From: Naohiro Aota naohiro.aota@wdc.com
commit 784daf2b9628f2d0117f1f0b578cfe5ab6634919 upstream.
The fstests test case generic/475 creates a dm-linear device that gets changed to a dm-error device. This leads to errors in loading the block group's zone information when running on a zoned file system, ultimately resulting in a list corruption. When running on a kernel with list debugging enabled this leads to the following crash.
BTRFS: error (device dm-2) in cleanup_transaction:1953: errno=-5 IO failure kernel BUG at lib/list_debug.c:54! invalid opcode: 0000 [#1] SMP PTI CPU: 1 PID: 2433 Comm: umount Tainted: G W 5.12.0+ #1018 RIP: 0010:__list_del_entry_valid.cold+0x1d/0x47 RSP: 0018:ffffc90001473df0 EFLAGS: 00010296 RAX: 0000000000000054 RBX: ffff8881038fd000 RCX: ffffc90001473c90 RDX: 0000000100001a31 RSI: 0000000000000003 RDI: 0000000000000003 RBP: ffff888308871108 R08: 0000000000000003 R09: 0000000000000001 R10: 3961373532383838 R11: 6666666620736177 R12: ffff888308871000 R13: ffff8881038fd088 R14: ffff8881038fdc78 R15: dead000000000100 FS: 00007f353c9b1540(0000) GS:ffff888627d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f353cc2c710 CR3: 000000018e13c000 CR4: 00000000000006a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: btrfs_free_block_groups+0xc9/0x310 [btrfs] close_ctree+0x2ee/0x31a [btrfs] ? call_rcu+0x8f/0x270 ? mutex_lock+0x1c/0x40 generic_shutdown_super+0x67/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x90 cleanup_mnt+0x13e/0x1b0 task_work_run+0x63/0xb0 exit_to_user_mode_loop+0xd9/0xe0 exit_to_user_mode_prepare+0x3e/0x60 syscall_exit_to_user_mode+0x1d/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xae
As dm-error has no support for zones, btrfs will run it's zone emulation mode on this device. The zone emulation mode emulates conventional zones, so bail out if the zone bitmap that gets populated on mount sees the zone as sequential while we're thinking it's a conventional zone when creating a block group.
Note: this scenario is unlikely in a real wold application and can only happen by this (ab)use of device-mapper targets.
CC: stable@vger.kernel.org # 5.12+ Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Signed-off-by: Johannes Thumshirn johannes.thumshirn@wdc.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/zoned.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/fs/btrfs/zoned.c +++ b/fs/btrfs/zoned.c @@ -1126,6 +1126,11 @@ int btrfs_load_block_group_zone_info(str goto out; }
+ if (zone.type == BLK_ZONE_TYPE_CONVENTIONAL) { + ret = -EIO; + goto out; + } + switch (zone.cond) { case BLK_ZONE_COND_OFFLINE: case BLK_ZONE_COND_READONLY: