maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

tsan: fix flaky test 

See the comment for explanation.

llvm-svn: 240943
This commit is contained in:
Dmitry Vyukov 2015-06-29 13:56:31 +00:00
parent 9c2f7168ca
commit 29093488d8
1 changed files with 24 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
compiler-rt/test/tsan/fd_dup_norace2.cc
View File

@ -3,6 +3,7 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
// dup2(oldfd, newfd) races with read(newfd).
// This is not reported as race because:
@ -14,14 +15,33 @@ int fd;
void *Thread(void *x) {
char buf;
if (read(fd, &buf, 1) != 1)
exit(printf("read failed\n"));
int n = read(fd, &buf, 1);
if (n != 1) {
// This read can "legitimately" fail regadless of the fact that glibc claims
// that "there is no instant in the middle of calling dup2 at which new is
// closed and not yet a duplicate of old". Strace of the failing runs
// looks as follows:
//
// [pid 122196] open("/dev/urandom", O_RDONLY) = 3
// [pid 122196] open("/dev/urandom", O_RDONLY) = 4
// Process 122382 attached
// [pid 122382] read(3, <unfinished ...>
// [pid 122196] dup2(4, 3 <unfinished ...>
// [pid 122382] <... read resumed> 0x7fcd139960b7, 1) = -1 EBADF (Bad file descriptor)
// [pid 122196] <... dup2 resumed> ) = 3
// read failed: n=-1 errno=9
//
// The failing read does not interfere with what this test tests,
// so we just ignore the failure.
//
// exit(printf("read failed: n=%d errno=%d\n", n, errno));
}
return 0;
}
int main() {
fd = open("/dev/random", O_RDONLY);
int fd2 = open("/dev/random", O_RDONLY);
fd = open("/dev/urandom", O_RDONLY);
int fd2 = open("/dev/urandom", O_RDONLY);
if (fd == -1 || fd2 == -1)
exit(printf("open failed\n"));
pthread_t th;