* [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault
@ 2025-08-21 5:26 kernel test robot
2025-08-29 15:07 ` Paul E. McKenney
0 siblings, 1 reply; 6+ messages in thread
From: kernel test robot @ 2025-08-21 5:26 UTC (permalink / raw)
To: Paul E. McKenney
Cc: oe-lkp, lkp, linux-kernel, Mathieu Desnoyers, Steven Rostedt,
Sebastian Andrzej Siewior, linux-trace-kernel, oliver.sang
hi, Paul,
we also noticed there is similar commit in newer branch
dev.2025.08.14a
dev.2025.08.19a
but we didn't finish any bisect for them so far.
if the issue is already known and fixed in newer version, please just ignore
this report. sorry if any inconvenience.
below full report FYI.
Hello,
kernel test robot noticed "WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault" on:
commit: 364ac25d46eea504eb90229d2a1f92e18c1a1eae ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast")
https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git dev.2025.08.13a
in testcase: boot
config: i386-randconfig-004-20250819
compiler: clang-20
test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
(please refer to attached dmesg/kmsg for entire log/backtrace)
+----------------------------------------------------+------------+------------+
| | c0e2a3f449 | 364ac25d46 |
+----------------------------------------------------+------------+------------+
| WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault | 0 | 12 |
| EIP:do_user_addr_fault | 0 | 12 |
| BUG:kernel_NULL_pointer_dereference,address | 0 | 12 |
| Oops | 0 | 12 |
| EIP:do_int80_syscall_32 | 0 | 12 |
| Kernel_panic-not_syncing:Fatal_exception | 0 | 12 |
+----------------------------------------------------+------------+------------+
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202508211038.c93e8603-lkp@intel.com
[ 5.974959][ T117] ------------[ cut here ]------------
[ 5.975530][ T117] WARNING: CPU: 1 PID: 117 at arch/x86/mm/fault.c:1276 do_user_addr_fault (ld-temp.o:?)
[ 5.976496][ T117] Modules linked in:
[ 5.976924][ T117] CPU: 1 UID: 0 PID: 117 Comm: sh Not tainted 6.17.0-rc1-00010-g364ac25d46ee #1 NONE 7aaffa6b74f3c55be0a24cdbe6593fcd4ccf301d
[ 5.978263][ T117] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 5.979306][ T117] EIP: do_user_addr_fault (ld-temp.o:?)
[ 5.979859][ T117] Code: 15 fe ff ff 89 f9 ff 75 f0 e8 96 04 00 00 83 c4 04 e9 03 fe ff ff 89 f9 89 da ff 75 f0 e8 72 01 00 00 83 c4 04 e9 ef fd ff ff <0f> 0b 89 f9 89 da ff 75 f0 e8 fc 03 00 00 83 c4 04 e9 d9 fd ff ff
All code
========
0: 15 fe ff ff 89 adc $0x89fffffe,%eax
5: f9 stc
6: ff 75 f0 push -0x10(%rbp)
9: e8 96 04 00 00 call 0x4a4
e: 83 c4 04 add $0x4,%esp
11: e9 03 fe ff ff jmp 0xfffffffffffffe19
16: 89 f9 mov %edi,%ecx
18: 89 da mov %ebx,%edx
1a: ff 75 f0 push -0x10(%rbp)
1d: e8 72 01 00 00 call 0x194
22: 83 c4 04 add $0x4,%esp
25: e9 ef fd ff ff jmp 0xfffffffffffffe19
2a:* 0f 0b ud2 <-- trapping instruction
2c: 89 f9 mov %edi,%ecx
2e: 89 da mov %ebx,%edx
30: ff 75 f0 push -0x10(%rbp)
33: e8 fc 03 00 00 call 0x434
38: 83 c4 04 add $0x4,%esp
3b: e9 d9 fd ff ff jmp 0xfffffffffffffe19
Code starting with the faulting instruction
===========================================
0: 0f 0b ud2
2: 89 f9 mov %edi,%ecx
4: 89 da mov %ebx,%edx
6: ff 75 f0 push -0x10(%rbp)
9: e8 fc 03 00 00 call 0x40a
e: 83 c4 04 add $0x4,%esp
11: e9 d9 fd ff ff jmp 0xfffffffffffffdef
[ 5.981783][ T117] EAX: 80000000 EBX: 00000000 ECX: 00000000 EDX: 4875de00
[ 5.982461][ T117] ESI: 46bf1f14 EDI: 46bf1f14 EBP: 46bf1ef0 ESP: 46bf1ec4
[ 5.983152][ T117] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010046
[ 5.983885][ T117] CR0: 80050033 CR2: 00000004 CR3: 06fc8000 CR4: 00040690
[ 5.984575][ T117] Call Trace:
[ 5.984911][ T117] ? exc_page_fault (ld-temp.o:?)
[ 5.985376][ T117] ? pvclock_clocksource_read_nowd (ld-temp.o:?)
[ 5.985971][ T117] ? handle_exception (arch/x86/entry/entry_32.S:1048)
[ 5.986454][ T117] ? do_int80_syscall_32 (ld-temp.o:?)
[ 5.986948][ T117] ? entry_INT80_32 (arch/x86/entry/entry_32.S:945)
[ 5.987410][ T117] ? insn_get_code_seg_params (ld-temp.o:?)
[ 5.987948][ T117] ? pvclock_clocksource_read_nowd (ld-temp.o:?)
[ 5.988547][ T117] ? do_int80_syscall_32 (ld-temp.o:?)
[ 5.989050][ T117] ? pvclock_clocksource_read_nowd (ld-temp.o:?)
[ 5.989645][ T117] ? do_int80_syscall_32 (ld-temp.o:?)
[ 5.990146][ T117] ? entry_INT80_32 (arch/x86/entry/entry_32.S:945)
[ 5.990611][ T117] ? irqentry_exit (ld-temp.o:?)
[ 5.991053][ T117] ? exc_page_fault (ld-temp.o:?)
[ 5.991512][ T117] ? entry_INT80_32 (arch/x86/entry/entry_32.S:945)
[ 5.991915][ T117] irq event stamp: 5810
[ 5.992173][ T117] hardirqs last enabled at (5809): do_wait (ld-temp.o:?)
[ 5.992686][ T117] hardirqs last disabled at (5810): do_int80_syscall_32 (ld-temp.o:?)
[ 5.993245][ T117] softirqs last enabled at (5692): local_bh_enable (ld-temp.o:?)
[ 5.993776][ T117] softirqs last disabled at (5690): local_bh_disable (ld-temp.o:?)
[ 5.994304][ T117] ---[ end trace 0000000000000000 ]---
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250821/202508211038.c93e8603-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault
2025-08-21 5:26 [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault kernel test robot
@ 2025-08-29 15:07 ` Paul E. McKenney
2025-09-03 1:34 ` Oliver Sang
0 siblings, 1 reply; 6+ messages in thread
From: Paul E. McKenney @ 2025-08-29 15:07 UTC (permalink / raw)
To: kernel test robot
Cc: oe-lkp, lkp, linux-kernel, Mathieu Desnoyers, Steven Rostedt,
Sebastian Andrzej Siewior, linux-trace-kernel
On Thu, Aug 21, 2025 at 01:26:45PM +0800, kernel test robot wrote:
>
> hi, Paul,
>
> we also noticed there is similar commit in newer branch
> dev.2025.08.14a
> dev.2025.08.19a
> but we didn't finish any bisect for them so far.
>
> if the issue is already known and fixed in newer version, please just ignore
> this report. sorry if any inconvenience.
>
> below full report FYI.
>
>
> Hello,
>
> kernel test robot noticed "WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault" on:
>
> commit: 364ac25d46eea504eb90229d2a1f92e18c1a1eae ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast")
> https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git dev.2025.08.13a
>
> in testcase: boot
>
> config: i386-randconfig-004-20250819
> compiler: clang-20
> test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
>
> (please refer to attached dmesg/kmsg for entire log/backtrace)
Thank you for your testing efforts, and apologies for being slow!
Could you please try the diagnostic patch at the end of this email?
Thanx, Paul
> +----------------------------------------------------+------------+------------+
> | | c0e2a3f449 | 364ac25d46 |
> +----------------------------------------------------+------------+------------+
> | WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault | 0 | 12 |
> | EIP:do_user_addr_fault | 0 | 12 |
> | BUG:kernel_NULL_pointer_dereference,address | 0 | 12 |
> | Oops | 0 | 12 |
> | EIP:do_int80_syscall_32 | 0 | 12 |
> | Kernel_panic-not_syncing:Fatal_exception | 0 | 12 |
> +----------------------------------------------------+------------+------------+
>
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@intel.com>
> | Closes: https://lore.kernel.org/oe-lkp/202508211038.c93e8603-lkp@intel.com
>
>
> [ 5.974959][ T117] ------------[ cut here ]------------
> [ 5.975530][ T117] WARNING: CPU: 1 PID: 117 at arch/x86/mm/fault.c:1276 do_user_addr_fault (ld-temp.o:?)
> [ 5.976496][ T117] Modules linked in:
> [ 5.976924][ T117] CPU: 1 UID: 0 PID: 117 Comm: sh Not tainted 6.17.0-rc1-00010-g364ac25d46ee #1 NONE 7aaffa6b74f3c55be0a24cdbe6593fcd4ccf301d
> [ 5.978263][ T117] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> [ 5.979306][ T117] EIP: do_user_addr_fault (ld-temp.o:?)
> [ 5.979859][ T117] Code: 15 fe ff ff 89 f9 ff 75 f0 e8 96 04 00 00 83 c4 04 e9 03 fe ff ff 89 f9 89 da ff 75 f0 e8 72 01 00 00 83 c4 04 e9 ef fd ff ff <0f> 0b 89 f9 89 da ff 75 f0 e8 fc 03 00 00 83 c4 04 e9 d9 fd ff ff
> All code
> ========
> 0: 15 fe ff ff 89 adc $0x89fffffe,%eax
> 5: f9 stc
> 6: ff 75 f0 push -0x10(%rbp)
> 9: e8 96 04 00 00 call 0x4a4
> e: 83 c4 04 add $0x4,%esp
> 11: e9 03 fe ff ff jmp 0xfffffffffffffe19
> 16: 89 f9 mov %edi,%ecx
> 18: 89 da mov %ebx,%edx
> 1a: ff 75 f0 push -0x10(%rbp)
> 1d: e8 72 01 00 00 call 0x194
> 22: 83 c4 04 add $0x4,%esp
> 25: e9 ef fd ff ff jmp 0xfffffffffffffe19
> 2a:* 0f 0b ud2 <-- trapping instruction
> 2c: 89 f9 mov %edi,%ecx
> 2e: 89 da mov %ebx,%edx
> 30: ff 75 f0 push -0x10(%rbp)
> 33: e8 fc 03 00 00 call 0x434
> 38: 83 c4 04 add $0x4,%esp
> 3b: e9 d9 fd ff ff jmp 0xfffffffffffffe19
>
> Code starting with the faulting instruction
> ===========================================
> 0: 0f 0b ud2
> 2: 89 f9 mov %edi,%ecx
> 4: 89 da mov %ebx,%edx
> 6: ff 75 f0 push -0x10(%rbp)
> 9: e8 fc 03 00 00 call 0x40a
> e: 83 c4 04 add $0x4,%esp
> 11: e9 d9 fd ff ff jmp 0xfffffffffffffdef
> [ 5.981783][ T117] EAX: 80000000 EBX: 00000000 ECX: 00000000 EDX: 4875de00
> [ 5.982461][ T117] ESI: 46bf1f14 EDI: 46bf1f14 EBP: 46bf1ef0 ESP: 46bf1ec4
> [ 5.983152][ T117] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00010046
> [ 5.983885][ T117] CR0: 80050033 CR2: 00000004 CR3: 06fc8000 CR4: 00040690
> [ 5.984575][ T117] Call Trace:
> [ 5.984911][ T117] ? exc_page_fault (ld-temp.o:?)
> [ 5.985376][ T117] ? pvclock_clocksource_read_nowd (ld-temp.o:?)
> [ 5.985971][ T117] ? handle_exception (arch/x86/entry/entry_32.S:1048)
> [ 5.986454][ T117] ? do_int80_syscall_32 (ld-temp.o:?)
> [ 5.986948][ T117] ? entry_INT80_32 (arch/x86/entry/entry_32.S:945)
> [ 5.987410][ T117] ? insn_get_code_seg_params (ld-temp.o:?)
> [ 5.987948][ T117] ? pvclock_clocksource_read_nowd (ld-temp.o:?)
> [ 5.988547][ T117] ? do_int80_syscall_32 (ld-temp.o:?)
> [ 5.989050][ T117] ? pvclock_clocksource_read_nowd (ld-temp.o:?)
> [ 5.989645][ T117] ? do_int80_syscall_32 (ld-temp.o:?)
> [ 5.990146][ T117] ? entry_INT80_32 (arch/x86/entry/entry_32.S:945)
> [ 5.990611][ T117] ? irqentry_exit (ld-temp.o:?)
> [ 5.991053][ T117] ? exc_page_fault (ld-temp.o:?)
> [ 5.991512][ T117] ? entry_INT80_32 (arch/x86/entry/entry_32.S:945)
> [ 5.991915][ T117] irq event stamp: 5810
> [ 5.992173][ T117] hardirqs last enabled at (5809): do_wait (ld-temp.o:?)
> [ 5.992686][ T117] hardirqs last disabled at (5810): do_int80_syscall_32 (ld-temp.o:?)
> [ 5.993245][ T117] softirqs last enabled at (5692): local_bh_enable (ld-temp.o:?)
> [ 5.993776][ T117] softirqs last disabled at (5690): local_bh_disable (ld-temp.o:?)
> [ 5.994304][ T117] ---[ end trace 0000000000000000 ]---
>
>
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20250821/202508211038.c93e8603-lkp@intel.com
>
>
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
commit 2d6142ce44dca77fb173bb96850634b169277214
Author: Paul E. McKenney <paulmck@kernel.org>
Date: Thu Aug 28 12:56:42 2025 -0700
EXP tracing: Diagnostic for __DECLARE_TRACE() use of SRCU-fast
This patch is intended to test the theory that preemption needs to be
disabled in some portion of the tracing infrastructure extending from
the __DECLARE_TRACE() macro to the target BPF program.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index a22c1ab88560b8..c422e4c5ed51ed 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -273,7 +273,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
static inline void __do_trace_##name(proto) \
{ \
if (cond) { \
- guard(srcu_fast_notrace)(&tracepoint_srcu); \
+ guard(preempt_notrace)(); \
__DO_TRACE_CALL(name, TP_ARGS(args)); \
} \
} \
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault
2025-08-29 15:07 ` Paul E. McKenney
@ 2025-09-03 1:34 ` Oliver Sang
2025-09-03 10:31 ` Paul E. McKenney
0 siblings, 1 reply; 6+ messages in thread
From: Oliver Sang @ 2025-09-03 1:34 UTC (permalink / raw)
To: Paul E. McKenney
Cc: oe-lkp, lkp, linux-kernel, Mathieu Desnoyers, Steven Rostedt,
Sebastian Andrzej Siewior, linux-trace-kernel, oliver.sang
hi, Paul,
On Fri, Aug 29, 2025 at 08:07:41AM -0700, Paul E. McKenney wrote:
> On Thu, Aug 21, 2025 at 01:26:45PM +0800, kernel test robot wrote:
> >
> > hi, Paul,
> >
> > we also noticed there is similar commit in newer branch
> > dev.2025.08.14a
> > dev.2025.08.19a
> > but we didn't finish any bisect for them so far.
> >
> > if the issue is already known and fixed in newer version, please just ignore
> > this report. sorry if any inconvenience.
> >
> > below full report FYI.
> >
> >
> > Hello,
> >
> > kernel test robot noticed "WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault" on:
> >
> > commit: 364ac25d46eea504eb90229d2a1f92e18c1a1eae ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast")
> > https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git dev.2025.08.13a
> >
> > in testcase: boot
> >
> > config: i386-randconfig-004-20250819
> > compiler: clang-20
> > test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
> >
> > (please refer to attached dmesg/kmsg for entire log/backtrace)
>
> Thank you for your testing efforts, and apologies for being slow!
>
> Could you please try the diagnostic patch at the end of this email?
>
> Thanx, Paul
by applying the patch, the issue gone. but since you said this is a 'diagnostic
patch', not sure if it's a real fix. anyway:
Tested-by: kernel test robot <oliver.sang@intel.com>
[...]
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <oliver.sang@intel.com>
> > | Closes: https://lore.kernel.org/oe-lkp/202508211038.c93e8603-lkp@intel.com
[...]
> > The kernel config and materials to reproduce are available at:
> > https://download.01.org/0day-ci/archive/20250821/202508211038.c93e8603-lkp@intel.com
> > --
> > 0-DAY CI Kernel Test Service
> > https://github.com/intel/lkp-tests/wiki
>
>
> commit 2d6142ce44dca77fb173bb96850634b169277214
> Author: Paul E. McKenney <paulmck@kernel.org>
> Date: Thu Aug 28 12:56:42 2025 -0700
>
> EXP tracing: Diagnostic for __DECLARE_TRACE() use of SRCU-fast
>
> This patch is intended to test the theory that preemption needs to be
> disabled in some portion of the tracing infrastructure extending from
> the __DECLARE_TRACE() macro to the target BPF program.
>
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
>
> diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
> index a22c1ab88560b8..c422e4c5ed51ed 100644
> --- a/include/linux/tracepoint.h
> +++ b/include/linux/tracepoint.h
> @@ -273,7 +273,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
> static inline void __do_trace_##name(proto) \
> { \
> if (cond) { \
> - guard(srcu_fast_notrace)(&tracepoint_srcu); \
> + guard(preempt_notrace)(); \
> __DO_TRACE_CALL(name, TP_ARGS(args)); \
> } \
> } \
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault
2025-09-03 1:34 ` Oliver Sang
@ 2025-09-03 10:31 ` Paul E. McKenney
2025-09-03 15:31 ` Steven Rostedt
0 siblings, 1 reply; 6+ messages in thread
From: Paul E. McKenney @ 2025-09-03 10:31 UTC (permalink / raw)
To: Oliver Sang
Cc: oe-lkp, lkp, linux-kernel, Mathieu Desnoyers, Steven Rostedt,
Sebastian Andrzej Siewior, linux-trace-kernel
On Wed, Sep 03, 2025 at 09:34:38AM +0800, Oliver Sang wrote:
> hi, Paul,
>
> On Fri, Aug 29, 2025 at 08:07:41AM -0700, Paul E. McKenney wrote:
> > On Thu, Aug 21, 2025 at 01:26:45PM +0800, kernel test robot wrote:
> > >
> > > hi, Paul,
> > >
> > > we also noticed there is similar commit in newer branch
> > > dev.2025.08.14a
> > > dev.2025.08.19a
> > > but we didn't finish any bisect for them so far.
> > >
> > > if the issue is already known and fixed in newer version, please just ignore
> > > this report. sorry if any inconvenience.
> > >
> > > below full report FYI.
> > >
> > >
> > > Hello,
> > >
> > > kernel test robot noticed "WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault" on:
> > >
> > > commit: 364ac25d46eea504eb90229d2a1f92e18c1a1eae ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast")
> > > https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git dev.2025.08.13a
> > >
> > > in testcase: boot
> > >
> > > config: i386-randconfig-004-20250819
> > > compiler: clang-20
> > > test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G
> > >
> > > (please refer to attached dmesg/kmsg for entire log/backtrace)
> >
> > Thank you for your testing efforts, and apologies for being slow!
> >
> > Could you please try the diagnostic patch at the end of this email?
> >
> > Thanx, Paul
>
> by applying the patch, the issue gone. but since you said this is a 'diagnostic
> patch', not sure if it's a real fix. anyway:
>
> Tested-by: kernel test robot <oliver.sang@intel.com>
Thank you very much! This tells me that something on the code path from
the tracepoint to the BPF program needs to have preemption disabled.
I will leave the diagnostic patch in my tree, and will be looking into
what the real fix should be.
Thanx, Paul
> [...]
>
> > > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > > the same patch/commit), kindly add following tags
> > > | Reported-by: kernel test robot <oliver.sang@intel.com>
> > > | Closes: https://lore.kernel.org/oe-lkp/202508211038.c93e8603-lkp@intel.com
>
> [...]
>
> > > The kernel config and materials to reproduce are available at:
> > > https://download.01.org/0day-ci/archive/20250821/202508211038.c93e8603-lkp@intel.com
> > > --
> > > 0-DAY CI Kernel Test Service
> > > https://github.com/intel/lkp-tests/wiki
> >
> >
> > commit 2d6142ce44dca77fb173bb96850634b169277214
> > Author: Paul E. McKenney <paulmck@kernel.org>
> > Date: Thu Aug 28 12:56:42 2025 -0700
> >
> > EXP tracing: Diagnostic for __DECLARE_TRACE() use of SRCU-fast
> >
> > This patch is intended to test the theory that preemption needs to be
> > disabled in some portion of the tracing infrastructure extending from
> > the __DECLARE_TRACE() macro to the target BPF program.
> >
> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> >
> > diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
> > index a22c1ab88560b8..c422e4c5ed51ed 100644
> > --- a/include/linux/tracepoint.h
> > +++ b/include/linux/tracepoint.h
> > @@ -273,7 +273,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
> > static inline void __do_trace_##name(proto) \
> > { \
> > if (cond) { \
> > - guard(srcu_fast_notrace)(&tracepoint_srcu); \
> > + guard(preempt_notrace)(); \
> > __DO_TRACE_CALL(name, TP_ARGS(args)); \
> > } \
> > } \
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault
2025-09-03 10:31 ` Paul E. McKenney
@ 2025-09-03 15:31 ` Steven Rostedt
2025-09-05 13:43 ` Paul E. McKenney
0 siblings, 1 reply; 6+ messages in thread
From: Steven Rostedt @ 2025-09-03 15:31 UTC (permalink / raw)
To: Paul E. McKenney
Cc: Oliver Sang, oe-lkp, lkp, linux-kernel, Mathieu Desnoyers,
Sebastian Andrzej Siewior, linux-trace-kernel
On Wed, 3 Sep 2025 03:31:31 -0700
"Paul E. McKenney" <paulmck@kernel.org> wrote:
> > by applying the patch, the issue gone. but since you said this is a 'diagnostic
> > patch', not sure if it's a real fix. anyway:
> >
> > Tested-by: kernel test robot <oliver.sang@intel.com>
>
> Thank you very much! This tells me that something on the code path from
> the tracepoint to the BPF program needs to have preemption disabled.
> I will leave the diagnostic patch in my tree, and will be looking into
> what the real fix should be.
Was it a BPF program that triggered this? I couldn't get that from the
backtrace. Also, is this only a x86 32bit issue?
-- Steve
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault
2025-09-03 15:31 ` Steven Rostedt
@ 2025-09-05 13:43 ` Paul E. McKenney
0 siblings, 0 replies; 6+ messages in thread
From: Paul E. McKenney @ 2025-09-05 13:43 UTC (permalink / raw)
To: Steven Rostedt
Cc: Oliver Sang, oe-lkp, lkp, linux-kernel, Mathieu Desnoyers,
Sebastian Andrzej Siewior, linux-trace-kernel
On Wed, Sep 03, 2025 at 11:31:12AM -0400, Steven Rostedt wrote:
> On Wed, 3 Sep 2025 03:31:31 -0700
> "Paul E. McKenney" <paulmck@kernel.org> wrote:
>
> > > by applying the patch, the issue gone. but since you said this is a 'diagnostic
> > > patch', not sure if it's a real fix. anyway:
> > >
> > > Tested-by: kernel test robot <oliver.sang@intel.com>
> >
> > Thank you very much! This tells me that something on the code path from
> > the tracepoint to the BPF program needs to have preemption disabled.
> > I will leave the diagnostic patch in my tree, and will be looking into
> > what the real fix should be.
>
> Was it a BPF program that triggered this? I couldn't get that from the
> backtrace. Also, is this only a x86 32bit issue?
Excellent question, now that you mention it! Your thought is that
one of the other preemption-disablings might need to be moved?
Thanx, Paul
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2025-09-05 13:43 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2025-08-21 5:26 [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault kernel test robot
2025-08-29 15:07 ` Paul E. McKenney
2025-09-03 1:34 ` Oliver Sang
2025-09-03 10:31 ` Paul E. McKenney
2025-09-03 15:31 ` Steven Rostedt
2025-09-05 13:43 ` Paul E. McKenney
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