[ASAN] Turn off asan instrumentation in segv handler (JuliaLang#46377)

There's some issues around asan and segv handlers. The issues I'm aware of is: 1. If things run on the sigaltstack, we need to at some point unpoison the sigaltstack and it's not clear when to do that. 2. Sanitizers accidentally free stil-in-use stack frames: google/sanitizers#1561 3. If noreturn functions run on the sigaltstack, asan can get confused about what it needs to unpoison So for now, remove asan instrumentation from the segv_handler and the the jl_call_in_ctx functions (jl_sig_throw is already annotated). This helps the case I was seeing (where gc_srub would cause frequent segv_handler invocations for safe restore), but there's probably a few other landmines remaining here.
green-nsk · Aug 17, 2022 · 4af9674 · 4af9674
1 parent 0ada892
commit 4af9674
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/src/signals-unix.c b/src/signals-unix.c
@@ -104,7 +104,7 @@ static int is_addr_on_sigstack(jl_ptls_t ptls, void *ptr)
 // returns. `fptr` will execute on the signal stack, and must not return.
 // jl_call_in_ctx is also currently executing on that signal stack,
 // so be careful not to smash it
-static void jl_call_in_ctx(jl_ptls_t ptls, void (*fptr)(void), int sig, void *_ctx)
+JL_NO_ASAN static void jl_call_in_ctx(jl_ptls_t ptls, void (*fptr)(void), int sig, void *_ctx)
 {
     // Modifying the ucontext should work but there is concern that
     // sigreturn oriented programming mitigation can work against us
@@ -310,7 +310,7 @@ static int jl_is_on_sigstack(jl_ptls_t ptls, void *ptr, void *context)
             is_addr_on_sigstack(ptls, (void*)jl_get_rsp_from_ctx(context)));
 }
 
-static void segv_handler(int sig, siginfo_t *info, void *context)
+JL_NO_ASAN static void segv_handler(int sig, siginfo_t *info, void *context)
 {
     if (jl_get_safe_restore()) { // restarting jl_ or profile
         jl_call_in_ctx(NULL, &jl_sig_throw, sig, context);