https://bugzilla.kernel.org/show_bug.cgi?id=219283 --- Comment #11 from Jan Kara (jack@xxxxxxx) --- I think I see the problem and AFAICT commit 0a46ef234756dca is just making the latent deadlock easier to hit. The problem is shown by these two stacktraces from your dmesg: Task 1 [ 247.045575] __wait_on_freeing_inode+0xba/0x140 [ 247.045584] find_inode_fast+0xa4/0xe0 [ 247.045588] iget_locked+0x71/0x200 [ 247.045597] __ext4_iget+0x148/0x1080 [ 247.045615] ext4_xattr_inode_cache_find+0xe2/0x220 [ 247.045621] ext4_xattr_inode_lookup_create+0x122/0x240 [ 247.045626] ext4_xattr_block_set+0xc2/0xeb0 [ 247.045633] ext4_xattr_set_handle+0x4ba/0x650 [ 247.045641] ext4_xattr_set+0x80/0x160 Task 2 [ 247.043719] mb_cache_entry_wait_unused+0x9a/0xd0 [ 247.043729] ext4_evict_ea_inode+0x64/0xb0 [ 247.043733] ext4_evict_inode+0x35c/0x6d0 [ 247.043739] evict+0x108/0x2c0 [ 247.043745] iput+0x14a/0x260 [ 247.043749] ext4_xattr_ibody_set+0x175/0x1d0 [ 247.043754] ext4_xattr_set_handle+0x297/0x650 [ 247.043762] ext4_xattr_set+0x80/0x160 These two tasks are deadlocked against each other. One has dropped the last reference to xattr inode and is trying to remove it from memory and waits for corresponding mbcache entry to get unused while another task is holding the mbcache entry reference and is waiting for inode to be evicted from memory. Commit 0a46ef234756dca removed synchronization on buffer lock for one of the hot paths and thus hitting this race is now much more likely. I just have to make up my mind how to best fix this ABBA deadlock. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
