On Fri, Feb 09, 2024 at 12:21:00PM +0100, Jan Kara wrote: > ext4_xattr_set_entry() creates new EA inodes while holding buffer lock > on the external xattr block. This is problematic as it nests all the > allocation locking (which acquires locks on other buffers) under the > buffer lock. This can even deadlock when the filesystem is corrupted and > e.g. quota file is setup to contain xattr block as data block. Move the > allocation of EA inode out of ext4_xattr_set_entry() into the callers. > > Reported-by: syzbot+a43d4f48b8397d0e41a9@xxxxxxxxxxxxxxxxxxxxxxxxx > Signed-off-by: Jan Kara <jack@xxxxxxx> In my testing I've found that this is causing a regression for ext4/026 in the encrypt configuration. This can be replicated using "kvm-xfstests -c encrypt ext4/026. Logs follow below. I'll try to take a closer look, but I may end up deciding to drop this patch or possible the whole patch series until we can figure out what's going on. - Ted ext4/026 1s ... [10:51:57][ 3.111475] run fstests ext4/026 at 2024-02-29 10:51:57 EXT4-fs (vdc): Test dummy encryption mode enabled EXT4-fs (vdc): Test dummy encryption mode enabled EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 ------------[ cut here ]------------ EA inode 18 ref_count=-1 WARNING: CPU: 0 PID: 2391 at fs/ext4/xattr.c:1064 ext4_xattr_inode_update_ref+0x1c0/0x230 CPU: 0 PID: 2391 Comm: setfattr Not tainted 6.8.0-rc3-xfstests-00021-gf7528aea5d49 #320 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:ext4_xattr_inode_update_ref+0x1c0/0x230 Code: 0b e9 21 ff ff ff 80 3d 13 47 5a 01 00 0f 85 14 ff ff ff 48 8b 73 40 48 c7 c7 a6 8e 5d 82 c6 05 fb 46 5a 01 01 e8 50 40 c1 ff <0f> 0b e9 f6 fe ff ff 80 3d e7 46 5a 01 00 0f 85 5d ff ff ff 48 8b RSP: 0018:ffffc900032cb980 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8880043438a8 RCX: 0000000000000027 RDX: ffff88807dc1c848 RSI: 0000000000000001 RDI: ffff88807dc1c840 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff82860e00 R10: ffffc900032cb828 R11: ffffffff828d0e48 R12: ffff888007c93150 R13: ffff888004343948 R14: 00000000ffffffff R15: ffff8880043438a8 FS: 00007fab1e02b740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055e0e4fd2000 CR3: 000000000a0a6002 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: <TASK> ? ext4_xattr_inode_update_ref+0x1c0/0x230 ? __warn+0x7c/0x130 ? ext4_xattr_inode_update_ref+0x1c0/0x230 ? report_bug+0x173/0x1d0 ? handle_bug+0x3a/0x70 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? ext4_xattr_inode_update_ref+0x1c0/0x230 ext4_xattr_inode_dec_ref_all+0x166/0x330 ext4_xattr_release_block+0x29e/0x300 ext4_xattr_block_set+0x795/0xc70 ext4_xattr_set_handle+0x468/0x680 ext4_xattr_set+0x88/0x160 __vfs_setxattr+0x96/0xd0 __vfs_setxattr_noperm+0x79/0x1d0 vfs_setxattr+0x9f/0x180 setxattr+0x9e/0xc0 path_setxattr+0xc9/0xf0 __x64_sys_setxattr+0x2b/0x40 do_syscall_64+0x52/0x120 entry_SYSCALL_64_after_hwframe+0x6e/0x76 RIP: 0033:0x7fab1e12f4f9 Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d d7 08 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007fffe7694618 EFLAGS: 00000206 ORIG_RAX: 00000000000000bc RAX: ffffffffffffffda RBX: 000055e0e4fc3340 RCX: 00007fab1e12f4f9 RDX: 000055e0e4fc3340 RSI: 00007fffe7695a22 RDI: 00007fffe76a5a96 RBP: 00007fffe76a5a96 R08: 0000000000000000 R09: 00007fab1e247020 R10: 0000000000010000 R11: 0000000000000206 R12: 00007fffe7695a22 R13: 000055e0e3e8008c R14: 000055e0e3e82100 R15: 00007fab1e247020 </TASK> ---[ end trace 0000000000000000 ]--- EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs error (device vdc): ext4_xattr_inode_iget:443: comm getfattr: error while reading EA inode 18 err=-116 EXT4-fs (vdc): Test dummy encryption mode enabled EXT4-fs (vdc): warning: mounting fs with errors, running e2fsck is recommended
