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 <pholzing(a)redhat.com>
---
conf.c | 8 ++++----
log.h | 4 ++--
passt.c | 8 ++++----
pasta.c | 8 ++++----
tap.c | 2 +-
util.c | 8 ++++----
vhost_user.c | 2 +-
7 files changed, 20 insertions(+), 20 deletions(-)
diff --git a/conf.c b/conf.c
index df2b016..6817377 100644
--- a/conf.c
+++ b/conf.c
@@ -769,7 +769,7 @@ static void conf_ip6_local(struct ip6_ctx *ip6)
* usage() - Print usage, exit with given status code
* @name: Executable name
* @f: Stream to print usage info to
- * @status: Status code for exit()
+ * @status: Status code for _exit()
*/
static void usage(const char *name, FILE *f, int status)
{
@@ -925,7 +925,7 @@ static void usage(const char *name, FILE *f, int status)
" SPEC is as described for TCP above\n"
" default: none\n");
- exit(status);
+ _exit(status);
pasta_opts:
@@ -980,7 +980,7 @@ pasta_opts:
" --ns-mac-addr ADDR Set MAC address on tap interface\n"
" --no-splice Disable inbound socket splicing\n");
- exit(status);
+ _exit(status);
}
/**
@@ -1482,7 +1482,7 @@ void conf(struct ctx *c, int argc, char **argv)
FPRINTF(stdout,
c->mode == MODE_PASTA ? "pasta " : "passt ");
FPRINTF(stdout, VERSION_BLOB);
- exit(EXIT_SUCCESS);
+ _exit(EXIT_SUCCESS);
case 15:
ret = snprintf(c->ip4.ifname_out,
sizeof(c->ip4.ifname_out), "%s", optarg);
diff --git a/log.h b/log.h
index a30b091..22c7b9a 100644
--- a/log.h
+++ b/log.h
@@ -32,13 +32,13 @@ void logmsg_perror(int pri, const char *format, ...)
#define die(...) \
do { \
err(__VA_ARGS__); \
- exit(EXIT_FAILURE); \
+ _exit(EXIT_FAILURE); \
} while (0)
#define die_perror(...) \
do { \
err_perror(__VA_ARGS__); \
- exit(EXIT_FAILURE); \
+ _exit(EXIT_FAILURE); \
} while (0)
extern int log_trace;
diff --git a/passt.c b/passt.c
index b1c8ab6..53fdd38 100644
--- a/passt.c
+++ b/passt.c
@@ -167,7 +167,7 @@ void exit_handler(int signal)
{
(void)signal;
- exit(EXIT_SUCCESS);
+ _exit(EXIT_SUCCESS);
}
/**
@@ -210,7 +210,7 @@ int main(int argc, char **argv)
sigaction(SIGQUIT, &sa, NULL);
if (argc < 1)
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
strncpy(argv0, argv[0], PATH_MAX - 1);
name = basename(argv0);
@@ -226,7 +226,7 @@ int main(int argc, char **argv)
} else if (strstr(name, "passt")) {
c.mode = MODE_PASST;
} else {
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
}
madvise(pkt_buf, TAP_BUF_BYTES, MADV_HUGEPAGE);
@@ -259,7 +259,7 @@ int main(int argc, char **argv)
flow_init();
if ((!c.no_udp && udp_init(&c)) || (!c.no_tcp && tcp_init(&c)))
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
proto_update_l2_buf(c.guest_mac, c.our_tap_mac);
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);
diff --git a/tap.c b/tap.c
index 772648f..8c92d23 100644
--- a/tap.c
+++ b/tap.c
@@ -1002,7 +1002,7 @@ void tap_sock_reset(struct ctx *c)
info("Client connection closed%s", c->one_off ? ", exiting" :
"");
if (c->one_off)
- exit(EXIT_SUCCESS);
+ _exit(EXIT_SUCCESS);
/* Close the connected socket, wait for a new connection */
epoll_del(c, c->fd_tap);
diff --git a/util.c b/util.c
index 800c6b5..4d51e04 100644
--- a/util.c
+++ b/util.c
@@ -405,7 +405,7 @@ void pidfile_write(int fd, pid_t pid)
if (write(fd, pid_buf, n) < 0) {
perror("PID file write");
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
}
close(fd);
@@ -441,12 +441,12 @@ int __daemon(int pidfile_fd, int devnull_fd)
if (pid == -1) {
perror("fork");
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
}
if (pid) {
pidfile_write(pidfile_fd, pid);
- exit(EXIT_SUCCESS);
+ _exit(EXIT_SUCCESS);
}
if (setsid() < 0 ||
@@ -454,7 +454,7 @@ int __daemon(int pidfile_fd, int devnull_fd)
dup2(devnull_fd, STDOUT_FILENO) < 0 ||
dup2(devnull_fd, STDERR_FILENO) < 0 ||
close(devnull_fd))
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
return 0;
}
diff --git a/vhost_user.c b/vhost_user.c
index 9e38cfd..159f0b3 100644
--- a/vhost_user.c
+++ b/vhost_user.c
@@ -60,7 +60,7 @@ void vu_print_capabilities(void)
info("{");
info(" \"type\": \"net\"");
info("}");
- exit(EXIT_SUCCESS);
+ _exit(EXIT_SUCCESS);
}
/**
--
2.48.1