_thr_sig_check_pending is also called by scope system thread when it leaves

critical region, we wrap some syscalls for thread cancellation point, and
when syscalls returns, we call _thr_leave_cancellation_point, at the time
if a signal comes in, it would be buffered, and when the thread leaves
_thr_leave_cancellation_point, buffered signals will be processed, to avoid
messing up normal syscall errno, we should save and restore errno around
signal handling code.

2 files changed, 6 insertions, 0 deletions

diff --git a/lib/libkse/thread/thr_sig.c b/lib/libkse/thread/thr_sig.c
index 01b0914..26c1317 100644
--- a/lib/libkse/thread/thr_sig.c
+++ b/lib/libkse/thread/thr_sig.c
@@ -750,10 +750,12 @@ _thr_sig_check_pending(struct pthread *curthread)
 {
 	ucontext_t uc;
 	volatile int once;
+	int errsave;
 
 	if (THR_IN_CRITICAL(curthread))
 		return;
 
+	errsave = errno;
 	once = 0;
 	THR_GETCONTEXT(&uc);
 	if (once == 0) {
@@ -761,6 +763,7 @@ _thr_sig_check_pending(struct pthread *curthread)
 		curthread->check_pending = 0;
 		_thr_sig_rundown(curthread, &uc, NULL);
 	}
+	errno = errsave;
 }
 
 #ifndef SYSTEM_SCOPE_ONLY
diff --git a/lib/libpthread/thread/thr_sig.c b/lib/libpthread/thread/thr_sig.c
index 01b0914..26c1317 100644
--- a/lib/libpthread/thread/thr_sig.c
+++ b/lib/libpthread/thread/thr_sig.c
@@ -750,10 +750,12 @@ _thr_sig_check_pending(struct pthread *curthread)
 {
 	ucontext_t uc;
 	volatile int once;
+	int errsave;
 
 	if (THR_IN_CRITICAL(curthread))
 		return;
 
+	errsave = errno;
 	once = 0;
 	THR_GETCONTEXT(&uc);
 	if (once == 0) {
@@ -761,6 +763,7 @@ _thr_sig_check_pending(struct pthread *curthread)
 		curthread->check_pending = 0;
 		_thr_sig_rundown(curthread, &uc, NULL);
 	}
+	errno = errsave;
 }
 
 #ifndef SYSTEM_SCOPE_ONLY