[Crash-utility] [PATCH v2] Fix for "bt" command prints a bogus warning
Currently, the "bt" command may print a bogus exception frame
and the remaining frame will be truncated on x86 64 when using the
"virsh send-key <kvm guest> KEY_LEFTALT KEY_SYSRQ KEY_C" command
to trigger a panic from the KVM host. For example:
crash> bt
PID: 0 TASK: ffff9e7a47e32f00 CPU: 3 COMMAND: "swapper/3"
#0 [ffffba7900118bb8] machine_kexec at ffffffff87e5c2c7
#1 [ffffba7900118c08] __crash_kexec at ffffffff87f9500d
#2 [ffffba7900118cd0] panic at ffffffff87edfff9
#3 [ffffba7900118d50] sysrq_handle_crash at ffffffff883ce2c1
#4 [ffffba7900118d58] __handle_sysrq.cold.15 at ffffffff883ceb56
#5 [ffffba7900118d88] sysrq_filter at ffffffff883ce9a2
#6 [ffffba7900118dc0] input_to_handler at ffffffff884fb0bf
#7 [ffffba7900118df8] input_pass_values at ffffffff884fc1b7
#8 [ffffba7900118e20] input_handle_event at ffffffff884fe278
#9 [ffffba7900118e50] input_event at ffffffff884fe74b
#10 [ffffba7900118e88] atkbd_interrupt at ffffffff88504e2f
#11 [ffffba7900118ee0] serio_interrupt at ffffffff884f7516
#12 [ffffba7900118f10] i8042_interrupt at ffffffff884f8b04
#13 [ffffba7900118f50] __handle_irq_event_percpu at ffffffff87f51430
#14 [ffffba7900118f90] handle_irq_event_percpu at ffffffff87f51590
#15 [ffffba7900118fb8] handle_irq_event at ffffffff87f51616
#16 [ffffba7900118fd8] handle_edge_irq at ffffffff87f559f2
#17 [ffffba7900118ff0] asm_call_on_stack at ffffffff88800fa2
--- <IRQ stack> ---
#18 [ffffba790008bda0] asm_call_on_stack at ffffffff88800fa2
RIP: ffffffffffffffff RSP: 0000000000000124 RFLAGS: 00000003
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffffffff88800c1e RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R8: 0000000000000000 R9: 0000000000000000
R10: 0000000000000000 R11: ffffffff88760555 R12: ffffba790008be08
R13: ffffffff87f18002 R14: ffff9e7a47e32f00 R15: ffff9e7bb6198e00
ORIG_RAX: 0000000000000000 CS: 0003 SS: 0000
bt: WARNING: possibly bogus exception frame
crash>
The following related kernel commits cause the current issue, crash
needs to adjust the value of irq eframe.
Related kernel commits:
[1] v5.8: 931b94145981 ("x86/entry: Provide helpers for executing on the
irqstack")
[2] v5.8: fa5e5c409213 ("x86/entry: Use idtentry for interrupts")
[3] v5.12: 52d743f3b712 ("x86/softirq: Remove indirection in
do_softirq_own_stack()")
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com>
---
x86_64.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/x86_64.c b/x86_64.c
index 7a5d6f050c89..5b671bd97775 100644
--- a/x86_64.c
+++ b/x86_64.c
@@ -3938,6 +3938,11 @@ in_exception_stack:
if (irq_eframe) {
bt->flags |= BT_EXCEPTION_FRAME;
i = (irq_eframe - bt->stackbase)/sizeof(ulong);
+ if (symbol_exists("asm_common_interrupt")) {
+ i -= 1;
+ up = (ulong *)(&bt->stackbuf[i*sizeof(ulong)]);
+ bt->instptr = *up;
+ }
x86_64_print_stack_entry(bt, ofp, level, i, bt->instptr);
bt->flags &= ~(ulonglong)BT_EXCEPTION_FRAME;
cs = x86_64_exception_frame(EFRAME_PRINT|EFRAME_CS, 0,
@@ -6521,6 +6526,14 @@ x86_64_irq_eframe_link_init(void)
else
return;
+ if (symbol_exists("asm_common_interrupt")) {
+ if (symbol_exists("asm_call_on_stack"))
+ machdep->machspec->irq_eframe_link = -64;
+ else
+ machdep->machspec->irq_eframe_link = -32;
+ return;
+ }
+
if (THIS_KERNEL_VERSION < LINUX(2,6,9))
return;
--
2.37.1