From: "Darrick J. Wong" darrick.wong@oracle.com
[ Upstream commit 962cc1ad6caddb5abbb9f0a43e5abe7131a71f18 ]
In commit f2e9ad21 ("xfs: check for race with xfs_reclaim_inode"), we skip an inode if we're racing with freeing the inode via xfs_reclaim_inode, but we forgot to release the rcu read lock when dumping the inode, with the result that we exit to userspace with a lock held. Don't do that; generic/320 with a 1k block size fails this very occasionally.
================================================ WARNING: lock held when returning to user space! 4.14.0-rc6-djwong #4 Tainted: G W ------------------------------------------------ rm/30466 is leaving the kernel with locks still held! 1 lock held by rm/30466: #0: (rcu_read_lock){....}, at: [<ffffffffa01364d3>] xfs_ifree_cluster.isra.17+0x2c3/0x6f0 [xfs] ------------[ cut here ]------------ WARNING: CPU: 1 PID: 30466 at kernel/rcu/tree_plugin.h:329 rcu_note_context_switch+0x71/0x700 Modules linked in: deadline_iosched dm_snapshot dm_bufio ext4 mbcache jbd2 dm_flakey xfs libcrc32c dax_pmem device_dax nd_pmem sch_fq_codel af_packet [last unloaded: scsi_debug] CPU: 1 PID: 30466 Comm: rm Tainted: G W 4.14.0-rc6-djwong #4 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-1ubuntu1djwong0 04/01/2014 task: ffff880037680000 task.stack: ffffc90001064000 RIP: 0010:rcu_note_context_switch+0x71/0x700 RSP: 0000:ffffc90001067e50 EFLAGS: 00010002 RAX: 0000000000000001 RBX: ffff880037680000 RCX: ffff88003e73d200 RDX: 0000000000000002 RSI: ffffffff819e53e9 RDI: ffffffff819f4375 RBP: 0000000000000000 R08: 0000000000000000 R09: ffff880062c900d0 R10: 0000000000000000 R11: 0000000000000000 R12: ffff880037680000 R13: 0000000000000000 R14: ffffc90001067eb8 R15: ffff880037680690 FS: 00007fa3b8ce8700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f69bf77c000 CR3: 000000002450a000 CR4: 00000000000006e0 Call Trace: __schedule+0xb8/0xb10 schedule+0x40/0x90 exit_to_usermode_loop+0x6b/0xa0 prepare_exit_to_usermode+0x7a/0x90 retint_user+0x8/0x20 RIP: 0033:0x7fa3b87fda87 RSP: 002b:00007ffe41206568 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff02 RAX: 0000000000000000 RBX: 00000000010e88c0 RCX: 00007fa3b87fda87 RDX: 0000000000000000 RSI: 00000000010e89c8 RDI: 0000000000000005 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000000 R10: 000000000000015e R11: 0000000000000246 R12: 00000000010c8060 R13: 00007ffe41206690 R14: 0000000000000000 R15: 0000000000000000 ---[ end trace e88f83bf0cfbd07d ]---
Fixes: f2e9ad212def50bcf4c098c6288779dd97fff0f0 Cc: Omar Sandoval osandov@fb.com Signed-off-by: Darrick J. Wong darrick.wong@oracle.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Omar Sandoval osandov@fb.com Signed-off-by: Sasha Levin alexander.levin@verizon.com --- fs/xfs/xfs_inode.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 4ec5b7f45401..63350906961a 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -2378,6 +2378,7 @@ retry: */ if (ip->i_ino != inum + i) { xfs_iunlock(ip, XFS_ILOCK_EXCL); + rcu_read_unlock(); continue; } }