From: Johannes Thumshirn johannes.thumshirn@wdc.com
commit 26ef8493e1ab771cb01d27defca2fa1315dc3980 upstream.
When running xfstests on the current btrfs I get the following splat from kmemleak:
unreferenced object 0xffff88821b2404e0 (size 32): comm "kworker/u4:7", pid 26663, jiffies 4295283698 (age 8.776s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 10 ff fd 26 82 88 ff ff ...........&.... 10 ff fd 26 82 88 ff ff 20 ff fd 26 82 88 ff ff ...&.... ..&.... backtrace: [<00000000f94fd43f>] ulist_alloc+0x25/0x60 [btrfs] [<00000000fd023d99>] btrfs_find_all_roots_safe+0x41/0x100 [btrfs] [<000000008f17bd32>] btrfs_find_all_roots+0x52/0x70 [btrfs] [<00000000b7660afb>] btrfs_qgroup_rescan_worker+0x343/0x680 [btrfs] [<0000000058e66778>] btrfs_work_helper+0xac/0x1e0 [btrfs] [<00000000f0188930>] process_one_work+0x1cf/0x350 [<00000000af5f2f8e>] worker_thread+0x28/0x3c0 [<00000000b55a1add>] kthread+0x109/0x120 [<00000000f88cbd17>] ret_from_fork+0x35/0x40
This corresponds to:
(gdb) l *(btrfs_find_all_roots_safe+0x41) 0x8d7e1 is in btrfs_find_all_roots_safe (fs/btrfs/backref.c:1413). 1408 1409 tmp = ulist_alloc(GFP_NOFS); 1410 if (!tmp) 1411 return -ENOMEM; 1412 *roots = ulist_alloc(GFP_NOFS); 1413 if (!*roots) { 1414 ulist_free(tmp); 1415 return -ENOMEM; 1416 } 1417
Following the lifetime of the allocated 'roots' ulist, it gets freed again in btrfs_qgroup_account_extent().
But this does not happen if the function is called with the 'BTRFS_FS_QUOTA_ENABLED' flag cleared, then btrfs_qgroup_account_extent() does a short leave and directly returns.
Instead of directly returning we should jump to the 'out_free' in order to free all resources as expected.
CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Qu Wenruo wqu@suse.com Signed-off-by: Johannes Thumshirn johannes.thumshirn@wdc.com [ add comment ] Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/btrfs/qgroup.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1928,8 +1928,12 @@ btrfs_qgroup_account_extent(struct btrfs u64 nr_old_roots = 0; int ret = 0;
+ /* + * If quotas get disabled meanwhile, the resouces need to be freed and + * we can't just exit here. + */ if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) - return 0; + goto out_free;
if (new_roots) { if (!maybe_fs_roots(new_roots))