[all-commits] [llvm/llvm-project] b9d070: [sanitizer_common] Disable the fast unwinder on Al...

[Matt Turner via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b9d0703f7d6bd040bf317b1099729ba3a421f33c
      https://github.com/llvm/llvm-project/commit/b9d0703f7d6bd040bf317b1099729ba3a421f33c
  Author: Matt Turner <mattst88 at gmail.com>
  Date:   2026-09-09 (Wed, 09 Sep 2026)

  Changed paths:
    M compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h
    M compiler-rt/test/asan/TestCases/complete_stack_trace.c

  Log Message:
  -----------
  [sanitizer_common] Disable the fast unwinder on Alpha Linux (#220231)

BufferedStackTrace::UnwindFast walks the stack assuming frame[0] is the
caller's frame pointer and frame[1] the return address. Alpha chains
neither, so the walk yields a few garbage frames and then stops:
```
  freed by thread T0 here:
      #0 0x020000971274 in free asan_malloc_linux.cpp:51
      #1 0x0200007fa48c  (<unknown module>)
```
Opt Alpha out of the fast unwinder the way Linux/MIPS already is. The
_Unwind_Backtrace based unwinder gives complete traces; with it, GCC's
g++.dg/asan/deep-stack-uaf-1.C passes on alpha-unknown-linux-gnu.



To unsubscribe from these emails, change your notification settings at https://github.com/llvm/llvm-project/settings/notifications