syzbot

loop0: detected capacity change from 0 to 512
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.17/4315 is trying to acquire lock:
ffff8880771cebd8 (&sbi->s_writepages_rwsem){.+.+}-{0:0}, at: ext4_writepages+0x20f/0x2df0 fs/ext4/inode.c:2689

but task is already holding lock:
ffff8880602f0ac0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
ffff8880602f0ac0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5941 [inline]
ffff8880602f0ac0 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x3e8/0x700 fs/ext4/inode.c:6022

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&ei->xattr_sem){++++}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ext4_setattr+0x71d/0x19e0 fs/ext4/inode.c:5465
       notify_change+0xbcd/0xee0 fs/attr.c:505
       chown_common+0x4a7/0x660 fs/open.c:680
       do_fchownat+0x147/0x240 fs/open.c:711
       __do_sys_chown fs/open.c:731 [inline]
       __se_sys_chown fs/open.c:729 [inline]
       __x64_sys_chown+0x7e/0x90 fs/open.c:729
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (jbd2_handle){++++}-{0:0}:
       start_this_handle+0x136f/0x15c0 fs/jbd2/transaction.c:464
       jbd2__journal_start+0x2b7/0x5a0 fs/jbd2/transaction.c:521
       __ext4_journal_start_sb+0x167/0x360 fs/ext4/ext4_jbd2.c:105
       __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
       ext4_writepages+0xe53/0x2df0 fs/ext4/inode.c:2812
       do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
       filemap_fdatawrite_wbc+0x1eb/0x240 mm/filemap.c:400
       __filemap_fdatawrite_range mm/filemap.c:433 [inline]
       file_write_and_wait_range+0x14d/0x220 mm/filemap.c:810
       ext4_sync_file+0x1ff/0xae0 fs/ext4/fsync.c:151
       vfs_fsync_range fs/sync.c:188 [inline]
       vfs_fsync fs/sync.c:202 [inline]
       do_fsync fs/sync.c:212 [inline]
       __do_sys_fsync fs/sync.c:220 [inline]
       __se_sys_fsync fs/sync.c:218 [inline]
       __x64_sys_fsync+0x1a5/0x1e0 fs/sync.c:218
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&sbi->s_writepages_rwsem){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
       lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
       percpu_down_read+0x46/0x1b0 include/linux/percpu-rwsem.h:51
       ext4_writepages+0x20f/0x2df0 fs/ext4/inode.c:2689
       do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
       __writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
       writeback_single_inode+0x3cb/0x8e0 fs/fs-writeback.c:1770
       write_inode_now+0x23b/0x2c0 fs/fs-writeback.c:2811
       iput_final fs/inode.c:1756 [inline]
       iput+0x5ab/0x8a0 fs/inode.c:1795
       ext4_xattr_set_entry+0x34f4/0x3ea0 fs/ext4/xattr.c:1837
       ext4_xattr_block_set+0x4fd/0x2d20 fs/ext4/xattr.c:1936
       ext4_xattr_move_to_block fs/ext4/xattr.c:2633 [inline]
       ext4_xattr_make_inode_space fs/ext4/xattr.c:2708 [inline]
       ext4_expand_extra_isize_ea+0xf3b/0x1990 fs/ext4/xattr.c:2800
       __ext4_expand_extra_isize+0x301/0x3e0 fs/ext4/inode.c:5901
       ext4_try_to_expand_extra_isize fs/ext4/inode.c:5944 [inline]
       __ext4_mark_inode_dirty+0x469/0x700 fs/ext4/inode.c:6022
       ext4_evict_inode+0xa8d/0x1090 fs/ext4/inode.c:282
       evict+0x4c9/0x8d0 fs/inode.c:647
       ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:470
       ext4_fill_super+0x92c9/0x9a40 fs/ext4/super.c:4975
       mount_bdev+0x287/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x24a/0xa40 fs/namespace.c:3034
       do_mount fs/namespace.c:3377 [inline]
       __do_sys_mount fs/namespace.c:3585 [inline]
       __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
  &sbi->s_writepages_rwsem --> jbd2_handle --> &ei->xattr_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->xattr_sem);
                               lock(jbd2_handle);
                               lock(&ei->xattr_sem);
  lock(&sbi->s_writepages_rwsem);

 *** DEADLOCK ***

3 locks held by syz.0.17/4315:
 #0: ffff8880771cc0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229
 #1: ffff8880771cc650 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff8880771cc650 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1928 [inline]
 #1: ffff8880771cc650 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x44a/0x1090 fs/ext4/inode.c:243
 #2: ffff8880602f0ac0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
 #2: ffff8880602f0ac0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5941 [inline]
 #2: ffff8880602f0ac0 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x3e8/0x700 fs/ext4/inode.c:6022

stack backtrace:
CPU: 0 PID: 4315 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 percpu_down_read+0x46/0x1b0 include/linux/percpu-rwsem.h:51
 ext4_writepages+0x20f/0x2df0 fs/ext4/inode.c:2689
 do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
 __writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
 writeback_single_inode+0x3cb/0x8e0 fs/fs-writeback.c:1770
 write_inode_now+0x23b/0x2c0 fs/fs-writeback.c:2811
 iput_final fs/inode.c:1756 [inline]
 iput+0x5ab/0x8a0 fs/inode.c:1795
 ext4_xattr_set_entry+0x34f4/0x3ea0 fs/ext4/xattr.c:1837
 ext4_xattr_block_set+0x4fd/0x2d20 fs/ext4/xattr.c:1936
 ext4_xattr_move_to_block fs/ext4/xattr.c:2633 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2708 [inline]
 ext4_expand_extra_isize_ea+0xf3b/0x1990 fs/ext4/xattr.c:2800
 __ext4_expand_extra_isize+0x301/0x3e0 fs/ext4/inode.c:5901
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5944 [inline]
 __ext4_mark_inode_dirty+0x469/0x700 fs/ext4/inode.c:6022
 ext4_evict_inode+0xa8d/0x1090 fs/ext4/inode.c:282
 evict+0x4c9/0x8d0 fs/inode.c:647
 ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:470
 ext4_fill_super+0x92c9/0x9a40 fs/ext4/super.c:4975
 mount_bdev+0x287/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x24a/0xa40 fs/namespace.c:3034
 do_mount fs/namespace.c:3377 [inline]
 __do_sys_mount fs/namespace.c:3585 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f3d37c73f4a
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc5fb98ee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc5fb98f70 RCX: 00007f3d37c73f4a
RDX: 0000200000000180 RSI: 00002000000001c0 RDI: 00007ffc5fb98f30
RBP: 0000200000000180 R08: 00007ffc5fb98f70 R09: 0000000000800700
R10: 0000000000800700 R11: 0000000000000246 R12: 00002000000001c0
R13: 00007ffc5fb98f30 R14: 000000000000046f R15: 000000000000002c
 </TASK>
EXT4-fs error (device loop0): ext4_xattr_inode_iget:404: inode #11: comm syz.0.17: iget: bad extra_isize 90 (inode size 256)
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_xattr_inode_iget:409: comm syz.0.17: error while reading EA inode 11 err=-117
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs warning (device loop0): ext4_expand_extra_isize_ea:2826: Unable to expand inode 15. Delete some EAs or run e2fsck.
EXT4-fs error (device loop0): ext4_xattr_inode_iget:404: inode #11: comm syz.0.17: iget: bad extra_isize 90 (inode size 256)
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_xattr_inode_iget:409: comm syz.0.17: error while reading EA inode 11 err=-117
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_xattr_inode_iget:404: inode #18: comm syz.0.17: iget: bad extra_isize 90 (inode size 256)
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_xattr_inode_iget:409: comm syz.0.17: error while reading EA inode 18 err=-117
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_xattr_inode_iget:404: inode #18: comm syz.0.17: iget: bad extra_isize 90 (inode size 256)
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs error (device loop0): ext4_xattr_inode_iget:409: comm syz.0.17: error while reading EA inode 18 err=-117
EXT4-fs (loop0): Remounting filesystem read-only
EXT4-fs (loop0): 1 orphan inode deleted
EXT4-fs (loop0): mounted filesystem without journal. Opts: nodioread_nolock,errors=remount-ro,debug_want_extra_isize=0x000000000000005a,nouid32,resgid=0x0000000000000000,acl,init_itable=0x0000000000000003,. Quota mode: none.