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@redhat.com>
> Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
> ---
>   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;