[Crash-utility] Re: [PATCH] Fix for "bt" command incorrectly printing "bogus exception frame" warning

Hi Lianbo, thanks for the patch. What is the kernel version of this vmcore?

and could I have "bt 0 -c 8 | tail -n 30" output?

If it's RHEL9, probably that do_softirq is called with this path. cpu_startup_entry do_idle flush_smp_call_function_queue do_softirq but do_idle is skipped as below, I'd like to check just in case..

#20 [ffffbec3c08acff0] do_softirq at ffffffff9730f6ef > --- <IRQ stack> --- > #21 [ffffbec3c022ff28] cpu_startup_entry at ffffffff973684a9 Thanks, Kazu On 2024/03/19 16:59, Lianbo Jiang wrote: > The "bogus exception frame" warning was observed again on a specific > vmcore, and the remaining frame was truncated on X86_64 machine, when > executing the "bt" command as below: > > crash> bt 0 -c 8 > PID: 0 TASK: ffff9948c08f5640 CPU: 8 COMMAND: "swapper/8" > #0 [fffffe1788788e58] crash_nmi_callback at ffffffff972672bb > #1 [fffffe1788788e68] nmi_handle at ffffffff9722eb8e > #2 [fffffe1788788eb0] default_do_nmi at ffffffff97e51cd0 > #3 [fffffe1788788ed0] exc_nmi at ffffffff97e51ee1 > #4 [fffffe1788788ef0] end_repeat_nmi at ffffffff980015f9 > [exception RIP: __update_load_avg_se+13] > RIP: ffffffff9736b16d RSP: ffffbec3c08acc78 RFLAGS: 00000046 > RAX: 0000000000000000 RBX: ffff994c2f2b1a40 RCX: ffffbec3c08acdc0 > RDX: ffff9948e4fe1d80 RSI: ffff994c2f2b1a40 RDI: 0000001d7ad7d55d > RBP: ffffbec3c08acc88 R8: 0000001d921fca6f R9: ffff994c2f2b1328 > R10: 00000000fffd0010 R11: ffffffff98e060c0 R12: 0000001d7ad7d55d > R13: 0000000000000005 R14: ffff994c2f2b19c0 R15: 0000000000000001 > ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 > --- <NMI exception stack> --- > #5 [ffffbec3c08acc78] __update_load_avg_se at ffffffff9736b16d > #6 [ffffbec3c08acce0] enqueue_entity at ffffffff9735c9ab > #7 [ffffbec3c08acd28] enqueue_task_fair at ffffffff9735cef8 > #8 [ffffbec3c08acd60] enqueue_task at ffffffff973481fa > #9 [ffffbec3c08acd88] ttwu_do_activate at ffffffff9734aeed > #10 [ffffbec3c08acdb0] try_to_wake_up at ffffffff9734c7d7 > #11 [ffffbec3c08ace08] __queue_work at ffffffff9732a4d2 > #12 [ffffbec3c08ace50] queue_work_on at ffffffff9732a6a4 > #13 [ffffbec3c08ace60] iomap_dio_bio_end_io at ffffffff976a7b4c > #14 [ffffbec3c08ace90] clone_endio at ffffffffc090315f [dm_mod] > #15 [ffffbec3c08aced0] blk_update_request at ffffffff9779b49d > #16 [ffffbec3c08acf28] scsi_end_request at ffffffff97a3d5a7 > #17 [ffffbec3c08acf58] scsi_io_completion at ffffffff97a3e606 > #18 [ffffbec3c08acf90] blk_complete_reqs at ffffffff977978d0 > #19 [ffffbec3c08acfa0] __do_softirq at ffffffff97e66f7a > #20 [ffffbec3c08acff0] do_softirq at ffffffff9730f6ef > --- <IRQ stack> --- > #21 [ffffbec3c022ff18] do_idle at ffffffff97368288 > [exception RIP: unknown or invalid address] > RIP: 0000000000000000 RSP: 0000000000000000 RFLAGS: 00000000 > RAX: 0000000000000000 RBX: 000000089726a2d0 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: ffffffff9726a3dd R8: 0000000000000000 R9: 0000000000000000 > R10: ffffffff9720015a R11: e48885e126bc1600 R12: 0000000000000000 > R13: ffffffff973684a9 R14: 0000000000000094 R15: 0000000040000000 > ORIG_RAX: 0000000000000000 CS: 0000 SS: 0000 > bt: WARNING: possibly bogus exception frame > crash> > > Actually there is no exception frame, when called from do_softirq(). > With the patch: > > crash> bt 0 -c 8 > PID: 0 TASK: ffff9948c08f5640 CPU: 8 COMMAND: "swapper/8" > #0 [fffffe1788788e58] crash_nmi_callback at ffffffff972672bb > #1 [fffffe1788788e68] nmi_handle at ffffffff9722eb8e > #2 [fffffe1788788eb0] default_do_nmi at ffffffff97e51cd0 > #3 [fffffe1788788ed0] exc_nmi at ffffffff97e51ee1 > #4 [fffffe1788788ef0] end_repeat_nmi at ffffffff980015f9 > [exception RIP: __update_load_avg_se+13] > RIP: ffffffff9736b16d RSP: ffffbec3c08acc78 RFLAGS: 00000046 > RAX: 0000000000000000 RBX: ffff994c2f2b1a40 RCX: ffffbec3c08acdc0 > RDX: ffff9948e4fe1d80 RSI: ffff994c2f2b1a40 RDI: 0000001d7ad7d55d > RBP: ffffbec3c08acc88 R8: 0000001d921fca6f R9: ffff994c2f2b1328 > R10: 00000000fffd0010 R11: ffffffff98e060c0 R12: 0000001d7ad7d55d > R13: 0000000000000005 R14: ffff994c2f2b19c0 R15: 0000000000000001 > ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 > --- <NMI exception stack> --- > #5 [ffffbec3c08acc78] __update_load_avg_se at ffffffff9736b16d > #6 [ffffbec3c08acce0] enqueue_entity at ffffffff9735c9ab > #7 [ffffbec3c08acd28] enqueue_task_fair at ffffffff9735cef8 > #8 [ffffbec3c08acd60] enqueue_task at ffffffff973481fa > #9 [ffffbec3c08acd88] ttwu_do_activate at ffffffff9734aeed > #10 [ffffbec3c08acdb0] try_to_wake_up at ffffffff9734c7d7 > #11 [ffffbec3c08ace08] __queue_work at ffffffff9732a4d2 > #12 [ffffbec3c08ace50] queue_work_on at ffffffff9732a6a4 > #13 [ffffbec3c08ace60] iomap_dio_bio_end_io at ffffffff976a7b4c > #14 [ffffbec3c08ace90] clone_endio at ffffffffc090315f [dm_mod] > #15 [ffffbec3c08aced0] blk_update_request at ffffffff9779b49d > #16 [ffffbec3c08acf28] scsi_end_request at ffffffff97a3d5a7 > #17 [ffffbec3c08acf58] scsi_io_completion at ffffffff97a3e606 > #18 [ffffbec3c08acf90] blk_complete_reqs at ffffffff977978d0 > #19 [ffffbec3c08acfa0] __do_softirq at ffffffff97e66f7a > #20 [ffffbec3c08acff0] do_softirq at ffffffff9730f6ef > --- <IRQ stack> --- > #21 [ffffbec3c022ff28] cpu_startup_entry at ffffffff973684a9 > #22 [ffffbec3c022ff38] start_secondary at ffffffff9726a3dd > #23 [ffffbec3c022ff50] secondary_startup_64_no_verify at ffffffff9720015a > crash> > > Reported-by: Jie Li <jieli(a)redhat.com&gt; > Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com&gt; > --- > x86_64.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/x86_64.c b/x86_64.c > index 502817d3b2bd..c672a0c3e8fc 100644 > --- a/x86_64.c > +++ b/x86_64.c > @@ -3841,11 +3841,12 @@ in_exception_stack: > up -= 1; > bt->instptr = *up; > /* > - * No exception frame when coming from do_softirq_own_stack > - * or call_softirq. > + * No exception frame when coming from do_softirq_own_stack, > + * call_softirq or do_softirq. > */ > if ((sp = value_search(bt->instptr, &offset)) && > - (STREQ(sp->name, "do_softirq_own_stack") || STREQ(sp->name, "call_softirq"))) > + (STREQ(sp->name, "do_softirq_own_stack") || STREQ(sp->name, "call_softirq") > + || STREQ(sp->name, "do_softirq"))) > irq_eframe = 0; > bt->frameptr = 0; > done = FALSE;