From: Yang Xu xuyang2018.jy@fujitsu.com
commit a1de97fe296c52eafc6590a3506f4bbd44ecb19a upstream.
When testing xfstests xfs/126 on lastest upstream kernel, it will hang on some machine. Adding a getxattr operation after xattr corrupted, I can reproduce it 100%.
The deadlock as below: [983.923403] task:setfattr state:D stack: 0 pid:17639 ppid: 14687 flags:0x00000080 [ 983.923405] Call Trace: [ 983.923410] __schedule+0x2c4/0x700 [ 983.923412] schedule+0x37/0xa0 [ 983.923414] schedule_timeout+0x274/0x300 [ 983.923416] __down+0x9b/0xf0 [ 983.923451] ? xfs_buf_find.isra.29+0x3c8/0x5f0 [xfs] [ 983.923453] down+0x3b/0x50 [ 983.923471] xfs_buf_lock+0x33/0xf0 [xfs] [ 983.923490] xfs_buf_find.isra.29+0x3c8/0x5f0 [xfs] [ 983.923508] xfs_buf_get_map+0x4c/0x320 [xfs] [ 983.923525] xfs_buf_read_map+0x53/0x310 [xfs] [ 983.923541] ? xfs_da_read_buf+0xcf/0x120 [xfs] [ 983.923560] xfs_trans_read_buf_map+0x1cf/0x360 [xfs] [ 983.923575] ? xfs_da_read_buf+0xcf/0x120 [xfs] [ 983.923590] xfs_da_read_buf+0xcf/0x120 [xfs] [ 983.923606] xfs_da3_node_read+0x1f/0x40 [xfs] [ 983.923621] xfs_da3_node_lookup_int+0x69/0x4a0 [xfs] [ 983.923624] ? kmem_cache_alloc+0x12e/0x270 [ 983.923637] xfs_attr_node_hasname+0x6e/0xa0 [xfs] [ 983.923651] xfs_has_attr+0x6e/0xd0 [xfs] [ 983.923664] xfs_attr_set+0x273/0x320 [xfs] [ 983.923683] xfs_xattr_set+0x87/0xd0 [xfs] [ 983.923686] __vfs_removexattr+0x4d/0x60 [ 983.923688] __vfs_removexattr_locked+0xac/0x130 [ 983.923689] vfs_removexattr+0x4e/0xf0 [ 983.923690] removexattr+0x4d/0x80 [ 983.923693] ? __check_object_size+0xa8/0x16b [ 983.923695] ? strncpy_from_user+0x47/0x1a0 [ 983.923696] ? getname_flags+0x6a/0x1e0 [ 983.923697] ? _cond_resched+0x15/0x30 [ 983.923699] ? __sb_start_write+0x1e/0x70 [ 983.923700] ? mnt_want_write+0x28/0x50 [ 983.923701] path_removexattr+0x9b/0xb0 [ 983.923702] __x64_sys_removexattr+0x17/0x20 [ 983.923704] do_syscall_64+0x5b/0x1a0 [ 983.923705] entry_SYSCALL_64_after_hwframe+0x65/0xca [ 983.923707] RIP: 0033:0x7f080f10ee1b
When getxattr calls xfs_attr_node_get function, xfs_da3_node_lookup_int fails with EFSCORRUPTED in xfs_attr_node_hasname because we have use blocktrash to random it in xfs/126. So it free state in internal and xfs_attr_node_get doesn't do xfs_buf_trans release job.
Then subsequent removexattr will hang because of it.
This bug was introduced by kernel commit 07120f1abdff ("xfs: Add xfs_has_attr and subroutines"). It adds xfs_attr_node_hasname helper and said caller will be responsible for freeing the state in this case. But xfs_attr_node_hasname will free state itself instead of caller if xfs_da3_node_lookup_int fails.
Fix this bug by moving the step of free state into caller.
[amir: this text from original commit is not relevant for 5.10 backport: Also, use "goto error/out" instead of returning error directly in xfs_attr_node_addname_find_attr and xfs_attr_node_removename_setup function because we should free state ourselves. ]
Fixes: 07120f1abdff ("xfs: Add xfs_has_attr and subroutines") Signed-off-by: Yang Xu xuyang2018.jy@fujitsu.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/libxfs/xfs_attr.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c index 96ac7e562b87..fcca36bbd997 100644 --- a/fs/xfs/libxfs/xfs_attr.c +++ b/fs/xfs/libxfs/xfs_attr.c @@ -876,21 +876,18 @@ xfs_attr_node_hasname(
state = xfs_da_state_alloc(args); if (statep != NULL) - *statep = NULL; + *statep = state;
/* * Search to see if name exists, and get back a pointer to it. */ error = xfs_da3_node_lookup_int(state, &retval); - if (error) { - xfs_da_state_free(state); - return error; - } + if (error) + retval = error;
- if (statep != NULL) - *statep = state; - else + if (!statep) xfs_da_state_free(state); + return retval; }