From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Various C library implementations have various races with regards
to caching getpid() or TID inside pthread_kill() implementations.
For example see clone(2) glibc man page and pthread_kill
Bionic C library source.
Work around that by making sure correct PID/TGID and TID values
are retrieved from the kernel when re-raising the signal. It
can be delivered immediately after the clone system call while C
library cached copies have not yet been updated.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
lib/drmtest.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/lib/drmtest.c b/lib/drmtest.c
index dcacd3b..139eb82 100644
--- a/lib/drmtest.c
+++ b/lib/drmtest.c
@@ -43,6 +43,8 @@
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/syscall.h>
#include "drmtest.h"
#include "i915_drm.h"
@@ -1473,6 +1475,8 @@ static void igt_atexit_handler(void)
static void fatal_sig_handler(int sig)
{
+ pid_t pid, tid;
+
restore_all_sig_handler();
/*
@@ -1481,7 +1485,11 @@ static void fatal_sig_handler(int sig)
*/
call_exit_handlers(sig);
- raise(sig);
+ /* Workaround cached PID and TID races on glibc and Bionic libc. */
+ pid = syscall(SYS_getpid);
+ tid = syscall(SYS_gettid);
+
+ syscall(SYS_tgkill, pid, tid, sig);
}
/*
--
1.8.4.3
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