From d0006fa784a7de881db187756770d2492c75df5d Mon Sep 17 00:00:00 2001 From: Paul Holzinger Date: Wed, 5 Feb 2025 14:00:41 +0100 Subject: treewide: use _exit() over exit() In the podman CI I noticed many seccomp denials in our logs even though tests passed: comm="pasta.avx2" exe="/usr/bin/pasta.avx2" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7fb3d31f69db code=0x80000000 Which is futex being called and blocked by the pasta profile. After a few tries I managed to reproduce locally with this loop in ~20 min: while :; do podman run -d --network bridge quay.io/libpod/testimage:20241011 \ sleep 100 && \ sleep 10 && \ podman rm -fa -t0 done And using a pasta version with prctl(PR_SET_DUMPABLE, 1); set I got the following stack trace: Stack trace of thread 1: #0 0x00007fc95e6de91b __lll_lock_wait_private (libc.so.6 + 0x9491b) #1 0x00007fc95e68d6de __run_exit_handlers (libc.so.6 + 0x436de) #2 0x00007fc95e68d70e exit (libc.so.6 + 0x4370e) #3 0x000055f31b78c50b n/a (n/a + 0x0) #4 0x00007fc95e68d70e exit (libc.so.6 + 0x4370e) #5 0x000055f31b78d5a2 n/a (n/a + 0x0) Pasta got killed in exit(), it seems glibc is trying to use a lock when running exit handlers even though no exit handlers are defined. Given no exit handlers are needed we can call _exit() instead. This skips exit handlers and does not flush stdio streams compared to exit() which should be fine for the use here. Based on the input from Stefano I did not change the test/doc programs or qrap as they do not use seccomp filters. Signed-off-by: Paul Holzinger Signed-off-by: Stefano Brivio --- pasta.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'pasta.c') diff --git a/pasta.c b/pasta.c index ff41c95..f15084d 100644 --- a/pasta.c +++ b/pasta.c @@ -73,12 +73,12 @@ void pasta_child_handler(int signal) !waitid(P_PID, pasta_child_pid, &infop, WEXITED | WNOHANG)) { if (infop.si_pid == pasta_child_pid) { if (infop.si_code == CLD_EXITED) - exit(infop.si_status); + _exit(infop.si_status); /* If killed by a signal, si_status is the number. * Follow common shell convention of returning it + 128. */ - exit(infop.si_status + 128); + _exit(infop.si_status + 128); /* Nothing to do, detached PID namespace going away */ } @@ -499,7 +499,7 @@ void pasta_netns_quit_inotify_handler(struct ctx *c, int inotify_fd) return; info("Namespace %s is gone, exiting", c->netns_base); - exit(EXIT_SUCCESS); + _exit(EXIT_SUCCESS); } /** @@ -525,7 +525,7 @@ void pasta_netns_quit_timer_handler(struct ctx *c, union epoll_ref ref) return; info("Namespace %s is gone, exiting", c->netns_base); - exit(EXIT_SUCCESS); + _exit(EXIT_SUCCESS); } close(fd); -- cgit v1.2.3