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Implement session cookie for fsession. The session cookies will be stored
in the stack, and the layout of the stack will look like this:
return value -> 8 bytes
argN -> 8 bytes
...
arg1 -> 8 bytes
nr_args -> 8 bytes
ip (optional) -> 8 bytes
cookie2 -> 8 bytes
cookie1 -> 8 bytes
The offset of the cookie for the current bpf program, which is in 8-byte
units, is stored in the
"(((u64 *)ctx)[-1] >> BPF_TRAMP_COOKIE_INDEX_SHIFT) & 0xFF". Therefore, we
can get the session cookie with ((u64 *)ctx)[-offset].
Implement and inline the bpf_session_cookie() for the fsession in the
verifier.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20260124062008.8657-6-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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If fsession exists, we will use the bit (1 << BPF_TRAMP_IS_RETURN_SHIFT)
in ((u64 *)ctx)[-1] to store the "is_return" flag.
The logic of bpf_session_is_return() for fsession is implemented in the
verifier by inline following code:
bool bpf_session_is_return(void *ctx)
{
return (((u64 *)ctx)[-1] >> BPF_TRAMP_IS_RETURN_SHIFT) & 1;
}
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Co-developed-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260124062008.8657-5-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Add the function argument of "void *ctx" to bpf_session_cookie() and
bpf_session_is_return(), which is a preparation of the next patch.
The two kfunc is seldom used now, so it will not introduce much effect
to change their function prototype.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20260124062008.8657-4-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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For now, ((u64 *)ctx)[-1] is used to store the nr_args in the trampoline.
However, 1 byte is enough to store such information. Therefore, we use
only the least significant byte of ((u64 *)ctx)[-1] to store the nr_args,
and reserve the rest for other usages.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20260124062008.8657-3-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The fsession is something that similar to kprobe session. It allow to
attach a single BPF program to both the entry and the exit of the target
functions.
Introduce the struct bpf_fsession_link, which allows to add the link to
both the fentry and fexit progs_hlist of the trampoline.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Co-developed-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260124062008.8657-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix a crash with passing a stacktrace between synthetic events
A synthetic event is an event that combines two events into a single
event that can display fields from both events as well as the time
delta that took place between the events. It can also pass a
stacktrace from the first event so that it can be displayed by the
synthetic event (this is useful to get a stacktrace of a task
scheduling out when blocked and recording the time it was blocked
for).
A synthetic event can also connect an existing synthetic event to
another event. An issue was found that if the first synthetic event
had a stacktrace as one of its fields, and that stacktrace field was
passed to the new synthetic event to be displayed, it would crash the
kernel. This was due to the stacktrace not being saved as a
stacktrace but was still marked as one. When the stacktrace was read,
it would try to read an array but instead read the integer metadata
of the stacktrace and dereferenced a bad value.
Fix this by saving the stacktrace field as a stacktrace.
- Fix possible overflow in cmp_mod_entry() compare function
A binary search is used to find a module address and if the addresses
are greater than 2GB apart it could lead to truncation and cause a
bad search result. Use normal compares instead of a subtraction
between addresses to calculate the compare value.
- Fix output of entry arguments in function graph tracer
Depending on the configurations enabled, the entry can be two
different types that hold the argument array. The macro
FGRAPH_ENTRY_ARGS() is used to find the correct arguments from the
given type. One location was missed and still referenced the
arguments directly via entry->args and could produce the wrong value
depending on how the kernel was configured.
- Fix memory leak in scripts/tracepoint-update build tool
If the array fails to allocate, the memory for the values needs to be
freed and was not. Free the allocated values if the array failed to
allocate.
* tag 'trace-v6.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
scripts/tracepoint-update: Fix memory leak in add_string() on failure
function_graph: Fix args pointer mismatch in print_graph_retval()
tracing: Avoid possible signed 64-bit truncation
tracing: Fix crash on synthetic stacktrace field usage
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar:
- Fix auxiliary timekeeper update & locking bug
- Reduce the sensitivity of the clocksource watchdog,
to fix false positive measurements that marked the
TSC clocksource unstable
* tag 'timers-urgent-2026-01-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource: Reduce watchdog readout delay limit to prevent false positives
timekeeping: Adjust the leap state for the correct auxiliary timekeeper
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
- Fix PELT clock synchronization bug when entering idle
- Disable the NEXT_BUDDY feature, as during extensive testing
Mel found that the negatives outweigh the positives
- Make wakeup preemption less aggressive, which resulted in
an unreasonable increase in preemption frequency
* tag 'sched-urgent-2026-01-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Revert force wakeup preemption
sched/fair: Disable scheduler feature NEXT_BUDDY
sched/fair: Fix pelt clock sync when entering idle
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events fixes from Ingo Molnar:
- Fix mmap_count warning & bug when creating a group member event
with the PERF_FLAG_FD_OUTPUT flag
- Disable the sample period == 1 branch events BTS optimization
on guests, because BTS is not virtualized
* tag 'perf-urgent-2026-01-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Do not enable BTS for guests
perf: Fix refcount warning on event->mmap_count increment
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Merge in patches to support several patch series such as Soft Reserve
handling, type2 accelerator enabling, and LSA 2.1 labeling support.
Mainly addition of cxl_memdev_attach() to allow the memdev probe
to make a decision of proceed/fail depending success of CXL topology
enumeration.
dax/hmem, e820, resource: Defer Soft Reserved insertion until hmem is ready
cxl/mem: Introduce cxl_memdev_attach for CXL-dependent operation
cxl/mem: Drop @host argument to devm_cxl_add_memdev()
cxl/mem: Convert devm_cxl_add_memdev() to scope-based-cleanup
cxl/port: Arrange for always synchronous endpoint attach
cxl/mem: Arrange for always-synchronous memdev attach
cxl/mem: Fix devm_cxl_memdev_edac_release() confusion
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* rcu-nocb.20260123a:
rcu/nocb: Extract nocb_defer_wakeup_cancel() helper
rcu/nocb: Remove dead callback overload handling
rcu/nocb: Remove unnecessary WakeOvfIsDeferred wake path
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The pattern of checking nocb_defer_wakeup and deleting the timer is
duplicated in __wake_nocb_gp() and nocb_gp_wait(). Extract this into a
common helper function nocb_defer_wakeup_cancel().
This removes code duplication and makes it easier to maintain.
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
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During callback overload (exceeding qhimark), the NOCB code attempts
opportunistic advancement via rcu_advance_cbs_nowake(). Analysis shows
this code path is practically unreachable and serves no useful purpose.
Testing with 300,000 callback floods showed:
- 30 overload conditions triggered
- 0 advancements actually occurred
While a theoretical window exists where this code could execute (e.g.,
vCPU preemption between gp_seq update and rcu_nocb_gp_cleanup()), even
if it did, the advancement would be redundant. The rcuog kthread must
still run to wake the rcuoc callback thread - we would just be
duplicating work that rcuog will perform when it finally gets to run.
Since this path provides no meaningful benefit and extensive testing
confirms it is never useful, remove it entirely.
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
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The WakeOvfIsDeferred code path in __call_rcu_nocb_wake() attempts to
wake rcuog when the callback count exceeds qhimark and callbacks aren't
done with their GP (newly queued or awaiting GP). However, a lot of
testing proves this wake is always redundant or useless.
In the flooding case, rcuog is always waiting for a GP to finish. So
waking up the rcuog thread is pointless. The timer wakeup adds overhead,
rcuog simply wakes up and goes back to sleep achieving nothing.
This path also adds a full memory barrier, and additional timer expiry
modifications unnecessarily.
The root cause is that WakeOvfIsDeferred fires when
!rcu_segcblist_ready_cbs() (GP not complete), but waking rcuog cannot
accelerate GP completion.
This commit therefore removes this path.
Tested with rcutorture scenarios: TREE01, TREE05, TREE08 (all NOCB
configurations) - all pass. Also stress tested using a kernel module
that floods call_rcu() to trigger the overload conditions and made the
observations confirming the findings.
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
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When funcgraph-args and funcgraph-retaddr are both enabled, many kernel
functions display invalid parameters in trace logs.
The issue occurs because print_graph_retval() passes a mismatched args
pointer to print_function_args(). Fix this by retrieving the correct
args pointer using the FGRAPH_ENTRY_ARGS() macro.
Link: https://patch.msgid.link/20260112021601.1300479-1-dolinux.peng@gmail.com
Fixes: f83ac7544fbf ("function_graph: Enable funcgraph-args and funcgraph-retaddr to work simultaneously")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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64-bit truncation to 32-bit can result in the sign of the truncated
value changing. The cmp_mod_entry is used in bsearch and so the
truncation could result in an invalid search order. This would only
happen were the addresses more than 2GB apart and so unlikely, but
let's fix the potentially broken compare anyway.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260108002625.333331-1-irogers@google.com
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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When creating a synthetic event based on an existing synthetic event that
had a stacktrace field and the new synthetic event used that field a
kernel crash occurred:
~# cd /sys/kernel/tracing
~# echo 's:stack unsigned long stack[];' > dynamic_events
~# echo 'hist:keys=prev_pid:s0=common_stacktrace if prev_state & 3' >> events/sched/sched_switch/trigger
~# echo 'hist:keys=next_pid:s1=$s0:onmatch(sched.sched_switch).trace(stack,$s1)' >> events/sched/sched_switch/trigger
The above creates a synthetic event that takes a stacktrace when a task
schedules out in a non-running state and passes that stacktrace to the
sched_switch event when that task schedules back in. It triggers the
"stack" synthetic event that has a stacktrace as its field (called "stack").
~# echo 's:syscall_stack s64 id; unsigned long stack[];' >> dynamic_events
~# echo 'hist:keys=common_pid:s2=stack' >> events/synthetic/stack/trigger
~# echo 'hist:keys=common_pid:s3=$s2,i0=id:onmatch(synthetic.stack).trace(syscall_stack,$i0,$s3)' >> events/raw_syscalls/sys_exit/trigger
The above makes another synthetic event called "syscall_stack" that
attaches the first synthetic event (stack) to the sys_exit trace event and
records the stacktrace from the stack event with the id of the system call
that is exiting.
When enabling this event (or using it in a historgram):
~# echo 1 > events/synthetic/syscall_stack/enable
Produces a kernel crash!
BUG: unable to handle page fault for address: 0000000000400010
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 6 UID: 0 PID: 1257 Comm: bash Not tainted 6.16.3+deb14-amd64 #1 PREEMPT(lazy) Debian 6.16.3-1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
RIP: 0010:trace_event_raw_event_synth+0x90/0x380
Code: c5 00 00 00 00 85 d2 0f 84 e1 00 00 00 31 db eb 34 0f 1f 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 <49> 8b 04 24 48 83 c3 01 8d 0c c5 08 00 00 00 01 cd 41 3b 5d 40 0f
RSP: 0018:ffffd2670388f958 EFLAGS: 00010202
RAX: ffff8ba1065cc100 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: fffff266ffda7b90 RDI: ffffd2670388f9b0
RBP: 0000000000000010 R08: ffff8ba104e76000 R09: ffffd2670388fa50
R10: ffff8ba102dd42e0 R11: ffffffff9a908970 R12: 0000000000400010
R13: ffff8ba10a246400 R14: ffff8ba10a710220 R15: fffff266ffda7b90
FS: 00007fa3bc63f740(0000) GS:ffff8ba2e0f48000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000400010 CR3: 0000000107f9e003 CR4: 0000000000172ef0
Call Trace:
<TASK>
? __tracing_map_insert+0x208/0x3a0
action_trace+0x67/0x70
event_hist_trigger+0x633/0x6d0
event_triggers_call+0x82/0x130
trace_event_buffer_commit+0x19d/0x250
trace_event_raw_event_sys_exit+0x62/0xb0
syscall_exit_work+0x9d/0x140
do_syscall_64+0x20a/0x2f0
? trace_event_raw_event_sched_switch+0x12b/0x170
? save_fpregs_to_fpstate+0x3e/0x90
? _raw_spin_unlock+0xe/0x30
? finish_task_switch.isra.0+0x97/0x2c0
? __rseq_handle_notify_resume+0xad/0x4c0
? __schedule+0x4b8/0xd00
? restore_fpregs_from_fpstate+0x3c/0x90
? switch_fpu_return+0x5b/0xe0
? do_syscall_64+0x1ef/0x2f0
? do_fault+0x2e9/0x540
? __handle_mm_fault+0x7d1/0xf70
? count_memcg_events+0x167/0x1d0
? handle_mm_fault+0x1d7/0x2e0
? do_user_addr_fault+0x2c3/0x7f0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The reason is that the stacktrace field is not labeled as such, and is
treated as a normal field and not as a dynamic event that it is.
In trace_event_raw_event_synth() the event is field is still treated as a
dynamic array, but the retrieval of the data is considered a normal field,
and the reference is just the meta data:
// Meta data is retrieved instead of a dynamic array
str_val = (char *)(long)var_ref_vals[val_idx];
// Then when it tries to process it:
len = *((unsigned long *)str_val) + 1;
It triggers a kernel page fault.
To fix this, first when defining the fields of the first synthetic event,
set the filter type to FILTER_STACKTRACE. This is used later by the second
synthetic event to know that this field is a stacktrace. When creating
the field of the new synthetic event, have it use this FILTER_STACKTRACE
to know to create a stacktrace field to copy the stacktrace into.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Link: https://patch.msgid.link/20260122194824.6905a38e@gandalf.local.home
Fixes: 00cf3d672a9d ("tracing: Allow synthetic events to pass around stacktraces")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The TAS fallback can be invoked directly when queued spin locks are
disabled, and through the slow path when paravirt is enabled for queued
spin locks. In the latter case, the res_spin_lock macro will attempt the
fast path and already hold the entry when entering the slow path. This
will lead to creation of extraneous entries that are not released, which
may cause false positives for deadlock detection.
Fix this by always preceding invocation of the TAS fallback in every
case with the grabbing of the held lock entry, and add a comment to make
note of this.
Fixes: c9102a68c070 ("rqspinlock: Add a test-and-set fallback")
Reported-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/r/20260122115911.3668985-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This agressively bypasses run_to_parity and slice protection with the
assumpiton that this is what waker wants but there is no garantee that
the wakee will be the next to run. It is a better choice to use
yield_to_task or WF_SYNC in such case.
This increases the number of resched and preemption because a task becomes
quickly "ineligible" when it runs; We update the task vruntime periodically
and before the task exhausted its slice or at least quantum.
Example:
2 tasks A and B wake up simultaneously with lag = 0. Both are
eligible. Task A runs 1st and wakes up task C. Scheduler updates task
A's vruntime which becomes greater than average runtime as all others
have a lag == 0 and didn't run yet. Now task A is ineligible because
it received more runtime than the other task but it has not yet
exhausted its slice nor a min quantum. We force preemption, disable
protection but Task B will run 1st not task C.
Sidenote, DELAY_ZERO increases this effect by clearing positive lag at
wake up.
Fixes: e837456fdca8 ("sched/fair: Reimplement NEXT_BUDDY to align with EEVDF goals")
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260123102858.52428-1-vincent.guittot@linaro.org
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NEXT_BUDDY was disabled with the introduction of EEVDF and enabled again
after NEXT_BUDDY was rewritten for EEVDF by commit e837456fdca8 ("sched/fair:
Reimplement NEXT_BUDDY to align with EEVDF goals"). It was not expected
that this would be a universal win without a crystal ball instruction
but the reported regressions are a concern [1][2] even if gains were
also reported. Specifically;
o mysql with client/server running on different servers regresses
o specjbb reports lower peak metrics
o daytrader regresses
The mysql is realistic and a concern. It needs to be confirmed if
specjbb is simply shifting the point where peak performance is measured
but still a concern. daytrader is considered to be representative of a
real workload.
Access to test machines is currently problematic for verifying any fix to
this problem. Disable NEXT_BUDDY for now by default until the root causes
are addressed.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
Link: https://lore.kernel.org/lkml/4b96909a-f1ac-49eb-b814-97b8adda6229@arm.com [1]
Link: https://lore.kernel.org/lkml/ec3ea66f-3a0d-4b5a-ab36-ce778f159b5b@linux.ibm.com [2]
Link: https://patch.msgid.link/fyqsk63pkoxpeaclyqsm5nwtz3dyejplr7rg6p74xwemfzdzuu@7m7xhs5aqpqw
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These structs are never modified.
To prevent malicious or accidental modifications due to bugs,
mark them as const.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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When the kallsyms relative base was introduced, per-CPU variable
references on x86_64 SMP were implemented as offsets into the respective
per-CPU region, rather than offsets relative to the location of the
variable's template in the kernel image, which is how other
architectures implement it.
This required kallsyms to reason about the difference between the two,
and the sign of the value in the kallsyms_offsets[] array was used to
distinguish them. This meant that negative offsets were not permitted
for ordinary variables, and so it was crucial that the relative base was
chosen such that all offsets were positive numbers.
This is no longer needed: instead, the offsets can simply be encoded as
values in the range -/+ 2 GiB, which is precisely what PC32 relocations
provide on most architectures. So it is possible to simplify the logic,
and just use _text as the anchor directly, and let the linker calculate
the final value based on the location of the entry itself.
Some architectures (nios2, extensa) do not support place-relative
relocations at all, but these are all 32-bit and non-relocatable, and so
there is no need for place-relative relocations in the first place, and
the actual symbol values can just be stored directly.
This makes all entries in the kallsyms_offsets[] array visible as
place-relative references in the ELF metadata, which will be important
when implementing ELF-based fg-kaslr.
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://patch.msgid.link/20260116093359.2442297-6-ardb+git@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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1) The commit:
2b8272ff4a70 ("cpu/hotplug: Prevent self deadlock on CPU hot-unplug")
was added to fix an issue where the hotplug control task (BP) was
throttled between CPUHP_AP_IDLE_DEAD and CPUHP_HRTIMERS_PREPARE waiting
in the hrtimer blindspot for the bandwidth callback queued in the dead
CPU.
2) Later on, the commit:
38685e2a0476 ("cpu/hotplug: Don't offline the last non-isolated CPU")
plugged on the target selection for the workqueue offloaded CPU down
process to prevent from destroying the last CPU domain.
3) Finally:
5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
removed entirely the conditions for the race exposed and partially fixed
in 1). The offloading of the CPU down process to a workqueue on another
CPU then becomes unnecessary. But the last CPU belonging to scheduler
domains must still remain online.
Therefore revert the now obsolete commit
2b8272ff4a70b866106ae13c36be7ecbef5d5da2 and move the housekeeping check
under the cpu_hotplug_lock write held. Since HK_TYPE_DOMAIN will include
both isolcpus and cpuset isolated partition, the hotplug lock will
synchronize against concurrent cpuset partition updates.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
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Currently, rq->idle_stamp is only used to calculate avg_idle during
wakeups. This means other paths that move a task to an idle CPU such as
fork/clone, execve, or migrations, do not end the CPU's idle status in
the scheduler's eyes, leading to an inaccurate avg_idle.
This patch introduces update_rq_avg_idle() to provide a more accurate
measurement of CPU idle duration. By invoking this helper in
put_prev_task_idle(), we ensure avg_idle is updated whenever a CPU
stops being idle, regardless of how the new task arrived.
Testing on an 80-core Ampere Altra (ARMv8) with 6.19-rc5 baseline:
- Hackbench : +7.2% performance gain at 16 threads.
- Schbench: Reduced p99.9 tail latencies at high concurrency.
Signed-off-by: Shubhang Kaushik <shubhang@os.amperecomputing.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: Shubhang Kaushik <shubhang@os.amperecomputing.com>
Link: https://patch.msgid.link/20260121-v8-patch-series-v8-1-b7f1cbee5055@os.amperecomputing.com
|
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It turns out that __run_hrtimer() will trace like:
<idle>-0 [032] d.h2. 20705.474563: hrtimer_cancel: hrtimer=0xff2db8f77f8226e8
<idle>-0 [032] d.h1. 20705.474563: hrtimer_expire_entry: hrtimer=0xff2db8f77f8226e8 now=20699452001850 function=tick_nohz_handler/0x0
Which is a bit nonsensical, the timer doesn't get canceled on
expiration. The cause is the use of the incorrect debug helper.
Fixes: c6a2a1770245 ("hrtimer: Add tracepoint for hrtimers")
Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260121143208.219595606@infradead.org
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Change the minimum slice extension to 5 usec.
Since slice_test selftest reaches a staggering ~350 nsec extension:
Task: slice_test Mean: 350.266 ns
Latency (us) | Count
------------------------------
EXPIRED | 238
0 us | 143189
1 us | 167
2 us | 26
3 us | 11
4 us | 28
5 us | 31
6 us | 22
7 us | 23
8 us | 32
9 us | 16
10 us | 35
Lower the minimal (and default) value to 5 usecs -- which is still massive.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260121143208.073200729@infradead.org
|
|
Move changing the slice ext duration to debugfs, a sliglty less permanent
interface.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260121143207.923520192@infradead.org
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Since glibc cares about the number of syscalls required to initialize a new
thread, allow initializing rseq with slice extension on. This avoids having to
do another prctl().
Requested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260121143207.814193010@infradead.org
|
|
Wire the grant decision function up in exit_to_user_mode_loop()
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155709.258157362@linutronix.de
|
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If a time slice extension is granted and the reschedule delayed, the kernel
has to ensure that user space cannot abuse the extension and exceed the
maximum granted time.
It was suggested to implement this via the existing hrtick() timer in the
scheduler, but that turned out to be problematic for several reasons:
1) It creates a dependency on CONFIG_SCHED_HRTICK, which can be disabled
independently of CONFIG_HIGHRES_TIMERS
2) HRTICK usage in the scheduler can be runtime disabled or is only used
for certain aspects of scheduling.
3) The function is calling into the scheduler code and that might have
unexpected consequences when this is invoked due to a time slice
enforcement expiry. Especially when the task managed to clear the
grant via sched_yield(0).
It would be possible to address #2 and #3 by storing state in the
scheduler, but that is extra complexity and fragility for no value.
Implement a dedicated per CPU hrtimer instead, which is solely used for the
purpose of time slice enforcement.
The timer is armed when an extension was granted right before actually
returning to user mode in rseq_exit_to_user_mode_restart().
It is disarmed, when the task relinquishes the CPU. This is expensive as
the timer is probably the first expiring timer on the CPU, which means it
has to reprogram the hardware. But that's less expensive than going through
a full hrtimer interrupt cycle for nothing.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251215155709.068329497@linutronix.de
|
|
The kernel sets SYSCALL_WORK_RSEQ_SLICE when it grants a time slice
extension. This allows to handle the rseq_slice_yield() syscall, which is
used by user space to relinquish the CPU after finishing the critical
section for which it requested an extension.
In case the kernel state is still GRANTED, the kernel resets both kernel
and user space state with a set of sanity checks. If the kernel state is
already cleared, then this raced against the timer or some other interrupt
and just clears the work bit.
Doing it in syscall entry work allows to catch misbehaving user space,
which issues an arbitrary syscall, i.e. not rseq_slice_yield(), from the
critical section. Contrary to the initial strict requirement to use
rseq_slice_yield() arbitrary syscalls are not considered a violation of the
ABI contract anymore to allow onion architecture applications, which cannot
control the code inside a critical section, to utilize this as well.
If the code detects inconsistent user space that result in a SIGSEGV for
the application.
If the grant was still active and the task was not preempted yet, the work
code reschedules immediately before continuing through the syscall.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155709.005777059@linutronix.de
|
|
Provide a new syscall which has the only purpose to yield the CPU after the
kernel granted a time slice extension.
sched_yield() is not suitable for that because it unconditionally
schedules, but the end of the time slice extension is not required to
schedule when the task was already preempted. This also allows to have a
strict check for termination to catch user space invoking random syscalls
including sched_yield() from a time slice extension region.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patch.msgid.link/20251215155708.929634896@linutronix.de
|
|
Implement a prctl() so that tasks can enable the time slice extension
mechanism. This fails, when time slice extensions are disabled at compile
time or on the kernel command line and when no rseq pointer is registered
in the kernel.
That allows to implement a single trivial check in the exit to user mode
hotpath, to decide whether the whole mechanism needs to be invoked.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155708.858717691@linutronix.de
|
|
Extend the quick statistics with time slice specific fields.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155708.795202254@linutronix.de
|
|
Guard the time slice extension functionality with a static key, which can
be disabled on the kernel command line.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155708.733429292@linutronix.de
|
|
Aside of a Kconfig knob add the following items:
- Two flag bits for the rseq user space ABI, which allow user space to
query the availability and enablement without a syscall.
- A new member to the user space ABI struct rseq, which is going to be
used to communicate request and grant between kernel and user space.
- A rseq state struct to hold the kernel state of this
- Documentation of the new mechanism
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155708.669472597@linutronix.de
|
|
Using kstrtouint_from_user() instead of copy_from_user() + kstrtouint()
makes the code simpler and less error-prone.
Suggested-by: Yury Norov <ynorov@nvidia.com>
Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Yury Norov <ynorov@nvidia.com>
Link: https://patch.msgid.link/20260117145615.53455-2-fushuai.wang@linux.dev
|
|
bpf_strncasecmp() function performs same like bpf_strcasecmp() except
limiting the comparison to a specific length.
Signed-off-by: Yuzuki Ishiyama <ishiyama@hpc.is.uec.ac.jp>
Acked-by: Viktor Malik <vmalik@redhat.com>
Acked-by: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
Link: https://lore.kernel.org/r/20260121033328.1850010-2-ishiyama@hpc.is.uec.ac.jp
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
For now, bpf_get_func_arg() and bpf_get_func_arg_cnt() is not supported by
the BPF_TRACE_RAW_TP, which is not convenient to get the argument of the
tracepoint, especially for the case that the position of the arguments in
a tracepoint can change.
The target tracepoint BTF type id is specified during loading time,
therefore we can get the function argument count from the function
prototype instead of the stack.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20260121044348.113201-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Samuel and Alex reported regressions of the util_avg of RT rq with
commit 17e3e88ed0b6 ("sched/fair: Fix pelt lost idle time detection").
It happens that fair is updating and syncing the pelt clock with task one
when pick_next_task_fair() fails to pick a task but before the prev
scheduling class got a chance to update its pelt signals.
Move update_idle_rq_clock_pelt() in set_next_task_idle() which is called
after prev class has been called.
Fixes: 17e3e88ed0b6 ("sched/fair: Fix pelt lost idle time detection")
Closes: https://lore.kernel.org/all/CAG2KctpO6VKS6GN4QWDji0t92_gNBJ7HjjXrE+6H+RwRXt=iLg@mail.gmail.com/
Closes: https://lore.kernel.org/all/8cf19bf0e0054dcfed70e9935029201694f1bb5a.camel@mediatek.com/
Reported-by: Samuel Wu <wusamuel@google.com>
Reported-by: Alex Hoh <Alex.Hoh@mediatek.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Samuel Wu <wusamuel@google.com>
Tested-by: Alex Hoh <Alex.Hoh@mediatek.com>
Link: https://patch.msgid.link/20260121163317.505635-1-vincent.guittot@linaro.org
|
|
When calling refcount_inc(&event->mmap_count) inside perf_mmap_rb(), the
following warning is triggered:
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25
PoC:
struct perf_event_attr attr = {0};
int fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);
mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
int victim = syscall(__NR_perf_event_open, &attr, 0, -1, fd,
PERF_FLAG_FD_OUTPUT);
mmap(NULL, 0x3000, PROT_READ | PROT_WRITE, MAP_SHARED, victim, 0);
This occurs when creating a group member event with the flag
PERF_FLAG_FD_OUTPUT. The group leader should be mmap-ed and then mmap-ing
the event triggers the warning.
Since the event has copied the output_event in perf_event_set_output(),
event->rb is set. As a result, perf_mmap_rb() calls
refcount_inc(&event->mmap_count) when event->mmap_count = 0.
Disallow the case when event->mmap_count = 0. This also prevents two
events from updating the same user_page.
Fixes: 448f97fba901 ("perf: Convert mmap() refcounts to refcount_t")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Rosenberg <whrosenb@asu.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260119184956.801238-1-whrosenb@asu.edu
|
|
The "valid" readout delay between the two reads of the watchdog is larger
than the valid delta between the resulting watchdog and clocksource
intervals, which results in false positive watchdog results.
Assume TSC is the clocksource and HPET is the watchdog and both have a
uncertainty margin of 250us (default). The watchdog readout does:
1) wdnow = read(HPET);
2) csnow = read(TSC);
3) wdend = read(HPET);
The valid window for the delta between #1 and #3 is calculated by the
uncertainty margins of the watchdog and the clocksource:
m = 2 * watchdog.uncertainty_margin + cs.uncertainty margin;
which results in 750us for the TSC/HPET case.
The actual interval comparison uses a smaller margin:
m = watchdog.uncertainty_margin + cs.uncertainty margin;
which results in 500us for the TSC/HPET case.
That means the following scenario will trigger the watchdog:
Watchdog cycle N:
1) wdnow[N] = read(HPET);
2) csnow[N] = read(TSC);
3) wdend[N] = read(HPET);
Assume the delay between #1 and #2 is 100us and the delay between #1 and
Watchdog cycle N + 1:
4) wdnow[N + 1] = read(HPET);
5) csnow[N + 1] = read(TSC);
6) wdend[N + 1] = read(HPET);
If the delay between #4 and #6 is within the 750us margin then any delay
between #4 and #5 which is larger than 600us will fail the interval check
and mark the TSC unstable because the intervals are calculated against the
previous value:
wd_int = wdnow[N + 1] - wdnow[N];
cs_int = csnow[N + 1] - csnow[N];
Putting the above delays in place this results in:
cs_int = (wdnow[N + 1] + 610us) - (wdnow[N] + 100us);
-> cs_int = wd_int + 510us;
which is obviously larger than the allowed 500us margin and results in
marking TSC unstable.
Fix this by using the same margin as the interval comparison. If the delay
between two watchdog reads is larger than that, then the readout was either
disturbed by interconnect congestion, NMIs or SMIs.
Fixes: 4ac1dd3245b9 ("clocksource: Set cs_watchdog_read() checks based on .uncertainty_margin")
Reported-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/lkml/20250602223251.496591-1-daniel@quora.org/
Link: https://patch.msgid.link/87bjjxc9dq.ffs@tglx
|
|
Inline bpf_get_current_task() and bpf_get_current_task_btf() for x86_64
to obtain better performance.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260120070555.233486-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
The current comment "Clear TID on mm_release()?" ends with a question
mark, implying uncertainty about whether the TID is actually cleared in
mm_release().
However, the code flow is deterministic. When a task exits, mm_release()
explicitly checks 'tsk->clear_child_tid' and clears.
Since this behavior is unambiguous, remove the confusing question mark and
rephrase the comment to clearly state that TID is cleared in mm_release().
Link: https://lkml.kernel.org/r/20251125000407.24470-1-s9430939@naver.com
Signed-off-by: Minu Jin <s9430939@naver.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
kallsyms_lookup_buildid() copies the symbol name into the given buffer so
that it can be safely read anytime later. But it just copies pointers to
mod->name and mod->build_id which might get reused after the related
struct module gets removed.
The lifetime of struct module is synchronized using RCU. Take the rcu
read lock for the entire __sprint_symbol().
Link: https://lkml.kernel.org/r/20251128135920.217303-8-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
__sprint_symbol() might access an invalid pointer when
kallsyms_lookup_buildid() returns a symbol found by
ftrace_mod_address_lookup().
The ftrace lookup function must set both @modname and @modbuildid the same
way as module_address_lookup().
Link: https://lkml.kernel.org/r/20251128135920.217303-7-pmladek@suse.com
Fixes: 9294523e3768 ("module: add printk formats to add module build ID to stacktraces")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
bpf_address_lookup() has been used only in kallsyms_lookup_buildid(). It
was supposed to set @modname and @modbuildid when the symbol was in a
module.
But it always just cleared @modname because BPF symbols were never in a
module. And it did not clear @modbuildid because the pointer was not
passed.
The wrapper is no longer needed. Both @modname and @modbuildid are now
always initialized to NULL in kallsyms_lookup_buildid().
Remove the wrapper and rename __bpf_address_lookup() to
bpf_address_lookup() because this variant is used everywhere.
[akpm@linux-foundation.org: fix loongarch]
Link: https://lkml.kernel.org/r/20251128135920.217303-6-pmladek@suse.com
Fixes: 9294523e3768 ("module: add printk formats to add module build ID to stacktraces")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Put the code for appending the optional "buildid" into a helper function,
It makes __sprint_symbol() better readable.
Also print a warning when the "modname" is set and the "buildid" isn't.
It might catch a situation when some lookup function in
kallsyms_lookup_buildid() does not handle the "buildid".
Use pr_*_once() to avoid an infinite recursion when the function is called
from printk(). The recursion is rather theoretical but better be on the
safe side.
Link: https://lkml.kernel.org/r/20251128135920.217303-5-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Add a helper function for reading the optional "build_id" member of struct
module. It is going to be used also in ftrace_mod_address_lookup().
Use "#ifdef" instead of "#if IS_ENABLED()" to match the declaration of the
optional field in struct module.
Link: https://lkml.kernel.org/r/20251128135920.217303-4-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
kallsyms_lookup_buildid()
The @modname and @modbuildid optional return parameters are set only when
the symbol is in a module.
Always initialize them so that they do not need to be cleared when the
module is not in a module. It simplifies the logic and makes the code
even slightly more safe.
Note that bpf_address_lookup() function will get updated in a separate
patch.
Link: https://lkml.kernel.org/r/20251128135920.217303-3-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkman <daniel@iogearbox.net>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Luis Chamberalin <mcgrof@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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