Messages in this thread Patch in this message | | | From | Wang Kai <> | Subject | [PATCH] ARM:stacktrace: make stacktrace skip always right. | Date | Thu, 11 Sep 2014 17:02:23 +0800 |
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This patch is for commit 3683f44c42e991d313dc301504ee0fca1aeb8580, that makes stacktrace NOT begin from stacktrace self function, which are: __save_stack_trace and save_stack_trace.
But save_stack_trace will NOT have stacktrace information when build with '-O2', assemble code looks like below: 00000154 <save_stack_trace>: 154: e1a0200d mov r2, sp 158: e1a01000 mov r1, r0 15c: e3c23d7f bic r3, r2, #8128 ; 0x1fc0 160: e3a02000 mov r2, #0 164: e3c3303f bic r3, r3, #63 ; 0x3f 168: e593000c ldr r0, [r3, #12] 16c: eaffffd0 b b4 <__save_stack_trace>
In this situation, the "data.skip +=2" operation will skip the last user call function, make user stacktrace strange/incorrect.
To fix this, we have to make sure save_stack_trace has stacktrace info, then skip 2 function will be OK.
Signed-off-by: Wang Kai <morgan.wang@huawei.com> --- arch/arm/kernel/stacktrace.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index 6582c4a..1eb1b5ae 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -134,6 +134,7 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) void save_stack_trace(struct stack_trace *trace) { __save_stack_trace(current, trace, 0); + asm volatile("" : : : "memory"); } EXPORT_SYMBOL_GPL(save_stack_trace); #endif -- 1.8.5.5
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