| Message ID | 1400269921-17141-1-git-send-email-fdmanana@gmail.com (mailing list archive) |
|---|---|
| State | Deferred |
| Headers | show |
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index eb0760f..0bad610 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -6456,6 +6456,8 @@ static noinline int find_free_extent(struct btrfs_root *orig_root, } else { index = get_block_group_index(block_group); btrfs_grab_block_group(block_group, delalloc); + /* compensate get by btrfs_grab_block_group() */ + btrfs_put_block_group(block_group); goto have_block_group; } } else if (block_group) {
The change titled: "Btrfs: fix broken free space cache after the system crashed" can increment a block group cache object twice in find_free_extent() and never decrement it twice, resulting in a memory leak. This is easy to reproduce by having kmemleak enabled and the following steps: mkfs.btrfs -f /dev/sdd mount /dev/sdd /mnt umount /mnt rmmod btrfs cat /sys/kernel/debug/kmemleak unreferenced object 0xffff8802089249d8 (size 512): comm "mount", pid 6826, jiffies 4306001111 (age 3065.636s) hex dump (first 32 bytes): 00 00 c0 01 00 00 00 00 c0 00 00 00 40 00 00 00 ............@... 00 00 c0 01 00 00 00 00 00 00 01 00 00 00 00 00 ................ backtrace: [<ffffffff816ab3b6>] kmemleak_alloc+0x26/0x50 [<ffffffff8119447d>] kmem_cache_alloc_trace+0x11d/0x1e0 [<ffffffffa02a369c>] btrfs_create_block_group_cache+0x3c/0x160 [btrfs] [<ffffffffa02adf07>] btrfs_read_block_groups+0x1d7/0x650 [btrfs] [<ffffffffa02bc800>] open_ctree+0x16a0/0x20c0 [btrfs] [<ffffffffa0293321>] btrfs_mount+0x6b1/0x980 [btrfs] [<ffffffff811aa9c0>] mount_fs+0x20/0xe0 [<ffffffff811c76f3>] vfs_kern_mount+0x73/0x170 [<ffffffff811ca046>] do_mount+0x206/0xb20 [<ffffffff811cac4e>] SyS_mount+0x8e/0xe0 [<ffffffff816c8492>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff unreferenced object 0xffff8802019571d0 (size 128): comm "mount", pid 6826, jiffies 4306001111 (age 3065.684s) hex dump (first 32 bytes): 4d 06 4d 06 ad 4e ad de ff ff ff ff 00 00 00 00 M.M..N.......... ff ff ff ff ff ff ff ff 90 0d 36 a0 ff ff ff ff ..........6..... backtrace: [<ffffffff816ab3b6>] kmemleak_alloc+0x26/0x50 [<ffffffff8119447d>] kmem_cache_alloc_trace+0x11d/0x1e0 [<ffffffffa02a36be>] btrfs_create_block_group_cache+0x5e/0x160 [btrfs] [<ffffffffa02adf07>] btrfs_read_block_groups+0x1d7/0x650 [btrfs] [<ffffffffa02bc800>] open_ctree+0x16a0/0x20c0 [btrfs] [<ffffffffa0293321>] btrfs_mount+0x6b1/0x980 [btrfs] [<ffffffff811aa9c0>] mount_fs+0x20/0xe0 [<ffffffff811c76f3>] vfs_kern_mount+0x73/0x170 [<ffffffff811ca046>] do_mount+0x206/0xb20 [<ffffffff811cac4e>] SyS_mount+0x8e/0xe0 [<ffffffff816c8492>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> --- Note: this only affects Chris' integration branch. fs/btrfs/extent-tree.c | 2 ++ 1 file changed, 2 insertions(+)