Re: [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault
From: "Paul E. McKenney" <paulmck@kernel.org>
Date: 2025-08-29 15:07:42
Also in:
lkml, oe-lkp
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
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 [off-list ref] | Closes: https://lore.kernel.org/oe-lkp/202508211038.c93e8603-lkp@intel.com (local) [ 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 [off-list ref]
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 [off-list ref]
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)); \ } \ } \