From ce47cb8dabb56c88e2d753026a9fdc83f83a5f5d Mon Sep 17 00:00:00 2001 From: Lianbo Jiang Date: Tue, 19 Mar 2024 15:59:31 +0800 Subject: [PATCH] x86_64: Fix for "bt" command incorrectly printing "bogus exception frame" warning 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 --- --- #5 [ffffbec3c08acc78] __update_load_avg_se at ffffffff9736b16d #6 [ffffbec3c08acce0] enqueue_entity at ffffffff9735c9ab #7 [ffffbec3c08acd28] enqueue_task_fair at ffffffff9735cef8 ... #18 [ffffbec3c08acf90] blk_complete_reqs at ffffffff977978d0 #19 [ffffbec3c08acfa0] __do_softirq at ffffffff97e66f7a #20 [ffffbec3c08acff0] do_softirq at ffffffff9730f6ef --- --- #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 ... #18 [ffffbec3c08acf90] blk_complete_reqs at ffffffff977978d0 #19 [ffffbec3c08acfa0] __do_softirq at ffffffff97e66f7a #20 [ffffbec3c08acff0] do_softirq at ffffffff9730f6ef --- --- #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 Signed-off-by: Lianbo Jiang --- x86_64.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/x86_64.c b/x86_64.c index 502817d3..aec82b03 100644 --- a/x86_64.c +++ b/x86_64.c @@ -3841,11 +3841,12 @@ x86_64_low_budget_back_trace_cmd(struct bt_info *bt_in) 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, + * do_softirq_own_stack or call_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") || STREQ(sp->name, "do_softirq_own_stack") || + STREQ(sp->name, "call_softirq"))) irq_eframe = 0; bt->frameptr = 0; done = FALSE;