From cb1bf2f321b45a06447133b3db00621b7300c456 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Mon, 2 Nov 2015 12:39:28 -0500 Subject: properly access mcontext_t program counter in cancellation handler using the actual mcontext_t definition rather than an overlaid pointer array both improves correctness/readability and eliminates some ugly hacks for archs with 64-bit registers bit 32-bit program counter. also fix UB due to comparison of pointers not in a common array object. --- src/thread/pthread_cancel.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'src/thread/pthread_cancel.c') diff --git a/src/thread/pthread_cancel.c b/src/thread/pthread_cancel.c index 0151a1ae..6eaf72c4 100644 --- a/src/thread/pthread_cancel.c +++ b/src/thread/pthread_cancel.c @@ -1,3 +1,4 @@ +#define _GNU_SOURCE #include #include "pthread_impl.h" #include "syscall.h" @@ -61,15 +62,15 @@ static void cancel_handler(int sig, siginfo_t *si, void *ctx) { pthread_t self = __pthread_self(); ucontext_t *uc = ctx; - const char *ip = ((char **)&uc->uc_mcontext)[CANCEL_REG_IP]; + uintptr_t pc = uc->uc_mcontext.MC_PC; a_barrier(); if (!self->cancel || self->canceldisable == PTHREAD_CANCEL_DISABLE) return; _sigaddset(&uc->uc_sigmask, SIGCANCEL); - if (self->cancelasync || ip >= __cp_begin && ip < __cp_end) { - ((char **)&uc->uc_mcontext)[CANCEL_REG_IP] = (char *)__cp_cancel; + if (self->cancelasync || pc >= (uintptr_t)__cp_begin && pc < (uintptr_t)__cp_end) { + uc->uc_mcontext.MC_PC = (uintptr_t)__cp_cancel; return; } -- cgit v1.2.1