release/19.x: [sanitizer_common] Fix UnwindFast on SPARC (#101634) #101848
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@MaskRay What do you think about merging this PR to the release branch? |
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@llvm/pr-subscribers-compiler-rt-sanitizer Author: None (llvmbot) ChangesBackport 3368a32 Requested by: @rorth Full diff: https://github.com/llvm/llvm-project/pull/101848.diff 1 Files Affected:
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp
index a2000798a3907..74f435287af3c 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cpp
@@ -58,17 +58,16 @@ void BufferedStackTrace::UnwindFast(uptr pc, uptr bp, uptr stack_top,
// Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
while (IsValidFrame(bp, stack_top, bottom) && IsAligned(bp, sizeof(uhwptr)) &&
size < max_depth) {
- uhwptr pc1 = ((uhwptr *)bp)[15];
+ // %o7 contains the address of the call instruction and not the
+ // return address, so we need to compensate.
+ uhwptr pc1 = GetNextInstructionPc(((uhwptr *)bp)[15]);
// Let's assume that any pointer in the 0th page is invalid and
// stop unwinding here. If we're adding support for a platform
// where this isn't true, we need to reconsider this check.
if (pc1 < kPageSize)
break;
- if (pc1 != pc) {
- // %o7 contains the address of the call instruction and not the
- // return address, so we need to compensate.
- trace_buffer[size++] = GetNextInstructionPc((uptr)pc1);
- }
+ if (pc1 != pc)
+ trace_buffer[size++] = pc1;
bottom = bp;
bp = (uptr)((uhwptr *)bp)[14] + STACK_BIAS;
}
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MaskRay
approved these changes
Aug 3, 2024
```
UBSan-Standalone-sparc :: TestCases/Misc/Linux/diag-stacktrace.cpp
```
`FAIL`s on 32 and 64-bit Linux/sparc64 (and on Solaris/sparcv9, too: the
test isn't Linux-specific at all). With
`UBSAN_OPTIONS=fast_unwind_on_fatal=1`, the stack trace shows a
duplicate innermost frame:
```
compiler-rt/test/ubsan/TestCases/Misc/Linux/diag-stacktrace.cpp:14:31: runtime error: execution reached the end of a value-returning function without returning a value
#0 0x7003a708 in f() compiler-rt/test/ubsan/TestCases/Misc/Linux/diag-stacktrace.cpp:14:35
#1 0x7003a708 in f() compiler-rt/test/ubsan/TestCases/Misc/Linux/diag-stacktrace.cpp:14:35
#2 0x7003a714 in g() compiler-rt/test/ubsan/TestCases/Misc/Linux/diag-stacktrace.cpp:17:38
```
which isn't seen with `fast_unwind_on_fatal=0`.
This turns out to be another fallout from fixing
`__builtin_return_address`/`__builtin_extract_return_addr` on SPARC. In
`sanitizer_stacktrace_sparc.cpp` (`BufferedStackTrace::UnwindFast`) the
`pc` arg is the return address, while `pc1` from the stack frame
(`fr_savpc`) is the address of the `call` insn, leading to a double
entry for the innermost frame in `trace_buffer[]`.
This patch fixes this by moving the adjustment before all uses.
Tested on `sparc64-unknown-linux-gnu` and `sparcv9-sun-solaris2.11`
(with the `ubsan/TestCases/Misc/Linux` tests enabled).
(cherry picked from commit 3368a32)
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@rorth (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
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Backport 3368a32
Requested by: @rorth