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authorDmitri Monakhov <dmonakhov@openvz.org>2008-12-09 13:14:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-12-10 08:01:53 -0800
commit6ee5a399d6a92a52646836a6e10faf255c16393e (patch)
tree52966233a5093c0d7cdeb244be9b6c3c8e1760c4 /fs
parentaa6f14796630c8b03c11e782484aec2aee05e671 (diff)
downloadconfigs-6ee5a399d6a92a52646836a6e10faf255c16393e.tar.gz
inotify: fix IN_ONESHOT unmount event watcher
On umount two event will be dispatched to watcher: 1: inotify_dev_queue_event(.., IN_UNMOUNT,..) 2: remove_watch(watch, dev) ->inotify_dev_queue_event(.., IN_IGNORED, ..) But if watcher has IN_ONESHOT bit set then the watcher will be released inside first event. Which result in accessing invalid object later. IMHO it is not pure regression. This bug wasn't triggered while initial inotify interface testing phase because of another bug in IN_ONESHOT handling logic :) commit ac74c00e499ed276a965e5b5600667d5dc04a84a Author: Ulisses Furquim <ulissesf@gmail.com> Date: Fri Feb 8 04:18:16 2008 -0800 inotify: fix check for one-shot watches before destroying them As the IN_ONESHOT bit is never set when an event is sent we must check it in the watch's mask and not in the event's mask. TESTCASE: mkdir mnt mount -ttmpfs none mnt mkdir mnt/d ./inotify mnt/d& umount mnt ## << lockup or crash here TESTSOURCE: /* gcc -oinotify inotify.c */ #include <stdio.h> #include <stdlib.h> #include <sys/inotify.h> int main(int argc, char **argv) { char buf[1024]; struct inotify_event *ie; char *p; int i; ssize_t l; p = argv[1]; i = inotify_init(); inotify_add_watch(i, p, ~0); l = read(i, buf, sizeof(buf)); printf("read %d bytes\n", l); ie = (struct inotify_event *) buf; printf("event mask: %d\n", ie->mask); return 0; } Signed-off-by: Dmitri Monakhov <dmonakhov@openvz.org> Cc: John McCutchan <ttb@tentacle.dhs.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Robert Love <rlove@google.com> Cc: Ulisses Furquim <ulissesf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/inotify.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/inotify.c b/fs/inotify.c
index 7bbed1b8982..dae3f28f30d 100644
--- a/fs/inotify.c
+++ b/fs/inotify.c
@@ -428,11 +428,13 @@ void inotify_unmount_inodes(struct list_head *list)
watches = &inode->inotify_watches;
list_for_each_entry_safe(watch, next_w, watches, i_list) {
struct inotify_handle *ih= watch->ih;
+ get_inotify_watch(watch);
mutex_lock(&ih->mutex);
ih->in_ops->handle_event(watch, watch->wd, IN_UNMOUNT, 0,
NULL, NULL);
inotify_remove_watch_locked(ih, watch);
mutex_unlock(&ih->mutex);
+ put_inotify_watch(watch);
}
mutex_unlock(&inode->inotify_mutex);
iput(inode);