| Message ID | 20240228073247.13102-1-haibo.li@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ARM: unwind: fix unwind started from IRQ stack in THUMB2 kernel | expand |
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c index 9d2192156087..89e1f440082c 100644 --- a/arch/arm/kernel/unwind.c +++ b/arch/arm/kernel/unwind.c @@ -482,7 +482,8 @@ int unwind_frame(struct stackframe *frame) ctrl.check_each_pop = 0; - if (prel31_to_addr(&idx->addr_offset) == (u32)&call_with_stack) { + if (prel31_to_addr(&idx->addr_offset) == + ((u32)&call_with_stack & (~0x01))) { /* * call_with_stack() is the only place where we permit SP to * jump from one stack to another, and since we know it is
When unwinds started from IRQ stack,call_with_stack is the only place to do stack switch. It need to identify call_with_stack when unwinding. In thumb2 kernel,it fails to identify call_with_stack. In practice,(u32)&call_with_stack has bit 0 set. prel31_to_addr(&idx->addr_offset) is 0x806ed518, while (u32)&call_with_stack is 0x806ed519. So it is impossible to do stack switch. dump_stack from IRQ stack gets below result: ... call_timer_fn from __run_timers+0x163/0x25c __run_timers from run_timer_softirq+0x15/0x24 run_timer_softirq from __do_softirq+0xe3/0x232 __do_softirq from __irq_exit_rcu+0x3f/0xac __irq_exit_rcu from irq_exit+0x7/0xe irq_exit from call_with_stack+0xd/0x10 ... The stacktrace ends with call_with_stack. Since bit 0 of pc in thumb2 is always 0,skip bit 0 when do compraing. Then we get expected stacktrace: ... call_timer_fn from __run_timers+0x163/0x25c __run_timers from run_timer_softirq+0x15/0x24 run_timer_softirq from __do_softirq+0xe3/0x232 __do_softirq from __irq_exit_rcu+0x3f/0xac __irq_exit_rcu from irq_exit+0x7/0xe irq_exit from call_with_stack+0xd/0x10 call_with_stack from __irq_svc+0x93/0xb6 Exception stack(0xf0875f60 to 0xf0875fa8) 5f60: **** 5f80: **** 5fa0: **** __irq_svc from arch_local_irq_enable+0x2/0x4 arch_local_irq_enable from do_idle+0xad/0x1f6 ... Signed-off-by: Haibo Li <haibo.li@mediatek.com> --- arch/arm/kernel/unwind.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)