| From | Greg Kroah-Hartman <> | Subject | [ 100/123] fs: Fix imbalance in freeze protection in mark_files_ro() | Date | Wed, 9 Jan 2013 12:35:39 -0800 |
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3.7-stable review patch. If anyone has any objections, please let me know.
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From: Jan Kara <jack@suse.cz>
commit 72651cac884b1e285fa8e8314b10e9f1b8458802 upstream.
File descriptors (even those for writing) do not hold freeze protection. Thus mark_files_ro() must call __mnt_drop_write() to only drop protection against remount read-only. Calling mnt_drop_write_file() as we do now results in:
[ BUG: bad unlock balance detected! ] 3.7.0-rc6-00028-g88e75b6 #101 Not tainted ------------------------------------- kworker/1:2/79 is trying to release lock (sb_writers) at: [<ffffffff811b33b4>] mnt_drop_write+0x24/0x30 but there are no more locks to release!
Reported-by: Zdenek Kabelac <zkabelac@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/file_table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/file_table.c +++ b/fs/file_table.c @@ -458,8 +458,8 @@ void mark_files_ro(struct super_block *s spin_unlock(&f->f_lock); if (file_check_writeable(f) != 0) continue; + __mnt_drop_write(f->f_path.mnt); file_release_write(f); - mnt_drop_write_file(f); } while_file_list_for_each_entry; lg_global_unlock(&files_lglock); }
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