On Tue, Nov 20, 2012 at 11:08 PM, Peter Bergner <berg...@vnet.ibm.com> wrote:
> On Tue, 2012-11-20 at 18:18 +0400, Evgeniy Stepanov wrote:
>
>> I wonder if under some conditions we may get a different number of
>> extra frames (inlining comes to mind). What do you think of removing
>> any number of frames that belong to the runtime library - we have
>> memory layout info for that?
>
> How about the following hack that needs to be cleaned up, but does
> work for me. It scans through the trace looking for the frame pointer
> that is passed in and if it finds it, it pops the stack up to that
> point. If it doesn't find it (a bug?), it just leaves the trace
> alone.
>
> Maybe it fixes the ARM Android issue you just ran into?
>
> Peter
>
>
>
> diff -urpN -X /home/bergner/cvs/dontdiff
> gcc-fsf-mainline-kcc/libsanitizer/asan/asan_linux.cc
> gcc-fsf-mainline-asan/libsanitizer/asan/asan_linux.cc
> --- gcc-fsf-mainline-kcc/libsanitizer/asan/asan_linux.cc 2012-11-20
> 12:52:33.961664485 -0600
> +++ gcc-fsf-mainline-asan/libsanitizer/asan/asan_linux.cc 2012-11-20
> 11:28:00.646245908 -0600
> @@ -141,12 +141,19 @@ uptr Unwind_GetIP(struct _Unwind_Context
> #endif
> }
>
> +uptr Unwind_GetBP(struct _Unwind_Context *ctx) {
> + return _Unwind_GetCFA(ctx);
> +}
> +
> _Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx,
> void *param) {
> StackTrace *b = (StackTrace*)param;
> CHECK(b->size < b->max_size);
> uptr pc = Unwind_GetIP(ctx);
> - b->trace[b->size++] = pc;
> + uptr bp = Unwind_GetBP(ctx);
> + b->trace[b->size] = pc;
> + b->frame[b->size] = bp;
> + b->size++;
> if (b->size == b->max_size) return UNWIND_STOP;
> return UNWIND_CONTINUE;
> }
> @@ -158,8 +165,13 @@ void GetStackTrace(StackTrace *stack, up
> stack->max_size = max_s;
> #if defined(__arm__) || defined(__powerpc__) || defined(__powerpc64__)
> _Unwind_Backtrace(Unwind_Trace, stack);
> - // Pop off the two ASAN functions from the backtrace.
> - stack->PopStackFrames(2);
> + // Attempt to pop off the ASAN functions from the backtrace.
> + uptr cnt;
> + for (cnt = 0; cnt < stack->size; cnt++)
> + if (stack->frame[cnt] == bp) {
> + stack->PopStackFrames(cnt);
> + break;
> + }
> #else
> if (!asan_inited) return;
> if (AsanThread *t = asanThreadRegistry().GetCurrent())
> diff -urpN -X /home/bergner/cvs/dontdiff
> gcc-fsf-mainline-kcc/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
> gcc-fsf-mainline-asan/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
> ---
> gcc-fsf-mainline-kcc/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
> 2012-11-20 11:42:08.834439704 -0600
> +++
> gcc-fsf-mainline-asan/libsanitizer/sanitizer_common/sanitizer_stacktrace.cc
> 2012-11-20 12:59:29.896106625 -0600
> @@ -144,7 +144,8 @@ void StackTrace::PopStackFrames(uptr cou
> CHECK(size > count);
> size -= count;
> for (uptr i = 0; i < size; i++) {
> - trace[i] = trace[i + count];
> + trace[i] = trace[i+count];
> + frame[i] = frame[i+count];
> }
> }
>
> diff -urpN -X /home/bergner/cvs/dontdiff
> gcc-fsf-mainline-kcc/libsanitizer/sanitizer_common/sanitizer_stacktrace.h
> gcc-fsf-mainline-asan/libsanitizer/sanitizer_common/sanitizer_stacktrace.h
> --- gcc-fsf-mainline-kcc/libsanitizer/sanitizer_common/sanitizer_stacktrace.h
> 2012-11-20 11:42:08.821389243 -0600
> +++
> gcc-fsf-mainline-asan/libsanitizer/sanitizer_common/sanitizer_stacktrace.h
> 2012-11-20 11:12:44.551390980 -0600
> @@ -23,6 +23,7 @@ struct StackTrace {
> uptr size;
> uptr max_size;
> uptr trace[kStackTraceMax];
> + uptr frame[kStackTraceMax]; // For use by _Unwind_Backtrace architectures.
This is bad. The objects of this type are already too big, we should
not make them 2x larger.
Hopefully Evgeniy can handle this tomorrow.
--kcc
> static void PrintStack(const uptr *addr, uptr size,
> bool symbolize, const char *strip_file_prefix,
> SymbolizeCallback symbolize_callback);
>
>
