Re: [moderation/CI] Re: ext4: deferred iput framework for EA inodes

#syz upstream

On Tue, Jun 23, 2026 at 3:07 PM syzbot ci
<[email protected]> wrote:
>
> syzbot ci has tested the following series
>
> [v9] ext4: deferred iput framework for EA inodes
> https://lore.kernel.org/all/[email protected]
> * [PATCH v9 1/4] fs: add iput_if_not_last() helper
> * [PATCH v9 2/4] ext4: introduce ext4_put_ea_inode() for safe deferred iput
> * [PATCH v9 3/4] ext4: convert all EA inode iput() calls to ext4_put_ea_inode()
> * [PATCH v9 4/4] ext4: remove ea_inode_array mechanism in favor of ext4_put_ea_inode()
>
> and found the following issue:
> WARNING: ODEBUG bug in flush_delayed_work
>
> Full report is available here:
> https://ci.syzbot.org/series/acc1a7bd-816f-451e-86ee-a62f88ad8fcc
>
> ***
>
> WARNING: ODEBUG bug in flush_delayed_work
>
> tree:      torvalds
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
> base:      502d801f0ab03e4f32f9a33d203154ce84887921
> arch:      amd64
> compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
> config:    https://ci.syzbot.org/builds/79d2cdf0-fde6-4e70-a88c-04d44c9d3e44/config
> syz repro: https://ci.syzbot.org/findings/9b2e3f5d-279a-469f-9f2a-05f96ea11587/syz_repro
>
> EXT4-fs warning (device loop2): ext4_multi_mount_protect:287: Invalid MMP block in superblock
> ------------[ cut here ]------------
> ODEBUG: assert_init not available (active state 0) object: ffff8881bf08c9e0 object type: timer_list hint: 0x0
> WARNING: lib/debugobjects.c:632 at debug_print_object+0xec/0x230 lib/debugobjects.c:629, CPU#1: syz.2.19/5833
> Modules linked in:
> CPU: 1 UID: 0 PID: 5833 Comm: syz.2.19 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> RIP: 0010:debug_print_object+0x18a/0x230 lib/debugobjects.c:629
> Code: f8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ff e8 5d 04 71 fd 4d 8b 0f 4c 89 ef 48 8b 74 24 08 48 89 ea 44 89 e1 4d 89 f0 ff 34 24 <67> 48 0f b9 3a 48 83 c4 08 ff 05 a3 23 70 0b 48 83 c4 10 5b 41 5c
> RSP: 0018:ffffc9000179f848 EFLAGS: 00010046
>
> RAX: 1ffffffff179eacc RBX: dffffc0000000000 RCX: 0000000000000000
> RDX: ffffffff8c2a9980 RSI: ffffffff8c2a93e0 RDI: ffffffff903ddbf0
> RBP: ffffffff8c2a9980 R08: ffff8881bf08c9e0 R09: ffffffff8bcf69c0
> R10: dffffc0000000000 R11: ffffffff81b25990 R12: 0000000000000000
> R13: ffffffff903ddbf0 R14: ffff8881bf08c9e0 R15: ffffffff8bcf5660
> FS:  00007fd11e12e6c0(0000) GS:ffff8882a922d000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007ffe46d80f88 CR3: 00000001bf40e000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  debug_object_assert_init+0x237/0x370 lib/debugobjects.c:1075
>  debug_timer_assert_init kernel/time/timer.c:803 [inline]
>  debug_assert_init kernel/time/timer.c:848 [inline]
>  __try_to_del_timer_sync kernel/time/timer.c:1457 [inline]
>  __timer_delete_sync+0x181/0x520 kernel/time/timer.c:1621
>  flush_delayed_work+0x48/0x100 kernel/workqueue.c:4414
>  ext4_drain_ea_inode_work fs/ext4/xattr.h:196 [inline]
>  __ext4_fill_super fs/ext4/super.c:5795 [inline]
>  ext4_fill_super+0x54c7/0x66d0 fs/ext4/super.c:5844
>  get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1634
>  vfs_get_tree+0x92/0x2a0 fs/super.c:1694
>  fc_mount fs/namespace.c:1198 [inline]
>  do_new_mount_fc fs/namespace.c:3765 [inline]
>  do_new_mount+0x319/0xdc0 fs/namespace.c:3841
>  do_mount fs/namespace.c:4174 [inline]
>  __do_sys_mount fs/namespace.c:4390 [inline]
>  __se_sys_mount+0x31d/0x420 fs/namespace.c:4367
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fd11d19e0ca
> 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:00007fd11e12de58 EFLAGS: 00000246
>  ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007fd11e12dee0 RCX: 00007fd11d19e0ca
> RDX: 0000200000000400 RSI: 0000200000000340 RDI: 00007fd11e12dea0
> RBP: 0000200000000400 R08: 00007fd11e12dee0 R09: 000000000021c91c
> R10: 000000000021c91c R11: 0000000000000246 R12: 0000200000000340
> R13: 00007fd11e12dea0 R14: 000000000000051a R15: 0000200000000240
>  </TASK>
> ----------------
> Code disassembly (best guess):
>    0:   f8                      clc
>    1:   48 c1 e8 03             shr    $0x3,%rax
>    5:   80 3c 18 00             cmpb   $0x0,(%rax,%rbx,1)
>    9:   74 08                   je     0x13
>    b:   4c 89 ff                mov    %r15,%rdi
>    e:   e8 5d 04 71 fd          call   0xfd710470
>   13:   4d 8b 0f                mov    (%r15),%r9
>   16:   4c 89 ef                mov    %r13,%rdi
>   19:   48 8b 74 24 08          mov    0x8(%rsp),%rsi
>   1e:   48 89 ea                mov    %rbp,%rdx
>   21:   44 89 e1                mov    %r12d,%ecx
>   24:   4d 89 f0                mov    %r14,%r8
>   27:   ff 34 24                push   (%rsp)
> * 2a:   67 48 0f b9 3a          ud1    (%edx),%rdi <-- trapping instruction
>   2f:   48 83 c4 08             add    $0x8,%rsp
>   33:   ff 05 a3 23 70 0b       incl   0xb7023a3(%rip)        # 0xb7023dc
>   39:   48 83 c4 10             add    $0x10,%rsp
>   3d:   5b                      pop    %rbx
>   3e:   41 5c                   pop    %r12
>
>
> ***
>
> If these findings have caused you to resend the series or submit a
> separate fix, please add the following tag to your commit message:
>   Tested-by: [email protected]
>
> ---
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