[llvm-commits] [compiler-rt] r168046 - in /compiler-rt/trunk/lib/asan: asan_allocator.cc asan_internal.h asan_report.cc asan_thread.cc
Alexey Samsonov
samsonov at google.com
Tue Nov 20 01:41:42 PST 2012
This fix is completely wrong: FakeStack::AddrIsInFakeStack(addr)
doesn't return a fake stack frame containing "addr", but a pointer to
a mapped memory region containing a bunch of fake stack frames of the same
size.
On Thu, Nov 15, 2012 at 7:45 PM, Kostya Serebryany <kcc at google.com> wrote:
> Thanks!
>
>
> On Thu, Nov 15, 2012 at 7:24 AM, Alexander Potapenko <glider at google.com>wrote:
>
>> Author: glider
>> Date: Thu Nov 15 09:24:42 2012
>> New Revision: 168046
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=168046&view=rev
>> Log:
>> [ASan] Revert r168040 and r168043 and take a cleaner solution suggested
>> by Kostya: return the known frame name for fake stack instead of looking it
>> up.
>>
>> Modified:
>> compiler-rt/trunk/lib/asan/asan_allocator.cc
>> compiler-rt/trunk/lib/asan/asan_internal.h
>> compiler-rt/trunk/lib/asan/asan_report.cc
>> compiler-rt/trunk/lib/asan/asan_thread.cc
>>
>> Modified: compiler-rt/trunk/lib/asan/asan_allocator.cc
>> URL:
>> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_allocator.cc?rev=168046&r1=168045&r2=168046&view=diff
>>
>> ==============================================================================
>> --- compiler-rt/trunk/lib/asan/asan_allocator.cc (original)
>> +++ compiler-rt/trunk/lib/asan/asan_allocator.cc Thu Nov 15 09:24:42 2012
>> @@ -998,10 +998,6 @@
>> CHECK(fake_frame->descr != 0);
>> CHECK(fake_frame->size_minus_one == size - 1);
>> PoisonShadow(ptr, size, kAsanStackAfterReturnMagic);
>> - CHECK(size >= SHADOW_GRANULARITY);
>> - // Poison the leftmost shadow byte with a special value so that we can
>> find
>> - // the beginning of the fake frame when reporting an error.
>> - PoisonShadow(ptr, SHADOW_GRANULARITY, kAsanStackAfterReturnLeftMagic);
>> }
>>
>> } // namespace __asan
>>
>> Modified: compiler-rt/trunk/lib/asan/asan_internal.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_internal.h?rev=168046&r1=168045&r2=168046&view=diff
>>
>> ==============================================================================
>> --- compiler-rt/trunk/lib/asan/asan_internal.h (original)
>> +++ compiler-rt/trunk/lib/asan/asan_internal.h Thu Nov 15 09:24:42 2012
>> @@ -160,7 +160,6 @@
>> const int kAsanStackAfterReturnMagic = 0xf5;
>> const int kAsanInitializationOrderMagic = 0xf6;
>> const int kAsanUserPoisonedMemoryMagic = 0xf7;
>> -const int kAsanStackAfterReturnLeftMagic = 0xf8;
>> const int kAsanGlobalRedzoneMagic = 0xf9;
>> const int kAsanInternalHeapMagic = 0xfe;
>>
>>
>> Modified: compiler-rt/trunk/lib/asan/asan_report.cc
>> URL:
>> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_report.cc?rev=168046&r1=168045&r2=168046&view=diff
>>
>> ==============================================================================
>> --- compiler-rt/trunk/lib/asan/asan_report.cc (original)
>> +++ compiler-rt/trunk/lib/asan/asan_report.cc Thu Nov 15 09:24:42 2012
>> @@ -450,7 +450,6 @@
>> bug_descr = "stack-buffer-overflow";
>> break;
>> case kAsanStackAfterReturnMagic:
>> - case kAsanStackAfterReturnLeftMagic:
>> bug_descr = "stack-use-after-return";
>> break;
>> case kAsanUserPoisonedMemoryMagic:
>>
>> Modified: compiler-rt/trunk/lib/asan/asan_thread.cc
>> URL:
>> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_thread.cc?rev=168046&r1=168045&r2=168046&view=diff
>>
>> ==============================================================================
>> --- compiler-rt/trunk/lib/asan/asan_thread.cc (original)
>> +++ compiler-rt/trunk/lib/asan/asan_thread.cc Thu Nov 15 09:24:42 2012
>> @@ -118,41 +118,35 @@
>>
>> const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset) {
>> uptr bottom = 0;
>> - bool is_fake_stack = false;
>> if (AddrIsInStack(addr)) {
>> bottom = stack_bottom();
>> } else {
>> bottom = fake_stack().AddrIsInFakeStack(addr);
>> CHECK(bottom);
>> - is_fake_stack = true;
>> + *offset = addr - bottom;
>> + return (const char *)((uptr*)bottom)[1];
>> }
>> uptr aligned_addr = addr & ~(__WORDSIZE/8 - 1); // align addr.
>> u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr);
>> u8 *shadow_bottom = (u8*)MemToShadow(bottom);
>>
>> while (shadow_ptr >= shadow_bottom &&
>> - *shadow_ptr != kAsanStackLeftRedzoneMagic &&
>> - *shadow_ptr != kAsanStackAfterReturnLeftMagic) {
>> + *shadow_ptr != kAsanStackLeftRedzoneMagic) {
>> shadow_ptr--;
>> }
>>
>> while (shadow_ptr >= shadow_bottom &&
>> - (*shadow_ptr == kAsanStackLeftRedzoneMagic ||
>> - *shadow_ptr == kAsanStackAfterReturnLeftMagic)) {
>> + *shadow_ptr == kAsanStackLeftRedzoneMagic) {
>> shadow_ptr--;
>> }
>>
>> if (shadow_ptr < shadow_bottom) {
>> - // If we're one byte below the fake stack bottom, we've found the
>> frame.
>> - if (!is_fake_stack || (*shadow_bottom !=
>> kAsanStackAfterReturnLeftMagic)) {
>> - *offset = 0;
>> - return "UNKNOWN";
>> - }
>> + *offset = 0;
>> + return "UNKNOWN";
>> }
>>
>> uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1));
>> - CHECK((ptr[0] == kCurrentStackFrameMagic) ||
>> - (is_fake_stack && ptr[0] == kRetiredStackFrameMagic));
>> + CHECK(ptr[0] == kCurrentStackFrameMagic);
>> *offset = addr - (uptr)ptr;
>> return (const char*)ptr[1];
>> }
>>
>>
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--
Alexey Samsonov, MSK
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