The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
[ neeraj.upadhyay: Fix htmldocs build error reported by Stephen Rothwell ]
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.
[ neeraj.upadhyay: Fix htmldocs build error reported by Stephen Rothwell ]
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Pull dma-mapping fix from Christoph Hellwig:
- avoid a deadlock with dma-debug and netconsole (Rik van Riel)
* tag 'dma-mapping-6.11-2024-08-10' of git://git.infradead.org/users/hch/dma-mapping:
dma-debug: avoid deadlock between dma debug vs printk and netconsole
Devices can provide multiple interrupt lines. One reason for this is that
a device has multiple subfunctions, each providing its own interrupt line.
Another reason is that a device can be designed to be used (also) on a
system where some of the interrupts can be routed to another processor.
A line often further acts as a demultiplex for specific interrupts
and has it's respective set of interrupt (status, mask, ack, ...)
registers.
Regmap supports the handling of these registers and demultiplexing
interrupts, but the interrupt domain code ends up assigning the same name
for the per interrupt line domains. This causes a naming collision in the
debugFS code and leads to confusion, as /proc/interrupts shows two separate
interrupts with the same domain name and hardware interrupt number.
Instead of adding a workaround in regmap or driver code, allow giving a
name suffix for the domain name when the domain is created.
Add a name_suffix field in the irq_domain_info structure and make
irq_domain_instantiate() use this suffix if it is given when a domain is
created.
[ tglx: Adopt it to the cleanup patch and fixup the invalid NULL return ]
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/871q2yvk5x.ffs@tglx
irq_domain_create_simple() and irq_domain_create_legacy() use
__irq_domain_instantiate(), but have extra handling of allocating interrupt
descriptors and associating interrupts in them. Some of that is duplicated.
There are also call sites which have conditonals to invoke different
interrupt domain creator functions, where one of them is usually
irq_domain_create_legacy(). Alternatively they associate the interrupts for
the legacy case after creating the domain.
Moving the extra logic of irq_domain_create_simple()/legacy() into
__irq_domain_instantiate() allows to consolidate that.
Introduce hwirq_base and virq_base members in the irq_domain_info
structure, which allows to transport the required information and add the
conditional interrupt descriptor allocation and interrupt association into
__irq_domain_instantiate().
This reduces irq_domain_create_legacy() and irq_domain_create_simple() to
trivial wrappers which fill in the info structure and allows call sites
which must support the legacy case along with more modern mechanism to
select the domain type via the parameters of the info struct.
[ tglx: Massaged change log ]
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/32d07bd79eb2b5416e24da9e9e8fe5955423dcf9.1723120028.git.mazziesaccount@gmail.com
When running the following:
# cd /sys/kernel/tracing/
# echo 1 > events/sched/sched_waking/enable
# echo 1 > events/sched/sched_switch/enable
# echo 0 > tracing_on
# dd if=per_cpu/cpu0/trace_pipe_raw of=/tmp/raw0.dat
The dd task would get stuck in an infinite loop in the kernel. What would
happen is the following:
When ring_buffer_read_page() returns -1 (no data) then a check is made to
see if the buffer is empty (as happens when the page is not full), it will
call wait_on_pipe() to wait until the ring buffer has data. When it is it
will try again to read data (unless O_NONBLOCK is set).
The issue happens when there's a reader and the file descriptor is closed.
The wait_on_pipe() will return when that is the case. But this loop will
continue to try again and wait_on_pipe() will again return immediately and
the loop will continue and never stop.
Simply check if the file was closed before looping and exit out if it is.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240808235730.78bf63e5@rorschach.local.home
Fixes: 2aa043a55b ("tracing/ring-buffer: Fix wait_on_pipe() race")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Pull kprobe fixes from Masami Hiramatsu:
- Fix misusing str_has_prefix() parameter order to check symbol prefix
correctly
- bpf: remove unused declaring of bpf_kprobe_override
* tag 'probes-fixes-v6.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
kprobes: Fix to check symbol prefixes correctly
bpf: kprobe: remove unused declaring of bpf_kprobe_override
It turns out that the WARN_ON_ONCE() call in css_release_work_fn
introduced by commit ab03125268 ("cgroup: Show # of subsystem CSSes
in cgroup.stat") is incorrect. Although css->nr_descendants must be
0 when a css is released and ready to be freed, the corresponding
cgrp->nr_dying_subsys[ss->id] may not be 0 if a subsystem is activated
and deactivated multiple times with one or more of its previous
activation leaving behind dying csses.
Fix the incorrect warning by removing the cgrp->nr_dying_subsys check.
Fixes: ab03125268 ("cgroup: Show # of subsystem CSSes in cgroup.stat")
Closes: https://lore.kernel.org/cgroups/6f301773-2fce-4602-a391-8af7ef00b2fb@redhat.com/T/#t
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The recursive aes-arm-bs module load situation reported by Russell King
is getting fixed in the crypto layer, but this in the meantime fixes the
"recursive load hangs forever" by just making the waiting for the first
module load be interruptible.
This should now match the old behavior before commit 9b9879fc03
("modules: catch concurrent module loads, treat them as idempotent"),
which used the different "wait for module to be ready" code in
module_patient_check_exists().
End result: a recursive module load will still block, but now a signal
will interrupt it and fail the second module load, at which point the
first module will successfully complete loading.
Fixes: 9b9879fc03 ("modules: catch concurrent module loads, treat them as idempotent")
Cc: Russell King <linux@armlinux.org.uk>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sched_ext currently doesn't generate messages when the BPF scheduler is
enabled and disabled unless there are errors. It is useful to have paper
trail. Improve logging around enable/disable:
- Generate info messages on enable and non-error disable.
- Update error exit message formatting so that it's consistent with
non-error message. Also, prefix ei->msg with the BPF scheduler's name to
make it clear where the message is coming from.
- Shorten scx_exit_reason() strings for SCX_EXIT_UNREG* for brevity and
consistency.
v2: Use pr_*() instead of KERN_* consistently. (David)
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Phil Auld <pauld@redhat.com>
Acked-by: David Vernet <void@manifault.com>
scx_rq_online() currently only tests SCX_RQ_ONLINE. This isn't fully correct
- e.g. consume_dispatch_q() uses task_run_on_remote_rq() which tests
scx_rq_online() to see whether the current rq can run the task, and, if so,
calls consume_remote_task() to migrate the task to @rq. While the test
itself was done while locking @rq, @rq can be temporarily unlocked by
consume_remote_task() and nothing prevents SCX_RQ_ONLINE from going offline
before the migration takes place.
To address the issue, add cpu_active() test to scx_rq_online(). There is a
synchronize_rcu() between cpu_active() being cleared and the rq going
offline, so if an on-going scheduling operation sees cpu_active(), the
associated rq is guaranteed to not go offline until the scheduling operation
is complete.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 60c27fb59f ("sched_ext: Implement sched_ext_ops.cpu_online/offline()")
Acked-by: David Vernet <void@manifault.com>
process_ddsp_deferred_locals() executes deferred direct dispatches to the
local DSQs of remote CPUs. It iterates the tasks on
rq->scx.ddsp_deferred_locals list, removing and calling
dispatch_to_local_dsq() on each. However, the list is protected by the rq
lock that can be dropped by dispatch_to_local_dsq() temporarily, so the list
can be modified during the iteration, which can lead to oopses and other
failures.
Fix it by popping from the head of the list instead of iterating the list.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 5b26f7b920 ("sched_ext: Allow SCX_DSQ_LOCAL_ON for direct dispatches")
Acked-by: David Vernet <void@manifault.com>
Pull tracing fixes from Steven Rostedt:
- Have reading of event format files test if the metadata still exists.
When a event is freed, a flag (EVENT_FILE_FL_FREED) in the metadata
is set to state that it is to prevent any new references to it from
happening while waiting for existing references to close. When the
last reference closes, the metadata is freed. But the "format" was
missing a check to this flag (along with some other files) that
allowed new references to happen, and a use-after-free bug to occur.
- Have the trace event meta data use the refcount infrastructure
instead of relying on its own atomic counters.
- Have tracefs inodes use alloc_inode_sb() for allocation instead of
using kmem_cache_alloc() directly.
- Have eventfs_create_dir() return an ERR_PTR instead of NULL as the
callers expect a real object or an ERR_PTR.
- Have release_ei() use call_srcu() and not call_rcu() as all the
protection is on SRCU and not RCU.
- Fix ftrace_graph_ret_addr() to use the task passed in and not
current.
- Fix overflow bug in get_free_elt() where the counter can overflow the
integer and cause an infinite loop.
- Remove unused function ring_buffer_nr_pages()
- Have tracefs freeing use the inode RCU infrastructure instead of
creating its own.
When the kernel had randomize structure fields enabled, the rcu field
of the tracefs_inode was overlapping the rcu field of the inode
structure, and corrupting it. Instead, use the destroy_inode()
callback to do the initial cleanup of the code, and then have
free_inode() free it.
* tag 'trace-v6.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracefs: Use generic inode RCU for synchronizing freeing
ring-buffer: Remove unused function ring_buffer_nr_pages()
tracing: Fix overflow in get_free_elt()
function_graph: Fix the ret_stack used by ftrace_graph_ret_addr()
eventfs: Use SRCU for freeing eventfs_inodes
eventfs: Don't return NULL in eventfs_create_dir()
tracefs: Fix inode allocation
tracing: Use refcount for trace_event_file reference counter
tracing: Have format file honor EVENT_FILE_FL_FREED
Pull bcachefs fixes from Kent Overstreet:
"Assorted little stuff:
- lockdep fixup for lockdep_set_notrack_class()
- we can now remove a device when using erasure coding without
deadlocking, though we still hit other issues
- the 'allocator stuck' timeout is now configurable, and messages are
ratelimited. The default timeout has been increased from 10 seconds
to 30"
* tag 'bcachefs-2024-08-08' of git://evilpiepirate.org/bcachefs:
bcachefs: Use bch2_wait_on_allocator() in btree node alloc path
bcachefs: Make allocator stuck timeout configurable, ratelimit messages
bcachefs: Add missing path_traverse() to btree_iter_next_node()
bcachefs: ec should not allocate from ro devs
bcachefs: Improved allocator debugging for ec
bcachefs: Add missing bch2_trans_begin() call
bcachefs: Add a comment for bucket helper types
bcachefs: Don't rely on implicit unsigned -> signed integer conversion
lockdep: Fix lockdep_set_notrack_class() for CONFIG_LOCK_STAT
bcachefs: Fix double free of ca->buckets_nouse
Russell King reported that the arm cbc(aes) crypto module hangs when
loaded, and Herbert Xu bisected it to commit 9b9879fc03 ("modules:
catch concurrent module loads, treat them as idempotent"), and noted:
"So what's happening here is that the first modprobe tries to load a
fallback CBC implementation, in doing so it triggers a load of the
exact same module due to module aliases.
IOW we're loading aes-arm-bs which provides cbc(aes). However, this
needs a fallback of cbc(aes) to operate, which is made out of the
generic cbc module + any implementation of aes, or ecb(aes). The
latter happens to also be provided by aes-arm-cb so that's why it
tries to load the same module again"
So loading the aes-arm-bs module ends up wanting to recursively load
itself, and the recursive load then ends up waiting for the original
module load to complete.
This is a regression, in that it used to be that we just tried to load
the module multiple times, and then as we went on to install it the
second time we would instead just error out because the module name
already existed.
That is actually also exactly what the original "catch concurrent loads"
patch did in commit 9828ed3f69 ("module: error out early on concurrent
load of the same module file"), but it turns out that it ends up being
racy, in that erroring out before the module has been fully initialized
will cause failures in dependent module loading.
See commit ac2263b588 (which was the revert of that "error out early")
commit for details about why erroring out before the module has been
initialized is actually fundamentally racy.
Now, for the actual recursive module load (as opposed to just
concurrently loading the same module twice), the race is not an issue.
At the same time it's hard for the kernel to see that this is recursion,
because the module load is always done from a usermode helper, so the
recursion is not some simple callchain within the kernel.
End result: this is not the real fix, but this at least adds a warning
for the situation (admittedly much too late for all the debugging pain
that Russell and Herbert went through) and if we can come to a
resolution on how to detect the recursion properly, this re-organizes
the code to make that easier.
Link: https://lore.kernel.org/all/ZrFHLqvFqhzykuYw@shell.armlinux.org.uk/
Reported-by: Russell King <linux@armlinux.org.uk>
Debugged-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a boot self test that can catch sprious coverage from interrupts.
The coverage callback filters out interrupt code, but only after the
handler updates preempt count. Some code periodically leaks out
of that section and leads to spurious coverage.
Add a best-effort (but simple) test that is likely to catch such bugs.
If the test is enabled on CI systems that use KCOV, they should catch
any issues fast.
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/all/7662127c97e29da1a748ad1c1539dd7b65b737b2.1718092070.git.dvyukov@google.com
Pull misc fixes from Andrew Morton:
"Nine hotfixes. Five are cc:stable, the others either pertain to
post-6.10 material or aren't considered necessary for earlier kernels.
Five are MM and four are non-MM. No identifiable theme here - please
see the individual changelogs"
* tag 'mm-hotfixes-stable-2024-08-07-18-32' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
padata: Fix possible divide-by-0 panic in padata_mt_helper()
mailmap: update entry for David Heidelberg
memcg: protect concurrent access to mem_cgroup_idr
mm: shmem: fix incorrect aligned index when checking conflicts
mm: shmem: avoid allocating huge pages larger than MAX_PAGECACHE_ORDER for shmem
mm: list_lru: fix UAF for memory cgroup
kcov: properly check for softirq context
MAINTAINERS: Update LTP members and web
selftests: mm: add s390 to ARCH check
Many of the the context reschedule users are of the form:
ctx_sched_out(.type = EVENT_TIME);
... modify context
ctx_resched();
With the idea that the whole reschedule happens with a single
time-stamp, rather than with each ctx_sched_out() advancing time and
ctx_sched_in() re-starting time, creating a non-atomic experience.
However, Kan noticed that since this completely stops time, it
actually looses a bit of time between the stop and start. Worse, now
that we can do partial (per PMU) reschedules, the PMUs that are not
scheduled out still observe the time glitch.
Replace this with:
ctx_time_freeze();
... modify context
ctx_resched();
With the assumption that this happens in a perf_ctx_lock() /
perf_ctx_unlock() pair.
The new ctx_time_freeze() will update time and sets EVENT_FROZEN, and
ensures EVENT_TIME and EVENT_FROZEN remain set, this avoids
perf_event_time_now() from observing a time wobble from not seeing
EVENT_TIME for a little while.
Additionally, this avoids loosing time between
ctx_sched_out(EVENT_TIME) and ctx_sched_in(), which would re-set the
timestamp.
Reported-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240807115550.250637571@infradead.org
Currently re-scheduling a context will reschedule all active PMUs for
that context, even if it is known only a single event is added.
Namhyung reported that changing this to only reschedule the affected
PMU when possible provides significant performance gains under certain
conditions.
Therefore, allow partial context reschedules for a specific PMU, that
of the event modified.
While the patch looks somewhat noisy, it mostly just propagates a new
@pmu argument through the callchain and modifies the epc loop to only
pick the 'epc->pmu == @pmu' case.
Reported-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240807115549.920950699@infradead.org
We are hit with a not easily reproducible divide-by-0 panic in padata.c at
bootup time.
[ 10.017908] Oops: divide error: 0000 1 PREEMPT SMP NOPTI
[ 10.017908] CPU: 26 PID: 2627 Comm: kworker/u1666:1 Not tainted 6.10.0-15.el10.x86_64 #1
[ 10.017908] Hardware name: Lenovo ThinkSystem SR950 [7X12CTO1WW]/[7X12CTO1WW], BIOS [PSE140J-2.30] 07/20/2021
[ 10.017908] Workqueue: events_unbound padata_mt_helper
[ 10.017908] RIP: 0010:padata_mt_helper+0x39/0xb0
:
[ 10.017963] Call Trace:
[ 10.017968] <TASK>
[ 10.018004] ? padata_mt_helper+0x39/0xb0
[ 10.018084] process_one_work+0x174/0x330
[ 10.018093] worker_thread+0x266/0x3a0
[ 10.018111] kthread+0xcf/0x100
[ 10.018124] ret_from_fork+0x31/0x50
[ 10.018138] ret_from_fork_asm+0x1a/0x30
[ 10.018147] </TASK>
Looking at the padata_mt_helper() function, the only way a divide-by-0
panic can happen is when ps->chunk_size is 0. The way that chunk_size is
initialized in padata_do_multithreaded(), chunk_size can be 0 when the
min_chunk in the passed-in padata_mt_job structure is 0.
Fix this divide-by-0 panic by making sure that chunk_size will be at least
1 no matter what the input parameters are.
Link: https://lkml.kernel.org/r/20240806174647.1050398-1-longman@redhat.com
Fixes: 004ed42638 ("padata: add basic support for multithreaded jobs")
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Waiman Long <longman@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When collecting coverage from softirqs, KCOV uses in_serving_softirq() to
check whether the code is running in the softirq context. Unfortunately,
in_serving_softirq() is > 0 even when the code is running in the hardirq
or NMI context for hardirqs and NMIs that happened during a softirq.
As a result, if a softirq handler contains a remote coverage collection
section and a hardirq with another remote coverage collection section
happens during handling the softirq, KCOV incorrectly detects a nested
softirq coverate collection section and prints a WARNING, as reported by
syzbot.
This issue was exposed by commit a7f3813e58 ("usb: gadget: dummy_hcd:
Switch to hrtimer transfer scheduler"), which switched dummy_hcd to using
hrtimer and made the timer's callback be executed in the hardirq context.
Change the related checks in KCOV to account for this behavior of
in_serving_softirq() and make KCOV ignore remote coverage collection
sections in the hardirq and NMI contexts.
This prevents the WARNING printed by syzbot but does not fix the inability
of KCOV to collect coverage from the __usb_hcd_giveback_urb when dummy_hcd
is in use (caused by a7f3813e58); a separate patch is required for that.
Link: https://lkml.kernel.org/r/20240729022158.92059-1-andrey.konovalov@linux.dev
Fixes: 5ff3b30ab5 ("kcov: collect coverage from interrupts")
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reported-by: syzbot+2388cdaeb6b10f0c13ac@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2388cdaeb6b10f0c13ac
Acked-by: Marco Elver <elver@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Aleksandr Nogikh <nogikh@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marcello Sylvester Bauer <sylv@sylv.io>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
"tracing_map->next_elt" in get_free_elt() is at risk of overflowing.
Once it overflows, new elements can still be inserted into the tracing_map
even though the maximum number of elements (`max_elts`) has been reached.
Continuing to insert elements after the overflow could result in the
tracing_map containing "tracing_map->max_size" elements, leaving no empty
entries.
If any attempt is made to insert an element into a full tracing_map using
`__tracing_map_insert()`, it will cause an infinite loop with preemption
disabled, leading to a CPU hang problem.
Fix this by preventing any further increments to "tracing_map->next_elt"
once it reaches "tracing_map->max_elt".
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 08d43a5fa0 ("tracing: Add lock-free tracing_map")
Co-developed-by: Cheng-Jui Wang <cheng-jui.wang@mediatek.com>
Link: https://lore.kernel.org/20240805055922.6277-1-Tze-nan.Wu@mediatek.com
Signed-off-by: Cheng-Jui Wang <cheng-jui.wang@mediatek.com>
Signed-off-by: Tze-nan Wu <Tze-nan.Wu@mediatek.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When eventfs was introduced, special care had to be done to coordinate the
freeing of the file meta data with the files that are exposed to user
space. The file meta data would have a ref count that is set when the file
is created and would be decremented and freed after the last user that
opened the file closed it. When the file meta data was to be freed, it
would set a flag (EVENT_FILE_FL_FREED) to denote that the file is freed,
and any new references made (like new opens or reads) would fail as it is
marked freed. This allowed other meta data to be freed after this flag was
set (under the event_mutex).
All the files that were dynamically created in the events directory had a
pointer to the file meta data and would call event_release() when the last
reference to the user space file was closed. This would be the time that it
is safe to free the file meta data.
A shortcut was made for the "format" file. It's i_private would point to
the "call" entry directly and not point to the file's meta data. This is
because all format files are the same for the same "call", so it was
thought there was no reason to differentiate them. The other files
maintain state (like the "enable", "trigger", etc). But this meant if the
file were to disappear, the "format" file would be unaware of it.
This caused a race that could be trigger via the user_events test (that
would create dynamic events and free them), and running a loop that would
read the user_events format files:
In one console run:
# cd tools/testing/selftests/user_events
# while true; do ./ftrace_test; done
And in another console run:
# cd /sys/kernel/tracing/
# while true; do cat events/user_events/__test_event/format; done 2>/dev/null
With KASAN memory checking, it would trigger a use-after-free bug report
(which was a real bug). This was because the format file was not checking
the file's meta data flag "EVENT_FILE_FL_FREED", so it would access the
event that the file meta data pointed to after the event was freed.
After inspection, there are other locations that were found to not check
the EVENT_FILE_FL_FREED flag when accessing the trace_event_file. Add a
new helper function: event_file_file() that will make sure that the
event_mutex is held, and will return NULL if the trace_event_file has the
EVENT_FILE_FL_FREED flag set. Have the first reference of the struct file
pointer use event_file_file() and check for NULL. Later uses can still use
the event_file_data() helper function if the event_mutex is still held and
was not released since the event_file_file() call.
Link: https://lore.kernel.org/all/20240719204701.1605950-1-minipli@grsecurity.net/
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Ilkka Naulapää <digirigawa@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Alexey Makhalov <alexey.makhalov@broadcom.com>
Cc: Vasavi Sirnapalli <vasavi.sirnapalli@broadcom.com>
Link: https://lore.kernel.org/20240730110657.3b69d3c1@gandalf.local.home
Fixes: b63db58e2f ("eventfs/tracing: Add callback for release of an eventfs_inode")
Reported-by: Mathias Krause <minipli@grsecurity.net>
Tested-by: Mathias Krause <minipli@grsecurity.net>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
rt_task() checks if a task has RT priority. But depends on your
dictionary, this could mean it belongs to RT class, or is a 'realtime'
task, which includes RT and DL classes.
Since this has caused some confusion already on discussion [1], it
seemed a clean up is due.
I define the usage of rt_task() to be tasks that belong to RT class.
Make sure that it returns true only for RT class and audit the users and
replace the ones required the old behavior with the new realtime_task()
which returns true for RT and DL classes. Introduce similar
realtime_prio() to create similar distinction to rt_prio() and update
the users that required the old behavior to use the new function.
Move MAX_DL_PRIO to prio.h so it can be used in the new definitions.
Document the functions to make it more obvious what is the difference
between them. PI-boosted tasks is a factor that must be taken into
account when choosing which function to use.
Rename task_is_realtime() to realtime_task_policy() as the old name is
confusing against the new realtime_task().
No functional changes were intended.
[1] https://lore.kernel.org/lkml/20240506100509.GL40213@noisy.programming.kicks-ass.net/
Signed-off-by: Qais Yousef <qyousef@layalina.io>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240610192018.1567075-2-qyousef@layalina.io
Currently, whenever a caller is providing an affinity hint for an
interrupt, the allocation code uses it to calculate the node and copies the
cpumask into irq_desc::affinity.
If the affinity for the interrupt is not marked 'managed' then the startup
of the interrupt ignores irq_desc::affinity and uses the system default
affinity mask.
Prevent this by setting the IRQD_AFFINITY_SET flag for the interrupt in the
allocator, which causes irq_setup_affinity() to use irq_desc::affinity on
interrupt startup if the mask contains an online CPU.
[ tglx: Massaged changelog ]
Fixes: 45ddcecbfa ("genirq: Use affinity hint in irqdesc allocation")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/all/20240806072044.837827-1-shayd@nvidia.com
balance_fair() skips newidle balancing if rq->nr_running - there are already
tasks on the rq, so no need to try to pull tasks. This tests the total
number of queued tasks on the CPU instead of only the fair class, but is
still correct as the rq can currently only have fair class tasks while
balance_fair() is running.
However, with the addition of sched_ext below the fair class, this will not
hold anymore and make put_prev_task_balance() skip sched_ext's balance()
incorrectly as, when a CPU has only lower priority class tasks,
rq->nr_running would still be positive and balance_fair() would return 1
even when fair doesn't have any tasks to run.
Update balance_fair() to use sched_fair_runnable() which tests
rq->cfs.nr_running which is updated by bandwidth throttling. Note that
pick_next_task_fair() already uses sched_fair_runnable() in its optimized
path for the same purpose.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lore.kernel.org/r/ZrFUjlCf7x3TNXB8@slm.duckdns.org
When we want to debug the workqueue stall, we can immediately make
a panic to get the information we want.
In some systems, it may be necessary to quickly reboot the system to
escape from a workqueue lockup situation. In this case, we can control
the number of stall detections to generate panic.
workqueue.panic_on_stall sets the number times of the stall to trigger
panic. 0 disables the panic on stall.
Signed-off-by: Sangmoon Kim <sangmoon.kim@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
task_can_run_on_remote_rq() is similar to is_cpu_allowed() but there are
subtle differences. It currently open codes all the tests. This is
cumbersome to understand and error-prone in case the intersecting tests need
to be updated.
Factor out the common part - testing whether the task is allowed on the CPU
at all regardless of the CPU state - into task_allowed_on_cpu() and make
both is_cpu_allowed() and SCX's task_can_run_on_remote_rq() use it. As the
code is now linked between the two and each contains only the extra tests
that differ between them, it's less error-prone when the conditions need to
be updated. Also, improve the comment to explain why they are different.
v2: Replace accidental "extern inline" with "static inline" (Peter).
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David Vernet <void@manifault.com>
scx_task_iter_next_locked() skips tasks whose sched_class is
idle_sched_class. While it has a short comment explaining why it's testing
the sched_class directly isntead of using is_idle_task(), the comment
doesn't sufficiently explain what's going on and why. Improve the comment.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: David Vernet <void@manifault.com>
On SMP, SCX performs dispatch from sched_class->balance(). As balance() was
not available in UP, it instead called the internal balance function from
put_prev_task_scx() and pick_next_task_scx() to emulate the effect, which is
rather nasty.
Enabling sched_class->balance() on UP shouldn't cause any meaningful
overhead. Enable balance() on UP and drop the ugly workaround.
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David Vernet <void@manifault.com>
update_curr_scx() is open coding runtime updates. Use update_curr_common()
instead and avoid unnecessary deviations.
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David Vernet <void@manifault.com>
