systemd/0147-core-do-not-segfault-if-swap-activity-happens-when-p.patch
2014-01-14 19:07:25 -05:00

88 lines
2.8 KiB
Diff

From 85a77eea8d7114675602a33d2e067fd7c4ad0624 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Sun, 12 Jan 2014 11:38:56 -0500
Subject: [PATCH] core: do not segfault if swap activity happens when
/proc/swaps is not open
In https://bugzilla.redhat.com/show_bug.cgi?id=969795 systemd crashes
in swap_dispatch_reload called from manager_loop becuase m->proc_swaps
is NULL. It can legitimately be NULL if something went wrong when
initially enumerating swap devices when starting the manager. This
is probably a sign of significant trouble, but let's do our best
to recover.
---
src/core/swap.c | 45 +++++++++++++++++++++++++++++----------------
1 file changed, 29 insertions(+), 16 deletions(-)
diff --git a/src/core/swap.c b/src/core/swap.c
index 147f710..f295b65 100644
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -1068,14 +1068,40 @@ static int swap_load_proc_swaps(Manager *m, bool set_flags) {
return r;
}
+static int open_proc_swaps(Manager *m) {
+ if (!m->proc_swaps) {
+ struct epoll_event ev = {
+ .events = EPOLLPRI,
+ .data.ptr = &m->swap_watch,
+ };
+
+ m->proc_swaps = fopen("/proc/swaps", "re");
+ if (!m->proc_swaps)
+ return (errno == ENOENT) ? 0 : -errno;
+
+ m->swap_watch.type = WATCH_SWAP;
+ m->swap_watch.fd = fileno(m->proc_swaps);
+
+ if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->swap_watch.fd, &ev) < 0)
+ return -errno;
+ }
+
+ return 0;
+}
+
int swap_dispatch_reload(Manager *m) {
/* This function should go as soon as the kernel properly notifies us */
+ int r;
if (_likely_(!m->request_reload))
return 0;
m->request_reload = false;
+ r = open_proc_swaps(m);
+ if (r < 0)
+ return r;
+
return swap_fd_event(m, EPOLLPRI);
}
@@ -1225,22 +1251,9 @@ static int swap_enumerate(Manager *m) {
int r;
assert(m);
- if (!m->proc_swaps) {
- struct epoll_event ev = {
- .events = EPOLLPRI,
- .data.ptr = &m->swap_watch,
- };
-
- m->proc_swaps = fopen("/proc/swaps", "re");
- if (!m->proc_swaps)
- return (errno == ENOENT) ? 0 : -errno;
-
- m->swap_watch.type = WATCH_SWAP;
- m->swap_watch.fd = fileno(m->proc_swaps);
-
- if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->swap_watch.fd, &ev) < 0)
- return -errno;
- }
+ r = open_proc_swaps(m);
+ if (r < 0)
+ return r;
r = swap_load_proc_swaps(m, false);
if (r < 0)