inotify will WARN() if it finds that the idr and the fsnotify internals
somehow got out of sync. It was only supposed to do this once but due
to this stupid bug it would warn every single time a problem was
detected.
Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If an inotify watch is left in the idr when an fsnotify group is destroyed
this will lead to a BUG. This is not a dangerous situation and really
indicates a programming bug and leak of memory. This patch changes it to
use a WARN and a printk rather than killing people's boxes.
Signed-off-by: Eric Paris <eparis@redhat.com>
inotify decides if private data it passed to get added to an event was
used by checking list_empty(). But it's possible that the event may
have been dequeued and the private event removed so it would look empty.
The fix is to use the return code from fsnotify_add_notify_event rather
than looking at the list.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
inotify_destroy_mark_entry could get called twice for the same mark since it
is called directly in inotify_rm_watch and when the mark is being destroyed for
another reason. As an example assume that the file being watched was just
deleted so inotify_destroy_mark_entry would get called from the path
fsnotify_inoderemove() -> fsnotify_destroy_marks_by_inode() ->
fsnotify_destroy_mark_entry() -> inotify_destroy_mark_entry(). If this
happened at the same time as userspace tried to remove a watch via
inotify_rm_watch we could attempt to remove the mark from the idr twice and
could thus double dec the ref cnt and potentially could be in a use after
free/double free situation. The fix is to have inotify_rm_watch use the
generic recursive safe fsnotify_destroy_mark_by_entry() so we are sure the
inotify_destroy_mark_entry() function can only be called one.
This patch also renames the function to inotify_ingored_remove_idr() so it is
clear what is actually going on in the function.
Hopefully this fixes:
[ 20.342058] idr_remove called for id=20 which is not allocated.
[ 20.348000] Pid: 1860, comm: udevd Not tainted 2.6.30-tip #1077
[ 20.353933] Call Trace:
[ 20.356410] [<ffffffff811a82b7>] idr_remove+0x115/0x18f
[ 20.361737] [<ffffffff8134259d>] ? _spin_lock+0x6d/0x75
[ 20.367061] [<ffffffff8111640a>] ? inotify_destroy_mark_entry+0xa3/0xcf
[ 20.373771] [<ffffffff8111641e>] inotify_destroy_mark_entry+0xb7/0xcf
[ 20.380306] [<ffffffff81115913>] inotify_freeing_mark+0xe/0x10
[ 20.386238] [<ffffffff8111410d>] fsnotify_destroy_mark_by_entry+0x143/0x170
[ 20.393293] [<ffffffff811163a3>] inotify_destroy_mark_entry+0x3c/0xcf
[ 20.399829] [<ffffffff811164d1>] sys_inotify_rm_watch+0x9b/0xc6
[ 20.405850] [<ffffffff8100bcdb>] system_call_fastpath+0x16/0x1b
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Eric Paris <eparis@redhat.com>
Tested-by: Peter Ziljlstra <peterz@infradead.org>
inotify and dnotify will both indicate that they want any event which came
from a child inode. The fix is to mask off FS_EVENT_ON_CHILD when deciding
if inotify or dnotify is interested in a given event.
Signed-off-by: Eric Paris <eparis@redhat.com>
Reimplement inotify_user using fsnotify. This should be feature for feature
exactly the same as the original inotify_user. This does not make any changes
to the in kernel inotify feature used by audit. Those patches (and the eventual
removal of in kernel inotify) will come after the new inotify_user proves to be
working correctly.
Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Eric Paris