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The attrs are where the affinity scope lives, and a per-cpu workqueue
will need one once per-cpu becomes a scope rather than a separate
backend. Allocate them unconditionally.
wq_dump.py used a non-NULL wq->attrs as its test for an unbound
workqueue, which no longer holds; test WQ_UNBOUND there instead.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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The unbound prefix says which workqueues currently have the field rather
than what it holds, and the next patch allocates it for every workqueue.
Rename it first so that change stays a single line.
tools/workqueue/wq_dump.py reads the field by name, so rename it there
too.
wq_sysfs_unbound_attrs[] keeps its name: it is the set of sysfs files
that only unbound workqueues expose.
No functional change.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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workqueue_online_cpu() and workqueue_offline_cpu() decide whether a
workqueue needs a pod affinity update by testing wq->unbound_attrs for
NULL, which is only meaningful because the attrs are allocated for
unbound workqueues alone.
Test the flag instead, so the attrs can later be allocated for every
workqueue.
No functional change.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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pwq_tryinc_nr_active() and pwq_dec_nr_active() choose between the shared
per-node nr_active and the plain per-pwq one by testing
wq_node_nr_active() for NULL.
Test the backing pool with is_percpu_pool() instead, so the accounting
follows the pool that runs the work rather than the workqueue type.
No functional change.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Add is_percpu_pool() and test the pool directly for per cpu. Convert the
other open-coded pool->cpu checks -- in put_unbound_pool(),
pool_allowed_cpus() and the workqueue watchdog -- to the same helper.
No functional change.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Move the per-cpu pwq allocation loop out of alloc_and_link_pwqs() into a
helper. The inner allocation-failure path now returns -ENOMEM and the
caller jumps to the existing enomem cleanup, equivalent to the previous
goto.
No functional change.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Move the static per-cpu worker_pool lookup in alloc_and_link_pwqs() into
a helper, get_percpu_pool(), so the lookup can be shared by other
pool-selection paths.
No functional change.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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If the auxiliary clock is disabled during tk_get_aux_ts64() but is enabled
before tks->clock_valid is checked, then uninitialized stackdata will be
used in the calculations and indirectly leaked to userspace.
The same race window also exists after this change and also for the core
timekeeper. But in these cases the only effect would be incorrect
adjustments and this is userspace's responsibility to avoid this.
Fixes: 4eca49d0b621 ("timekeeping: Prepare do_adtimex() for auxiliary clocks")
Signed-off-by: Thomas Weißschuh (Schneider Electric) <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260731-timekeeping-aux-adjtimex-return-v1-1-b7fea4692886@linutronix.de
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cpuset_partition_show() reads cs->prs_err without cpuset_mutex using
READ_ONCE(). The field is documented as not lock protected, but several
updates to live cpusets still use plain stores.
Convert the remaining prs_err stores on live cpusets to WRITE_ONCE().
Fixes: 0c7f293efc87 ("cgroup/cpuset: Add cpuset.cpus.exclusive.effective for v2")
Assisted-by: LLM
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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The timekeeper update path uses a bulk memcpy() to synchronize the
timekeeper structure, which is not guaranteed to be atomic. This allows for
torn reads in ktime_get_real_seconds() on 64-bit systems, where the
sequence counter protection is bypassed for performance.
To prevent reading a torn 64-bit xtime_sec value, enforce atomic-like
access by using WRITE_ONCE() for the critical field before the bulk
memcpy() in timekeeping_update_from_shadow(). Correspondingly, use
READ_ONCE() in ktime_get_real_seconds() to ensure a fresh, consistent load
from memory.
[ tglx: Format changelog and add comment ]
Reported-by: syzbot+72789cd1697965e714ca@syzkaller.appspotmail.com
Signed-off-by: Dennis Moshegov <dennis@xzync.uk>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260724154405.70-1-dennis@xzync.uk
Closes: https://syzkaller.appspot.com/bug?extid=72789cd1697965e714ca
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With the changes that enable preempt count to track IRQ disabling
nesting, we don't have enough bits in 32-bit preempt count
implementation, as a result we move NMI nesting bits out of the 32-bit
preempt count. However on the architectures that can support 64-bit
preempt count implementation, we can keep the NMI nesting bits in the
32-bit preempt count and avoid maintaining NMI nesting bits outside of
the same cache line.
Therefore HAS_SEPARATE_PREEMPT_RESCHED_BITS is introduced to allow
architectures to select this. Note that under this Kconfig, preempt
count is maintained in a 64-bit word however preempt_count() still
remains as an int because all the effective bits still fit in
(previously we mask out NEED_RESCHED bit in preempt_count()). This
should make no functional changes for existing preempt_count() users.
Enable this for x86_64 along with the introduction of the Kconfig.
[boqun: Undo the __preempt_count_{add,sub}() optimization in 32-bit
preempt count since it may introduce {over,under}flow]
Originally-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260804161447.84806-11-boqun@kernel.org
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Currently preempt_count() is always a non-negative int on all archs
(PREEMPT_NEED_RESCHED archs will mask out the MSB when returning
preempt_count()), hence the checking in __cant_migrate() is in fact just
checking whether preempt_count() is 0 or not. In a future change, we are
going to use all the 32 bits of preempt_count(), which would make
negative int values possible from preempt_count(). Therefore convert the
"> 0" comparison into a zero check to prepare for the future change.
No functional changes are intended.
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260804161447.84806-10-boqun@kernel.org
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The preempt_offset is always 0 in all the callsites of __cant_sleep(),
hence remove it. It also allows us to clear up the code a bit by
no longer using a "preempt_count() > .." comparison.
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260804161447.84806-9-boqun@kernel.org
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The semantics of various IRQ disabling guards match what
*_irq_{disable,enable}() provide, i.e. the interrupt disabling is
properly nested, therefore it's OK to switch to use
*_irq_{disable,enable}() primitives.
[boqun: Adjust the user-side changes in do_sched_cfs_*_timer() provided
by Peter and Lyude]
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260804161447.84806-8-boqun@kernel.org
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While making changes to the refcounted interrupt patch series, at some
point on my local branch I broke something and ended up writing some kunit
tests for testing refcounted interrupts as a result. So, let's include
these tests now that we have refcounted interrupts.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260804161447.84806-7-boqun@kernel.org
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Currently the nested interrupt disabling and enabling is represented by
_irqsave() and _irqrestore() APIs, which are relatively unsafe, for
example:
<interrupts are enabled as beginning>
spin_lock_irqsave(l1, flag1);
spin_lock_irqsave(l2, flag2);
spin_unlock_irqrestore(l1, flags1);
<l2 is still held but interrupts are enabled>
// accesses to interrupt-disable protected data will cause races
This is even easier to trigger with guard facilities:
unsigned long flag2;
scoped_guard(spin_lock_irqsave, l1) {
spin_lock_irqsave(l2, flag2);
}
// l2 locked but interrupts are enabled.
spin_unlock_irqrestore(l2, flag2);
(Hand-to-hand locking critical sections are not uncommon for a
fine-grained lock design)
And because of this unsafety, Rust cannot easily wrap the
interrupt-disabling locks in a safe API, which complicates the design.
To resolve this, introduce a new set of interrupt disabling APIs:
* local_interrupt_disable();
* local_interrupt_enable();
They work like local_irq_save() and local_irq_restore() except that 1)
the outermost local_interrupt_disable() call saves the interrupt state
into a per-CPU variable, so that the outermost local_interrupt_enable()
can restore the state, and 2) a per-CPU counter is added to record the
nest level of these calls, so that interrupts are not accidentally
enabled inside the outermost critical section.
Also add the corresponding spin_lock primitives: spin_lock_irq_disable()
and spin_unlock_irq_enable(), as a result, code as follows:
spin_lock_irq_disable(l1);
spin_lock_irq_disable(l2);
spin_unlock_irq_enable(l1);
// Interrupts are still disabled.
spin_unlock_irq_enable(l2);
doesn't have the issue that interrupts are accidentally enabled.
This also makes the wrapper of interrupt-disabling locks on Rust easier
to design.
[boqun: Apply Peter's feedback and fix spell errors reported by Ingo]
[boqun: Address the duplicate spin_acquire() spotted by sashiko]
Co-developed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260804182657.87716-1-boqun@kernel.org
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fprobe_remove_ips() manually duplicates the unregister and filter-removal
logic for both graph and ftrace ops. Simplify it by delegating to the
existing fprobe_graph_remove_ips() and fprobe_ftrace_remove_ips() helpers.
Link: https://lore.kernel.org/all/178528139798.102586.5349128066643420018.stgit@devnote2/
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
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The futex state is used to prevent a waiter from attaching to the lock
owner while the owner runs the futex cleanup in exit() or exec().
Only the state transition from FUTEX_STATE_OK to FUTEX_STATE_EXITING must
be done with the task's pi_lock held, the transition away from
FUTEX_STATE_EXITING has no serialization requirements on the writer side,
but it's completely non obvious why. It's magically protected by
exit_pi_state(), which operates under tsk::pi_lock, as that's the state
which has to be correct when the waiter observes the new state.
OTOH, taking the pi_lock in futex_cleanup_end() is not a performance issue
because at that point the lock should be uncontended in the vast majority
of cases.
Aside of that the handling of FUTEX_STATE_EXITING in attach_to_pi_owner()
and handle_exit_race() is confusing at best.
Protect the store in futex_cleanup_end() with tsk::pi_lock, handle
FUTEX_STATE_EXITING in attach_to_pi_owner() explicitly and document how
this is supposed to work.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Kyle Zeng <kylebot@openai.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
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A private futex key borrows the waiter's mm without taking an mm_users
reference. Nevertheless, attach_to_pi_owner() currently accepts an owner
from a different address space and copies the private key into the owner's
PI state.
When that owner exits, exit_pi_state_list() uses the saved key to find the
hash bucket and acquires a reference to the waiter's private hash. If the
last user of the waiter's mm exits concurrently, futex_hash_free() frees
the hash while the owner still uses its bucket and reference.
Prevent this by validating in attach_to_pi_owner() that, for private
futexes, the owner mm and waiter mm are the same. Perform the check with
the owner's pi_lock held and after validating owner::futex::state to
serialize against a concurrent PI-state exit cleanup.
[ tglx: Amended comment ]
Fixes: 80367ad01d93 ("futex: Add basic infrastructure for local task local hash")
Signed-off-by: Kyle Zeng <kylebot@openai.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Assisted-by: Codex:gpt-5.6-sol
Cc: stable@vger.kernel.org
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Pull tracing fixes from Steven Rostedt:
- Fix use-after-free in eventfs_remove_rec()
The freeing of the eventfs_inode children used list_for_each_entry()
where the child is freed via srcu, but there's still a chance that it
gets freed. It should be using list_for_each_entry_safe().
- Fix eventfs_inode SRCU use of list in freeing
The iterator uses an SRCU protected list walk on the eventfs inodes.
The eventfs inode uses its "list" field in a union with the RCU list
head. When the inode gets added to the SRCU list it immediately
corrupts the list pointer and can cause an issue with the iterator.
Move the RCU list head to be shared with the children list head which
allows the iterator to check the parent inode if is freed before
referencing the child. Have the iterator check the parent "is_freed"
field and break out if it is set. Also add memory barriers to make
sure the ordering is correct.
- Fix various RCU synchronization issues with direct_functions
Updates to direct_functions have some missing RCU protection and
synchronization. Restructure the code a bit to make sure updates to
the direct_functions are protected.
- Remove an unneeded comma from a scope_guard()
There's a spurious comma in a scope_guard(). Remove it.
- Fix race in per CPU buffer swap in the ring buffer
When a per CPU buffer swap happens, it must make sure that it doesn't
occur while a writer is active. Instead it returns an -EBUSY. But
there's a small race window when a writer moves from one sub-buffer
to the next that it resets the "committing" counter. If a swap
happens at that moment, the buffer used for the commit of an event
will not match the buffer the event is actually on. Instead of using
the "committing" counter, use the recursive detection counter that
does not get reset when the writer crosses sub-buffers.
- Fix off-by-one in ftrace_free_mem()
The function ftrace_free_mem() gets an "end_ptr" as a parameter that
is exclusive to the rang to be freed. But its value is used to search
for the records that expects an inclusive value. Subtract one from
the parameter to convert it to an inclusive range.
- Disable resizing of the ring buffer for persistent buffers
Resizing the persistent buffer has undefined behavior. Prevent it
from being resized.
- Disable changing ring buffer subbuf order when resizing is disabled
The ring buffer subbuffer order can not be changed during resizing.
Use that instead of just checking if the buffer is mapped as mapped
buffers also have resizing disabled.
- Initialize subbuf_order of reader pages when they are created
In rb_allocate_cpu_buffer() the bpage->order is not updated to the
current subbuf_order leaving it as zero. This value is used when the
page is freed.
- Fix test_ringbuffer() to test for ERR_PTR before calling
kthread_stop()
The rb_threads[] array is assigned the output of kthread_run_on_cpu()
which could return an ERR_PTR. At the end of the test, all threads in
the array are cleaned up by kthread_stop() passing in the value in
the array if it isn't zero. But if the array contains an ERR_PTR,
kthread_stop() will not be able to handle it properly.
* tag 'trace-v7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Fix crash passing ERR_PTR to kthread_stop()
ring-buffer: Initialise reader page order in rb_allocate_cpu_buffer()
ring-buffer: Prevent subbuf order change when resizing is disabled
ring-buffer: Prevent resizing of persistent ring buffer
ftrace: Fix off-by-one fentry site disable in ftrace_free_mem()
ring-buffer: Use current_context for safe per-CPU buffer swap
ftrace: Drop extra comma in trace_buffered_event_enable
ftrace: Protect direct_functions in update_ftrace_direct_mod
ftrace: Protect direct_functions in update_ftrace_direct_del
ftrace: Protect direct_functions in ftrace_find_rec_direct
eventfs: Use children field for rcu head and add memory barriers
eventfs: Fix use-after-free in eventfs_remove_rec()
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In test_ringbuffer()'s out_free cleanup loop, the check
`!rb_threads[cpu]` only catches NULL entries and misses entries that
hold an ERR_PTR.
rb_threads[] is static, so unassigned slots are NULL. But when
kthread_run_on_cpu() fails for a cpu, it stores ERR_PTR(-ENOMEM) (or
-EINTR) in rb_threads[cpu] before the creation loop jumps to out_free.
That entry is non-NULL, so the old `!ptr` check does not break, and the
cleanup proceeds to call kthread_stop() on the ERR_PTR. kthread_stop()
then dereferences the bogus pointer, crashing the kernel during the
late_initcall self-test.
crash logs:
BUG: kernel NULL pointer dereference, address: 000000000000001c
Oops: 0002 [#1] SMP NOPTI
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 7.2.0-rc6-dirty #7 PREEMPT(lazy)
RIP: 0010:kthread_stop+0x2e/0x220
RBX: fffffffffffffff4
CR2: 000000000000001c
Call Trace:
<TASK>
test_ringbuffer+0x1ec/0x650
do_one_initcall+0x6c/0x2c0
kernel_init_freeable+0x21d/0x420
kernel_init+0x15/0x1c0
ret_from_fork+0x21b/0x320
</TASK>
Kernel panic - not syncing: Fatal exception
Cc: stable@vger.kernel.org
Fixes: 64ed3a049e3e ("ring-buffer: make use of the helper function kthread_run_on_cpu()")
Link: https://patch.msgid.link/20260807154145.2846521-2-sh_def@163.com
Signed-off-by: Hui Su <sh_def@163.com>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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In rb_allocate_cpu_buffer(), bpage->order was omitted, leaving it as 0.
This is an issue for a ring-buffer with subbufs bigger than PAGE_SIZE if
when freed: free_buffer_page() relies on this value. Align the value
with the actual allocation size (buffer::subbuf_order).
Cc: stable@vger.kernel.org
Fixes: f9b94daa542a ("ring-buffer: Set new size of the ring buffer sub page")
Link: https://patch.msgid.link/20260806211306.3704194-4-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Because ring_buffer_subbuf_order_set() frees buffer pages, we can't
allow it when resizing is disabled. A non-consuming reader is at risk of
use-after-free (rb_advance_iter()).
Return -EBUSY on resize_disabled, matching ring_buffer_resize()
behaviour.
Cc: stable@vger.kernel.org
Fixes: f9b94daa542a ("ring-buffer: Set new size of the ring buffer sub page")
Link: https://patch.msgid.link/20260806211306.3704194-3-vdonnefort@google.com
Reported-by: syzbot+e0cc44465d6bae735679@syzkaller.appspotmail.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Dynamically resizing a persistent ring buffer is not possible. Disable
the feature.
Cc: stable@vger.kernel.org
Fixes: be68d63a139b ("ring-buffer: Add ring_buffer_alloc_range()")
Link: https://patch.msgid.link/20260806211306.3704194-2-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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When a module's init text is freed, do_init_module() calls
ftrace_free_mem() with a half-open [start, end) range. However the
ftrace_cmp_recs() comparator treats the upper bound as inclusive, as all
its other users do, passing 'ip + size - 1'. So ftrace_free_mem() can
delete a record sitting exactly at 'end', which is outside the freed
range.
For a kernel without CFI or IBT, the first record of a function is at
the function start, which for the first function in a module is also the
base of its text allocation. As the module allocator packs its regions,
that address is often the 'end' passed by a neighboring module's
do_init_module(), causing the first function's ftrace location to get
disabled, preventing an attempt to livepatch it:
livepatch: failed to find location for function 'pcspkr_probe'
Convert the exclusive end to the inclusive 'end - 1' the comparator
expects, and return early for an empty range to avoid the subtraction
from underflowing when the init text size is zero.
Cc: stable@vger.kernel.org
Fixes: 42c269c88dc1 ("ftrace: Allow for function tracing to record init functions on boot up")
Link: https://patch.msgid.link/1b5ccfa8095bdb1277f84af1c2c2e2205aca03ae.1785992188.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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The ring_buffer_swap_cpu() function currently checks the per-CPU
committing counter to determine if a buffer is actively being written to
before performing the swap. However, there exists a race window where
this check can be bypassed:
ring_buffer_lock_reserve
cpu_buffer = buffer->buffers[cpu]; // cpu_buffer_a
rb_reserve_next_event
rb_start_commit // inc committing
if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
__rb_reserve_next
rb_move_tail
rb_end_commit(cpu_buffer); // dec committing => 0
/* interrupt hits here, successfully swaps! */
local_inc(&cpu_buffer->committing);
ring_buffer_unlock_commit
cpu_buffer = buffer->buffers[cpu]; // cpu_buffer_b
rb_commit
rb_end_commit
RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
// triggers warning
The committing counter can temporarily drop to 0 during a single write
operation (within rb_move_tail), creating a window where swap can
succeed even though the write is still in progress. This leads to
inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().
Replace the committing counter check with current_context checks, which
are set at the entry of ring_buffer_lock_reserve() and remain valid
throughout the entire write operation, providing a reliable indicator of
buffer busy state during swap.
Cc: stable@vger.kernel.org
Fixes: 4239c38fe0b3 ("ring-buffer: Process commits whenever moving to a new page.")
Link: https://patch.msgid.link/20260803005640.2445666-2-wutengda@huaweicloud.com
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Pull futex fix from Ingo Molnar:
- Fix race in futex_pivot_pending() during private hash resize
that can cause stuck tasks (Yao Kai)
* tag 'locking-urgent-2026-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Fix race in futex_pivot_pending() during private hash resize
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Move NMI nesting tracking from the preempt_count bits to a separate
per-CPU counter (nmi_nesting). This is to free up the NMI bits in the
preempt_count, allowing those bits to be repurposed for other uses.
Reduce NMI_BITS from 4 to 1, using it only to detect if we're in an NMI.
The per-CPU counter currently caps nesting at 15.
[boqun: Address Steven Rostedt's comment on the BUG_ON() condition]
[boqun: Use preempt_count_set() in __nmi_exit() to avoid underflow]
Suggested-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260121223933.1568682-3-lyude@redhat.com
Link: https://patch.msgid.link/20260804161447.84806-2-boqun@kernel.org
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Move the event_define_fields() call in event_create_dir() before the
eventfs directory creation. Previously, a failure after directory
creation wouldn't clean up eventfs_inode because the error path didn't
call eventfs_remove_dir(). This eliminates the need to clean up the
eventfs directories if event_define_fields() fails.
Link: https://patch.msgid.link/20260715135231.338535-3-ashelat@redhat.com
Signed-off-by: Anubhav Shelat <ashelat@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Drop the extra comma in "scoped_guard()" to cleanup the code.
Link: https://patch.msgid.link/20260730150411.88667-5-leon.hwang@linux.dev
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Fix accessing the __rcu pointer direct_functions with RCU protection.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-4-leon.hwang@linux.dev
Fixes: e93672f770d7 ("ftrace: Add update_ftrace_direct_mod function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Fix accessing the __rcu pointer direct_functions with RCU protection.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-3-leon.hwang@linux.dev
Fixes: 8d2c1233f371 ("ftrace: Add update_ftrace_direct_del function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Fix accessing the __rcu pointer direct_functions with RCU protection.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-2-leon.hwang@linux.dev
Fixes: d05cb470663a ("ftrace: Fix modification of direct_function hash while in use")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Boot-time tracing currently supports kprobe-events and synthetic-events
under per-event configuration options.
Extend boot-time tracing to support newly added dynamic probe types:
- event probes (eprobe) under the "eprobes" event group
- function probes (fprobe) under the "fprobes" event group
- tracepoint probes (tprobe) under the "tracepoints" or "tprobes"
event group
To support this cleanly, update dyn_event_create() in trace_dynevent.c
so that passing NULL as the type parameter delegates to
create_dyn_event(), allowing generic creation of any registered
dynamic event type from a raw command string.
Update Documentation/trace/boottime-trace.rst accordingly to describe
the new per-event bootconfig options.
Link: https://lore.kernel.org/all/178613905149.259829.18185480460810689421.stgit@devnote2/
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Changes in v3:
- Check return values of strscpy() and snprintf() in trace_boot_add_probe_event()
to prevent silent buffer truncation when constructing probe event strings.
Changes in v2:
- Fix raw command detection logic for eprobes, fprobes, and tprobes
by requiring ':' or isspace() after type prefix.
- Consolidate duplicate loop logic into trace_boot_add_probe_event()
helper function.
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Kmemleak doesn't know about runtime_const stuff and figures we're leaking
__futex_queues. So add this little annotation to tell it all is well.
Fixes: b78b0b658252 ("futex: Use runtime constants for __futex_hash() hot path")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202608071053.6db6276e-lkp@intel.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260807152353.GP687043@noisy.programming.kicks-ass.net
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Reject tracing and freplace attachments to a target program with arena
context arguments. The struct_ops indirect trampoline converts those
arguments before entering the target, so a generic tracing trampoline
would otherwise expose arena offsets using the target BTF pointer type.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-14-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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A struct_ops callback cannot receive an arena pointer directly, so
passing one takes two steps. The pointer arrives as a bare u64 that the
callback casts, and because the two sides address the arena through
different bases it also has to be rebased by hand on the way in.
Add the __arena and __arena__nullable stub argument suffixes to make this
convenient. The callback declares the parameter as an arena pointer,
receives it as a PTR_TO_ARENA register, and dereferences it directly,
while the kernel caller just passes the natural kernel arena address
(kaddr). The trampoline converts the value while saving the arguments
into the BPF ctx, ctx[slot] = (u32)(kaddr - kern_vm_start), so the
program never sees a kernel address and nothing rewrites the ctx after
the fact. The converted value keeps the upper 32 bits clear as the JITs
require of arena pointer registers and behaves like any cast_kern'ed
arena pointer, so cast_user recovers the full user-visible address.
__arena converts unconditionally and the kernel caller must not pass
NULL. __arena__nullable preserves NULL, tested on the full 64-bit kernel
pointer, and surfaces to the verifier as PTR_TO_ARENA (but not as a
PTR_TO_ARENA | PTR_MAYBE_NULL). The reason is that PTR_TO_ARENA in the
program's type state already encompasses NULL-ness, so it is not
meaningful to force a NULL check for the program.
The composite suffix intentionally ends in __nullable. Classify
__arena__nullable before the generic suffix so scalar arena pointees do
not take the generic nullable BTF pointer path.
This patch adds the generic side. prepare_arg_info() records arena and
nullable argument flags in the struct_ops function model, and
bpf_tramp_arena_base() returns the arena base for a single-program
struct_ops indirect trampoline. Only that trampoline converts: its
program's arena is fixed at generation time. Generic trampolines can mix
programs with different arenas and reject arena context arguments
defensively, which is unreachable today as only struct_ops programs
carry them. Architectures that do not implement the conversion are
gated out at verification time with bpf_jit_supports_arena_args().
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-6-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Passing an arena pointer to a kfunc takes two steps today. There is no
arena pointer argument type, so the pointer crosses the boundary as a
bare scalar, and the kfunc then offsets it by the arena base and casts
it before it can touch the memory. Every such kfunc open-codes the same
translation.
Add the __arena and __arena__nullable argument suffixes to make this more
convenient. The kfunc declares the parameter by its real pointer type
and dereferences it directly, with the JIT rebasing the value at the
call site, rN = kern_vm_start + (u32)rN. No bounds check is needed: the
u32 offset stays within the guard-padded arena kernel mapping, and a
fault on an unpopulated page recovers through the per-arena scratch
page. A suffixed argument accepts a PTR_TO_ARENA or scalar register,
matching global subprog arena arguments.
__arena rebases unconditionally, so the kfunc never sees NULL and a
value with zero in the low 32 bits arrives as the arena base.
__arena__nullable preserves NULL for optional arguments by skipping the
rebase when the truncated value, arena offset 0, is zero. Keeping the
plain form NULL-free saves the NULL test on every call.
The double separator makes the annotations composable:
__arena__nullable also ends in __nullable and naturally follows the
common nullable argument path. Plain __arena follows that path too for
verifier type checking because both forms accept a constant zero; the
function-model flag still determines whether the JIT preserves NULL or
rebases it to the arena base.
This patch adds the verifier side: the suffixes are recognized in
check_kfunc_args() and distilled into argument flags in the function
model stored in the kfunc descriptor. JITs retrieve the model while
emitting the call, avoiding per-call state in insn_aux_data.
JITs declare support with bpf_jit_supports_arena_args() and verification
fails with -ENOTSUPP elsewhere.
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-5-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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The kfunc descriptors include argument prototypes generated while calls are
collected. Some argument classifications need program auxiliary state derived
from referenced maps, such as the arena associated with the program.
This avoids a footgun in get_kfunc_arg_type() checks where we do
validation on whether program has prog->aux->arena and it hasn't been
resolved yet.
check_and_resolve_insns() records used maps and populates that state. It must
remain after bpf_check_btf_info(), which applies kernel-side CO-RE relocations,
so that instruction validation and the program tag observe the relocated
instruction stream.
Move only add_kfuncs() after instruction and resource resolution. Subprogram
discovery and validation remain before the full BTF phase because that phase
needs the complete subprogram layout. Add a short comment describing the
resource resolution phase at the call site.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-4-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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add_subprog_and_kfunc() combines two operations with different ordering
requirements. Subprogram discovery must precede validation of func_info and
line_info, while kfunc descriptors are only needed by the verifier after its
initial program setup is complete.
Split the helper into add_subprogs() and add_kfuncs() so each operation can be
placed according to its actual dependencies. Keep both calls adjacent and in
their existing phase for now, and add short comments describing their roles.
No functional change is intended for valid programs.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-3-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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BTF processing is split around subprogram discovery. The first phase gets
program BTF and imports func_info because a BTF-tagged exception callback
may not be referenced by any instruction. Subprogram discovery needs this
metadata to find it.
The later phase validates func_info and line_info against the complete
subprogram table and applies CO-RE relocations. This split breaks a real
dependency cycle rather than merely running the same checks early.
Rename bpf_check_btf_info_early() and check_btf_func_early() to preparation
names that reflect this role. Add short call-site comments to make the two
phases and their responsibilities clear.
No functional change is intended.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-2-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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After the previous commit bpf_is_reg64() is only used in a context
where destination register's property is queried, and only for
instructions for which insn_def_regno() >= 0. Hence, simplify the
function by:
- removing unused parameters;
- removing code paths considering BPF_JMP{,32} instructions;
- streamlining the condition expressions.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-6-b6c270013c77@gmail.com
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As reported in the thread [1], the verifier's 32-bit operations zero
extension logic is broken. This logic is responsible for correct
semantics of 32-bit operations on s390 architecture.
According to BPF semantics, operation `w1 += 1` is supposed to zero
extend the upper half of the register `r1`. On s390 the JIT relies on
the verifier emitting explicit zero extension before such operations.
The verifier attempts to minimize the amount of zero extensions
inserted by tracking whether upper halves of the 64-bit registers are
ever used. Previously such tracking worked as follows:
- bpf_reg_state->subreg_def field was set by do_check_insn()
for each operation defining lower but not the upper halves
of the register.
- Whenever an operation reading the whole register was verified,
the verifier checked register's subreg_def and set
bpf_insn_aux_data->zext_dst flag as true via a call to
mark_insn_zext() function.
- After the verification was complete, a special pass
bpf_opt_subreg_zext_lo32_rnd_hi32() extended 32-bit operations
with bpf_insn_aux_data->zext_dst set as true by adding
explicit zero extension.
Note that the logic above relies on bpf_reg_state->subreg_def,
which is a property of a current verifier state.
Before the commit [2] two additional steps happened:
- The verifier tracked upper and lower register halves' liveness as
flags REG_LIVE_READ{32,64} in bpf_reg_state->live.
- The function propagate_liveness() called mark_insn_zext()
in order to transfer the knowledge about which registers have
their upper halves alive (and thus might require zero extension).
The commit [2] removed the two steps described above,
hence making possible a situation like below:
- The register's upper half is set and is used on some verification
path P1 and the register happens not to be marked as precise.
- The checkpoint C is created while processing some instruction
between register initialization and usage.
- On some other verification path P2 the register's upper half is not
initialized and that path ends hitting the checkpoint C.
- In such a case the register's initialization on path P2 would lack
zext_dst mark, making it possible for the program to inject
an arbitrary value in the register's upper half.
This commit replaces subreg_def based logic with computing zext_dst
statically, as a part of the bpf_compute_live_registers() analysis:
- The analysis now tracks usage of upper and lower halves of the
registers separately.
- If some instruction defines a 32-bit subregister, but not the whole
register, *and* the upper half of the register is alive after that
instruction, the instruction is marked as zext_dst.
There is one notable drop in precision: whenever a BPF subprogram is
called, all 64 bits of parameter registers are presumed to be used.
The assumption is that such a drop in precision would not inflict
a noticeable performance penalty.
[1] https://lore.kernel.org/bpf/CAGKGUv=sOuqQtA1Ub-5JXfA4FPosJFYKAQE4B79cK+P1erxqtg@mail.gmail.com/
[2] commit 107e16979905 ("bpf: disable and remove registers chain based liveness")
Fixes: 107e16979905 ("bpf: disable and remove registers chain based liveness")
Reported-by: Min-gyu Kim <gimm78064@gmail.com>
Reported-by: STAR Labs SG <info@starlabs.sg>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/CAGKGUv=sOuqQtA1Ub-5JXfA4FPosJFYKAQE4B79cK+P1erxqtg@mail.gmail.com/
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-5-b6c270013c77@gmail.com
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Extend compute_live_registers() to track upper and lower register
halves' liveness separately. This is mostly straightforward:
- use/def masks are extended to track 2 bits per register;
- compute_insn_live_regs() is updated to properly track these
2 bits according to the instruction semantics.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-4-b6c270013c77@gmail.com
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The following patches are going to remove bpf_is_reg64() users from
everywhere except fixups.c, and also make it dependent on functions
local to fixups.c. Move the function before hand to simplify the
review. Non functional change.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-3-b6c270013c77@gmail.com
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bpf_do_misc_fixups() converts the following address space cast
instructions to 32-bit moves:
- cast from address space 1 (user) to address space 0 (kernel)
- cast from address space 0 (kernel) to address space 1 (user)
iff associated arena map has a BPF_F_NO_USER_CONV flag.
Extract a predicate detecting such instructions for use in the
following patches.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-2-b6c270013c77@gmail.com
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At the moment there are more callsites that want bpf_verbose_insn() to
not print a newline after the instruction, than callsites that want a
newline. Drop '\n' from disasm.c. Non-functional change.
The changes in bpftool are verified by writing a bpf program using a
variety of instructions and comparing `prog dump xlated` output in the
following modes: plain, opcodes, visual, visual opcodes. The output
before and after the changes is identical.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-1-b6c270013c77@gmail.com
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stack_map_get_build_id_offset() introduced a per-CPU irq_work to defer
mmap_read_unlock() from NMI context, and bpf_find_vma() later reused the
same mmap_unlock_work. Both callers only check whether the work is busy
before taking mmap_lock, so a nested caller can reuse the slot before the
first caller queues it. Two read locks may then be acquired while only one
deferred unlock runs, leaking a read lock and blocking exit_mmap().
Reserve the per-CPU slot before mmap_read_trylock(). Use the same wrapper
in stackmap and bpf_find_vma() so both callers release the reservation on
trylock failure. Keep rejecting the slot while the irq_work remains busy.
Release it after the irq_work callback unlocks the mm.
Fixes: eac9153f2b58 ("bpf/stackmap: Fix deadlock with rq_lock in bpf_get_stack()")
Reported-by: syzbot+cdd6c0925e12b0af60cc@syzkaller.appspotmail.com
Reported-by: sashiko-bot@kernel.org
Signed-off-by: Sanghyun Park <sanghyun.park.cnu@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Closes: https://syzkaller.appspot.com/bug?extid=cdd6c0925e12b0af60cc
Closes: https://lore.kernel.org/r/20260630033745.B80201F000E9@smtp.kernel.org
Link: https://lore.kernel.org/bpf/20260805031425.2157475-2-sanghyun.park.cnu@gmail.com
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In mmio_print_mark(), a raw C cast (struct print_entry *)entry is used to
obtain the print_entry pointer.
Use the standard trace_assign_type() macro instead, matching the usage in
mmio_print_rw() and mmio_print_map().
Link: https://patch.msgid.link/178524301013.56416.9116249028160618790.stgit@devnote2
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Syzkaller reported a storage null-ptr-deref issue after replacing prog.
This occurs in the following scenario:
1. prog A, an empty prog, is attached to a cgrp.
2. prog B uses BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE and calls the
bpf_get_local_storage helper.
3. link_update is called to replace prog A with prog B.
The reason is that __cgroup_bpf_replace fails to alloc and assign the
required cgrp storage for the incoming replacement prog. Consequently,
the new prog inherits an uninit storage, leading to null-ptr-deref panic
when kick the new prog.
Fix this by rejecting a link update if new_prog's cgroup storage is
incompatible with link->prog.
Fixes: 0c991ebc8c69 ("bpf: Implement bpf_prog replacement for an active bpf_cgroup_link")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/bpf/20260728132336.2857800-1-pulehui@huaweicloud.com [0]
Link: https://lore.kernel.org/bpf/f87b53c0-8f00-45a6-82db-8242fa9b143f@huaweicloud.com [1]
Link: https://lore.kernel.org/bpf/20260807104403.1013064-1-pulehui@huaweicloud.com
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Breno Leitao
Thomas Weißschuh (Schneider Electric)
Guopeng Zhang
Dennis Moshegov
Boqun Feng
Lyude Paul
Masami Hiramatsu (Google)
Thomas Gleixner
Kyle Zeng
Linus Torvalds
Hui Su
Vincent Donnefort
Josh Poimboeuf
Tengda Wu
Joel Fernandes
Anubhav Shelat
Leon Hwang
Peter Zijlstra
Kumar Kartikeya Dwivedi
Tejun Heo
Eduard Zingerman
Sanghyun Park
Pu Lehui