnikov@ispras.ru>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Rewind persistent ring buffer pages which have been read in the previous
boot. Those pages are highly possible to be lost before writing it to the
disk if the previous kernel crashed. In this case, the trace data is kept
on the persistent ring buffer, but it can not be read because its commit
size has been reset after read. This skips clearing the commit size of
each sub-buffer and recover it after reboot.
Note: If you read the previous boot data via trace_pipe, that is not
accessible in that time. But reboot without clearing (or reusing) the read
data, the read data is recovered again in the next boot.
Thus, when you read the previous boot data, clear it by `echo > trace`.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/174899582116.955054.773265393511190051.stgit@mhiramat.tok.corp.google.com
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Each RV monitor has one static buffer to send to the reactors. If multiple
errors are detected simultaneously, the one buffer could be overwritten.
Instead, leave it to the reactors to handle buffering.
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
A CPU mask on the stack is broken for large values of CONFIG_NR_CPUS:
kernel/trace/preemptirq_delay_test.c: In function ‘preemptirq_delay_run’:
kernel/trace/preemptirq_delay_test.c:143:1: error: the frame size of 8512 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]
Fall back to dynamic allocation here.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Song Chen <chensong_2000@189.cn>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250620111215.3365305-1-arnd@kernel.org
Fixes: 4b9091e1c1 ("kernel: trace: preemptirq_delay_test: add cpu affinity")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Freeing of filters requires to wait for both an RCU grace period as well as
a RCU task trace wait period after they have been detached from their
lists. The trace task period can be quite large so the freeing of the
filters was moved to use the call_rcu*() routines. The problem with that is
that the callback functions of call_rcu*() is done from a soft irq and can
cause latencies if the callback takes a bit of time.
The filters are freed per event in a system and the syscalls system
contains an event per system call, which can be over 700 events. Freeing 700
filters in a bottom half is undesirable.
Instead, move the freeing to use queue_rcu_work() which is done in task
context.
Link: https://lore.kernel.org/all/9a2f0cd0-1561-4206-8966-f93ccd25927f@paulmck-laptop/
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250609131732.04fd303b@gandalf.local.home
Fixes: a9d0aab5eb ("tracing: Fix regression of filter waiting a long time on RCU synchronization")
Suggested-by: "Paul E. McKenney" <paulmck@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Alexei suggested, 'link_type' can be more precise and differentiate
for human in fdinfo. In fact BPF_LINK_TYPE_KPROBE_MULTI includes
kretprobe_multi type, the same as BPF_LINK_TYPE_UPROBE_MULTI, so we
can show it more concretely.
link_type: kprobe_multi
link_id: 1
prog_tag: d2b307e915f0dd37
...
link_type: kretprobe_multi
link_id: 2
prog_tag: ab9ea0545870781d
...
link_type: uprobe_multi
link_id: 9
prog_tag: e729f789e34a8eca
...
link_type: uretprobe_multi
link_id: 10
prog_tag: 7db356c03e61a4d4
Co-developed-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Link: https://lore.kernel.org/r/20250702153958.639852-1-chen.dylane@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
As same as fprobe, register tracepoint stub function only when enabling
tprobe events. The major changes are introducing a list of
tracepoint_user and its lock, and tprobe_event_module_nb, which is
another module notifier for module loading/unloading. By spliting the
lock from event_mutex and a module notifier for trace_fprobe, it
solved AB-BA lock dependency issue between event_mutex and
tracepoint_module_list_mutex.
Link: https://lore.kernel.org/all/174343538901.843280.423773753642677941.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cleanup __store_entry_arg() so that it is easier to understand.
The main complexity may come from combining the loops for finding
stored-entry-arg and max-offset and appending new entry.
This split those different loops into 3 parts, lookup the same
entry-arg, find the max offset and append new entry.
Link: https://lore.kernel.org/all/174323039929.348535.4705349977127704120.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cross-merge BPF, perf and other fixes after downstream PRs.
It restores BPF CI to green after critical fix
commit bc4394e5e7 ("perf: Fix the throttle error of some clock events")
No conflicts.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The underlying lookup_user_key() function uses a signed 32 bit integer
for key serial numbers because legitimate serial numbers are positive
(and > 3) and keyrings are negative. Using a u32 for the keyring in
the bpf function doesn't currently cause any conversion problems but
will start to trip the signed to unsigned conversion warnings when the
kernel enables them, so convert the argument to signed (and update the
tests accordingly) before it acquires more users.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Link: https://lore.kernel.org/r/84cdb0775254d297d75e21f577089f64abdfbd28.camel@HansenPartnership.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull more tracing fixes from Steven Rostedt:
- Fix regression of waiting a long time on updating trace event filters
When the faultable trace points were added, it needed task trace RCU
synchronization.
This was added to the tracepoint_synchronize_unregister() function.
The filter logic always called this function whenever it updated the
trace event filters before freeing the old filters. This increased
the time of "trace-cmd record" from taking 13 seconds to running over
2 minutes to complete.
Move the freeing of the filters to call_rcu*() logic, which brings
the time back down to 13 seconds.
- Fix ring_buffer_subbuf_order_set() error path lock protection
The error path of the ring_buffer_subbuf_order_set() released the
mutex too early and allowed subsequent accesses to setting the
subbuffer size to corrupt the data and cause a bug.
By moving the mutex locking to the end of the error path, it prevents
the reentrant access to the critical data and also allows the
function to convert the taking of the mutex over to the guard()
logic.
- Remove unused power management clock events
The clock events were added in 2010 for power management. In 2011 arm
used them. In 2013 the code they were used in was removed. These
events have been wasting memory since then.
- Fix sparse warnings
There was a few places that sparse warned about trace_events_filter.c
where file->filter was referenced directly, but it is annotated with
an __rcu tag. Use the helper functions and fix them up to use
rcu_dereference() properly.
* tag 'trace-v6.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Add rcu annotation around file->filter accesses
tracing: PM: Remove unused clock events
ring-buffer: Fix buffer locking in ring_buffer_subbuf_order_set()
tracing: Fix regression of filter waiting a long time on RCU synchronization
Pull RISC-V updates from Palmer Dabbelt:
- Support for the FWFT SBI extension, which is part of SBI 3.0 and a
dependency for many new SBI and ISA extensions
- Support for getrandom() in the VDSO
- Support for mseal
- Optimized routines for raid6 syndrome and recovery calculations
- kexec_file() supports loading Image-formatted kernel binaries
- Improvements to the instruction patching framework to allow for
atomic instruction patching, along with rules as to how systems need
to behave in order to function correctly
- Support for a handful of new ISA extensions: Svinval, Zicbop, Zabha,
some SiFive vendor extensions
- Various fixes and cleanups, including: misaligned access handling,
perf symbol mangling, module loading, PUD THPs, and improved uaccess
routines
* tag 'riscv-for-linus-6.16-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (69 commits)
riscv: uaccess: Only restore the CSR_STATUS SUM bit
RISC-V: vDSO: Wire up getrandom() vDSO implementation
riscv: enable mseal sysmap for RV64
raid6: Add RISC-V SIMD syndrome and recovery calculations
riscv: mm: Add support for Svinval extension
RISC-V: Documentation: Add enough title underlines to CMODX
riscv: Improve Kconfig help for RISCV_ISA_V_PREEMPTIVE
MAINTAINERS: Update Atish's email address
riscv: uaccess: do not do misaligned accesses in get/put_user()
riscv: process: use unsigned int instead of unsigned long for put_user()
riscv: make unsafe user copy routines use existing assembly routines
riscv: hwprobe: export Zabha extension
riscv: Make regs_irqs_disabled() more clear
perf symbols: Ignore mapping symbols on riscv
RISC-V: Kconfig: Fix help text of CMDLINE_EXTEND
riscv: module: Optimize PLT/GOT entry counting
riscv: Add support for PUD THP
riscv: xchg: Prefetch the destination word for sc.w
riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop
riscv: Add support for Zicbop
...
When faultable trace events were added, a trace event may no longer use
normal RCU to synchronize but instead used synchronize_rcu_tasks_trace().
This synchronization takes a much longer time to synchronize.
The filter logic would free the filters by calling
tracepoint_synchronize_unregister() after it unhooked the filter strings
and before freeing them. With this function now calling
synchronize_rcu_tasks_trace() this increased the time to free a filter
tremendously. On a PREEMPT_RT system, it was even more noticeable.
# time trace-cmd record -p function sleep 1
[..]
real 2m29.052s
user 0m0.244s
sys 0m20.136s
As trace-cmd would clear out all the filters before recording, it could
take up to 2 minutes to do a recording of "sleep 1".
To find out where the issues was:
~# trace-cmd sqlhist -e -n sched_stack select start.prev_state as state, end.next_comm as comm, TIMESTAMP_DELTA_USECS as delta, start.STACKTRACE as stack from sched_switch as start join sched_switch as end on start.prev_pid = end.next_pid
Which will produce the following commands (and -e will also execute them):
echo 's:sched_stack s64 state; char comm[16]; u64 delta; unsigned long stack[];' >> /sys/kernel/tracing/dynamic_events
echo 'hist:keys=prev_pid:__arg_18057_2=prev_state,__arg_18057_4=common_timestamp.usecs,__arg_18057_7=common_stacktrace' >> /sys/kernel/tracing/events/sched/sched_switch/trigger
echo 'hist:keys=next_pid:__state_18057_1=$__arg_18057_2,__comm_18057_3=next_comm,__delta_18057_5=common_timestamp.usecs-$__arg_18057_4,__stack_18057_6=$__arg_18057_7:onmatch(sched.sched_switch).trace(sched_stack,$__state_18057_1,$__comm_18057_3,$__delta_18057_5,$__stack_18057_6)' >> /sys/kernel/tracing/events/sched/sched_switch/trigger
The above creates a synthetic event that creates a stack trace when a task
schedules out and records it with the time it scheduled back in. Basically
the time a task is off the CPU. It also records the state of the task when
it left the CPU (running, blocked, sleeping, etc). It also saves the comm
of the task as "comm" (needed for the next command).
~# echo 'hist:keys=state,stack.stacktrace:vals=delta:sort=state,delta if comm == "trace-cmd" && state & 3' > /sys/kernel/tracing/events/synthetic/sched_stack/trigger
The above creates a histogram with buckets per state, per stack, and the
value of the total time it was off the CPU for that stack trace. It filters
on tasks with "comm == trace-cmd" and only the sleeping and blocked states
(1 - sleeping, 2 - blocked).
~# trace-cmd record -p function sleep 1
~# cat /sys/kernel/tracing/events/synthetic/sched_stack/hist | tail -18
{ state: 2, stack.stacktrace __schedule+0x1545/0x3700
schedule+0xe2/0x390
schedule_timeout+0x175/0x200
wait_for_completion_state+0x294/0x440
__wait_rcu_gp+0x247/0x4f0
synchronize_rcu_tasks_generic+0x151/0x230
apply_subsystem_event_filter+0xa2b/0x1300
subsystem_filter_write+0x67/0xc0
vfs_write+0x1e2/0xeb0
ksys_write+0xff/0x1d0
do_syscall_64+0x7b/0x420
entry_SYSCALL_64_after_hwframe+0x76/0x7e
} hitcount: 237 delta: 99756288 <<--------------- Delta is 99 seconds!
Totals:
Hits: 525
Entries: 21
Dropped: 0
This shows that this particular trace waited for 99 seconds on
synchronize_rcu_tasks() in apply_subsystem_event_filter().
In fact, there's a lot of places in the filter code that spends a lot of
time waiting for synchronize_rcu_tasks_trace() in order to free the
filters.
Add helper functions that will use call_rcu*() variants to asynchronously
free the filters. This brings the timings back to normal:
# time trace-cmd record -p function sleep 1
[..]
real 0m14.681s
user 0m0.335s
sys 0m28.616s
And the histogram also shows this:
~# cat /sys/kernel/tracing/events/synthetic/sched_stack/hist | tail -21
{ state: 2, stack.stacktrace __schedule+0x1545/0x3700
schedule+0xe2/0x390
schedule_timeout+0x175/0x200
wait_for_completion_state+0x294/0x440
__wait_rcu_gp+0x247/0x4f0
synchronize_rcu_normal+0x3db/0x5c0
tracing_reset_online_cpus+0x8f/0x1e0
tracing_open+0x335/0x440
do_dentry_open+0x4c6/0x17a0
vfs_open+0x82/0x360
path_openat+0x1a36/0x2990
do_filp_open+0x1c5/0x420
do_sys_openat2+0xed/0x180
__x64_sys_openat+0x108/0x1d0
do_syscall_64+0x7b/0x420
} hitcount: 2 delta: 77044
Totals:
Hits: 55
Entries: 28
Dropped: 0
Where the total waiting time of synchronize_rcu_tasks_trace() is 77
milliseconds.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Andreas Ziegler <ziegler.andreas@siemens.com>
Cc: Felix MOESSBAUER <felix.moessbauer@siemens.com>
Link: https://lore.kernel.org/20250606201936.1e3d09a9@batman.local.home
Reported-by: "Flot, Julien" <julien.flot@siemens.com>
Tested-by: Julien Flot <julien.flot@siemens.com>
Fixes: a363d27cdb ("tracing: Allow system call tracepoints to handle page faults")
Closes: https://lore.kernel.org/all/240017f656631c7dd4017aa93d91f41f653788ea.camel@siemens.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
riscv patches for 6.16-rc1, part 2
* Performance improvements
- Add support for vdso getrandom
- Implement raid6 calculations using vectors
- Introduce svinval tlb invalidation
* Cleanup
- A bunch of deduplication of the macros we use for manipulating instructions
* Misc
- Introduce a kunit test for kprobes
- Add support for mseal as riscv fits the requirements (thanks to Lorenzo for making sure of that :))
[Palmer: There was a rebase between part 1 and part 2, so I've had to do
some more git surgery here... at least two rounds of surgery...]
* alex-pr-2: (866 commits)
RISC-V: vDSO: Wire up getrandom() vDSO implementation
riscv: enable mseal sysmap for RV64
raid6: Add RISC-V SIMD syndrome and recovery calculations
riscv: mm: Add support for Svinval extension
riscv: Add kprobes KUnit test
riscv: kprobes: Remove duplication of RV_EXTRACT_ITYPE_IMM
riscv: kprobes: Remove duplication of RV_EXTRACT_UTYPE_IMM
riscv: kprobes: Remove duplication of RV_EXTRACT_RD_REG
riscv: kprobes: Remove duplication of RVC_EXTRACT_BTYPE_IMM
riscv: kprobes: Remove duplication of RVC_EXTRACT_C2_RS1_REG
riscv: kproves: Remove duplication of RVC_EXTRACT_JTYPE_IMM
riscv: kprobes: Remove duplication of RV_EXTRACT_BTYPE_IMM
riscv: kprobes: Remove duplication of RV_EXTRACT_RS1_REG
riscv: kprobes: Remove duplication of RV_EXTRACT_JTYPE_IMM
riscv: kprobes: Move branch_funct3 to insn.h
riscv: kprobes: Move branch_rs2_idx to insn.h
Linux 6.15-rc6
Input: xpad - fix xpad_device sorting
Input: xpad - add support for several more controllers
Input: xpad - fix Share button on Xbox One controllers
...
The following ftrace patch for riscv uses a data store to update ftrace
function. Therefore, a romote fence is required to order it against
function_trace_op updates. The mechanism is similar to the fence between
function_trace_op and update_ftrace_func in the generic ftrace, so we
leverage the same ftrace_sync_ipi function.
[ alex: Fix build warning when !CONFIG_DYNAMIC_FTRACE ]
Signed-off-by: Andy Chiu <andybnac@gmail.com>
Link: https://lore.kernel.org/r/20250407180838.42877-4-andybnac@gmail.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
The following issue happens with a buggy module:
BUG: unable to handle page fault for address: ffffffffc05d0218
PGD 1bd66f067 P4D 1bd66f067 PUD 1bd671067 PMD 101808067 PTE 0
Oops: Oops: 0000 [#1] SMP KASAN PTI
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
RIP: 0010:sized_strscpy+0x81/0x2f0
RSP: 0018:ffff88812d76fa08 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffc0601010 RCX: dffffc0000000000
RDX: 0000000000000038 RSI: dffffc0000000000 RDI: ffff88812608da2d
RBP: 8080808080808080 R08: ffff88812608da2d R09: ffff88812608da68
R10: ffff88812608d82d R11: ffff88812608d810 R12: 0000000000000038
R13: ffff88812608da2d R14: ffffffffc05d0218 R15: fefefefefefefeff
FS: 00007fef552de740(0000) GS:ffff8884251c7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffc05d0218 CR3: 00000001146f0000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ftrace_mod_get_kallsym+0x1ac/0x590
update_iter_mod+0x239/0x5b0
s_next+0x5b/0xa0
seq_read_iter+0x8c9/0x1070
seq_read+0x249/0x3b0
proc_reg_read+0x1b0/0x280
vfs_read+0x17f/0x920
ksys_read+0xf3/0x1c0
do_syscall_64+0x5f/0x2e0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The above issue may happen as follows:
(1) Add kprobe tracepoint;
(2) insmod test.ko;
(3) Module triggers ftrace disabled;
(4) rmmod test.ko;
(5) cat /proc/kallsyms; --> Will trigger UAF as test.ko already removed;
ftrace_mod_get_kallsym()
...
strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
...
The problem is when a module triggers an issue with ftrace and
sets ftrace_disable. The ftrace_disable is set when an anomaly is
discovered and to prevent any more damage, ftrace stops all text
modification. The issue that happened was that the ftrace_disable stops
more than just the text modification.
When a module is loaded, its init functions can also be traced. Because
kallsyms deletes the init functions after a module has loaded, ftrace
saves them when the module is loaded and function tracing is enabled. This
allows the output of the function trace to show the init function names
instead of just their raw memory addresses.
When a module is removed, ftrace_release_mod() is called, and if
ftrace_disable is set, it just returns without doing anything more. The
problem here is that it leaves the mod_list still around and if kallsyms
is called, it will call into this code and access the module memory that
has already been freed as it will return:
strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
Where the "mod" no longer exists and triggers a UAF bug.
Link: https://lore.kernel.org/all/20250523135452.626d8dcd@gandalf.local.home/
Cc: stable@vger.kernel.org
Fixes: aba4b5c22c ("ftrace: Save module init functions kallsyms symbols for tracing")
Link: https://lore.kernel.org/20250529111955.2349189-2-yebin@huaweicloud.com
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
