[compiler-rt] [sanitizer_common] Don't use syscall(SYS_clone) on Linux/sparc64 (PR #100534)
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Thu Jul 25 02:00:01 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-compiler-rt-sanitizer
Author: Rainer Orth (rorth)
<details>
<summary>Changes</summary>
```
SanitizerCommon-Unit :: ./Sanitizer-sparc-Test/SanitizerCommon/StartSubprocessTest
```
and every single test using the `llvm-symbolizer` `FAIL` on Linux/sparc64 in a very weird way: when using `StartSubprocess`, there's a call to `internal_fork`, but we never reach `internal_execve`. `internal_fork` is implemented using `syscall(SYS_clone)`. The calling convention of that syscall already varies considerably between targets, but as documented in `clone(2)`, SPARC again is widely different. Instead of trying to match `glibc` here, this patch just calls `__fork`.
Tested on `sparc64-unknown-linux-gnu` and `x86_64-pc-linux-gnu`.
---
Full diff: https://github.com/llvm/llvm-project/pull/100534.diff
1 Files Affected:
- (modified) compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp (+6)
``````````diff
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
index 483a1042a6238..49f57b3404fbc 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -826,10 +826,16 @@ uptr internal_sigaltstack(const void *ss, void *oss) {
return internal_syscall(SYSCALL(sigaltstack), (uptr)ss, (uptr)oss);
}
+extern "C" pid_t __fork(void);
+
int internal_fork() {
# if SANITIZER_LINUX
# if SANITIZER_S390
return internal_syscall(SYSCALL(clone), 0, SIGCHLD);
+# elif SANITIZER_SPARC
+ // The clone syscall interface on SPARC differs massively from the rest,
+ // so fall back to __fork.
+ return __fork();
# else
return internal_syscall(SYSCALL(clone), SIGCHLD, 0);
# endif
``````````
</details>
https://github.com/llvm/llvm-project/pull/100534
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