[moderation/CI] Re: multiple-filesystems: prepare for changes to VFS locking

[moderation/CI] Re: multiple-filesystems: prepare for changes to VFS locking

[syzbot ci]

syzbot ci has tested the following series

[v1] multiple-filesystems: prepare for changes to VFS locking
https://lore.kernel.org/all/20260929034158.1455429-1-neilb@ownmail.net
* [PATCH 1/7] VFS/xfs/ntfs: drop parent lock across d_alloc_parallel() in d_add_ci()
* [PATCH 2/7] shmem: use d_duplicate()
* [PATCH 3/7] coda: don't d_drop() early.
* [PATCH 4/7] configfs: remove d_add() calls before configfs_attach_group()
* [PATCH 5/7] hostfs: don't d_drop() before d_splice_alias() in hostfs_mkdir()
* [PATCH 6/7] procfs: drop parent lock for d_alloc_parallel() in iterate_shared()
* [PATCH 7/7] ovl: stop using lookup_one() in ovl_iterate().

and found the following issue:
WARNING in __d_instantiate

Full report is available here:
https://ci.syzbot.org/series/b87296ff-c49f-416e-834c-a886ea8bd6c3

***

WARNING in __d_instantiate

tree:      linux-next
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next
base:      3879f51857325da9bf3cfb073280257cd16ae067
arch:      amd64
compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
config:    https://ci.syzbot.org/builds/dd8fcfa5-13f0-458f-bd3b-9c06d4d67a78/config
syz repro: https://ci.syzbot.org/findings/fdffe42d-ac1a-40d9-b05c-014808f5b0ec/syz_repro

------------[ cut here ]------------
d_in_lookup(dentry)
WARNING: fs/dcache.c:2197 at __d_instantiate+0x3f4/0x700 fs/dcache.c:2197, CPU#1: syz.0.17/5823
Modules linked in:
CPU: 1 UID: 0 PID: 5823 Comm: syz.0.17 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:__d_instantiate+0x3f4/0x700 fs/dcache.c:2197
Code: 03 41 80 f6 01 41 0f b6 ce c1 e1 0d 09 c1 89 0b 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d e9 03 26 96 09 cc e8 0d 84 75 ff 90 <0f> 0b 90 e9 7f fd ff ff e8 ff 83 75 ff 41 81 cc 00 00 01 00 e9 34
RSP: 0018:ffffc900038d73a0 EFLAGS: 00010293
RAX: ffffffff825242a3 RBX: ffff8881b4eef380 RCX: ffff888169801e00
RDX: 0000000000000000 RSI: 0000000001000000 RDI: 0000000000000000
RBP: 0000000001000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200071ae6c R12: 0000000000280000
R13: dffffc0000000000 R14: ffff8881bc29f3e0 R15: ffff8881bc29f3e4
FS:  00007f15d1af96c0(0000) GS:ffff8882a8cc9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 00000001bd5c4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 d_make_persistent+0x8e/0x180 fs/dcache.c:3139
 shmem_mknod+0x2d4/0x340 mm/shmem.c:3851
 shmem_whiteout mm/shmem.c:3982 [inline]
 shmem_rename2+0x267/0x430 mm/shmem.c:4022
 vfs_rename+0xbd9/0xef0 fs/namei.c:6219
 ovl_do_rename_rd fs/overlayfs/overlayfs.h:371 [inline]
 ovl_check_rename_whiteout fs/overlayfs/super.c:593 [inline]
 ovl_make_workdir fs/overlayfs/super.c:713 [inline]
 ovl_get_workdir+0x93d/0x1980 fs/overlayfs/super.c:836
 ovl_fill_super_creds fs/overlayfs/super.c:1449 [inline]
 ovl_fill_super+0x1702/0x4360 fs/overlayfs/super.c:1561
 vfs_get_super fs/super.c:1405 [inline]
 get_tree_nodev+0xbb/0x150 fs/super.c:1424
 vfs_get_tree+0x92/0x2a0 fs/super.c:1947
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3772 [inline]
 do_new_mount+0x319/0xdc0 fs/namespace.c:3848
 do_mount fs/namespace.c:4181 [inline]
 __do_sys_mount fs/namespace.c:4397 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4374
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f15d0b9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f15d1af9028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f15d0e25fa0 RCX: 00007f15d0b9e159
RDX: 0000200000000440 RSI: 0000200000000100 RDI: 0000000000000000
RBP: 00007f15d0c3506b R08: 0000200000000080 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f15d0e26038 R14: 00007f15d0e25fa0 R15: 00007ffe9e1b3308
 </TASK>


***

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: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.

To test a fix for this bug, please reply with `#syz test`
(on a separate line) and attach the patch to the email.

Notes:
- The patch will be applied on top of the tested series (as an
  incremental fix).
- To test a new version of the whole series, please send it directly
  to syzbot@lists.linux.dev.
- Arguments like custom git repos and branches are not supported.

The email will later be sent to:
[a.hindborg@kernel.org amir73il@gmail.com anton.ivanov@cambridgegreys.com baolin.wang@linux.alibaba.com brauner@kernel.org cem@kernel.org coda@cs.cmu.edu codalist@coda.cs.cmu.edu fuse-devel@lists.linux.dev hughd@google.com hyc.lee@gmail.com jack@suse.cz jaharkes@cs.cmu.edu jlayton@kernel.org joel.granados@kernel.org johannes@sipsolutions.net kees@kernel.org leitao@debian.org linkinjeon@kernel.org linux-fsdevel@vger.kernel.org linux-kernel@vger.kernel.org linux-mm@kvack.org linux-um@lists.infradead.org linux-unionfs@vger.kernel.org linux-xfs@vger.kernel.org miklos@szeredi.hu neilb@ownmail.net ntfs@lists.linux.dev richard@nod.at viro@zeniv.linux.org.uk]

If the report looks fine to you, reply with:
#syz upstream

If the report is a false positive, reply with
#syz invalid

Re: [moderation/CI] Re: multiple-filesystems: prepare for changes to VFS locking

[Aleksandr Nogikh]

#syz upstream

On Wed, Sep 30, 2026 at 12:19 PM syzbot ci
<syzbot+cie5f097f0663789ec@syzkaller.appspotmail.com> wrote:
>
> syzbot ci has tested the following series
>
> [v1] multiple-filesystems: prepare for changes to VFS locking
> https://lore.kernel.org/all/20260929034158.1455429-1-neilb@ownmail.net
> * [PATCH 1/7] VFS/xfs/ntfs: drop parent lock across d_alloc_parallel() in d_add_ci()
> * [PATCH 2/7] shmem: use d_duplicate()
> * [PATCH 3/7] coda: don't d_drop() early.
> * [PATCH 4/7] configfs: remove d_add() calls before configfs_attach_group()
> * [PATCH 5/7] hostfs: don't d_drop() before d_splice_alias() in hostfs_mkdir()
> * [PATCH 6/7] procfs: drop parent lock for d_alloc_parallel() in iterate_shared()
> * [PATCH 7/7] ovl: stop using lookup_one() in ovl_iterate().
>
> and found the following issue:
> WARNING in __d_instantiate
>
> Full report is available here:
> https://ci.syzbot.org/series/b87296ff-c49f-416e-834c-a886ea8bd6c3
>
> ***
>
> WARNING in __d_instantiate
>
> tree:      linux-next
> URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next
> base:      3879f51857325da9bf3cfb073280257cd16ae067
> arch:      amd64
> compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
> config:    https://ci.syzbot.org/builds/dd8fcfa5-13f0-458f-bd3b-9c06d4d67a78/config
> syz repro: https://ci.syzbot.org/findings/fdffe42d-ac1a-40d9-b05c-014808f5b0ec/syz_repro
>
> ------------[ cut here ]------------
> d_in_lookup(dentry)
> WARNING: fs/dcache.c:2197 at __d_instantiate+0x3f4/0x700 fs/dcache.c:2197, CPU#1: syz.0.17/5823
> Modules linked in:
> CPU: 1 UID: 0 PID: 5823 Comm: syz.0.17 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:__d_instantiate+0x3f4/0x700 fs/dcache.c:2197
> Code: 03 41 80 f6 01 41 0f b6 ce c1 e1 0d 09 c1 89 0b 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d e9 03 26 96 09 cc e8 0d 84 75 ff 90 <0f> 0b 90 e9 7f fd ff ff e8 ff 83 75 ff 41 81 cc 00 00 01 00 e9 34
> RSP: 0018:ffffc900038d73a0 EFLAGS: 00010293
> RAX: ffffffff825242a3 RBX: ffff8881b4eef380 RCX: ffff888169801e00
> RDX: 0000000000000000 RSI: 0000000001000000 RDI: 0000000000000000
> RBP: 0000000001000000 R08: 0000000000000003 R09: 0000000000000004
> R10: dffffc0000000000 R11: fffff5200071ae6c R12: 0000000000280000
> R13: dffffc0000000000 R14: ffff8881bc29f3e0 R15: ffff8881bc29f3e4
> FS:  00007f15d1af96c0(0000) GS:ffff8882a8cc9000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000200000001000 CR3: 00000001bd5c4000 CR4: 00000000000006f0
> Call Trace:
>  <TASK>
>  d_make_persistent+0x8e/0x180 fs/dcache.c:3139
>  shmem_mknod+0x2d4/0x340 mm/shmem.c:3851
>  shmem_whiteout mm/shmem.c:3982 [inline]
>  shmem_rename2+0x267/0x430 mm/shmem.c:4022
>  vfs_rename+0xbd9/0xef0 fs/namei.c:6219
>  ovl_do_rename_rd fs/overlayfs/overlayfs.h:371 [inline]
>  ovl_check_rename_whiteout fs/overlayfs/super.c:593 [inline]
>  ovl_make_workdir fs/overlayfs/super.c:713 [inline]
>  ovl_get_workdir+0x93d/0x1980 fs/overlayfs/super.c:836
>  ovl_fill_super_creds fs/overlayfs/super.c:1449 [inline]
>  ovl_fill_super+0x1702/0x4360 fs/overlayfs/super.c:1561
>  vfs_get_super fs/super.c:1405 [inline]
>  get_tree_nodev+0xbb/0x150 fs/super.c:1424
>  vfs_get_tree+0x92/0x2a0 fs/super.c:1947
>  fc_mount fs/namespace.c:1198 [inline]
>  do_new_mount_fc fs/namespace.c:3772 [inline]
>  do_new_mount+0x319/0xdc0 fs/namespace.c:3848
>  do_mount fs/namespace.c:4181 [inline]
>  __do_sys_mount fs/namespace.c:4397 [inline]
>  __se_sys_mount+0x31d/0x420 fs/namespace.c:4374
>  do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
>  do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f15d0b9e159
> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f15d1af9028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
> RAX: ffffffffffffffda RBX: 00007f15d0e25fa0 RCX: 00007f15d0b9e159
> RDX: 0000200000000440 RSI: 0000200000000100 RDI: 0000000000000000
> RBP: 00007f15d0c3506b R08: 0000200000000080 R09: 0000000000000000
> R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f15d0e26038 R14: 00007f15d0e25fa0 R15: 00007ffe9e1b3308
>  </TASK>
>
>
> ***
>
> 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: syzbot@syzkaller.appspotmail.com
>
> ---
> This report is generated by a bot. It may contain errors.
> syzbot ci engineers can be reached at syzkaller@googlegroups.com.
>
> To test a fix for this bug, please reply with `#syz test`
> (on a separate line) and attach the patch to the email.
>
> Notes:
> - The patch will be applied on top of the tested series (as an
>   incremental fix).
> - To test a new version of the whole series, please send it directly
>   to syzbot@lists.linux.dev.
> - Arguments like custom git repos and branches are not supported.
>
> The email will later be sent to:
> [a.hindborg@kernel.org amir73il@gmail.com anton.ivanov@cambridgegreys.com baolin.wang@linux.alibaba.com brauner@kernel.org cem@kernel.org coda@cs.cmu.edu codalist@coda.cs.cmu.edu fuse-devel@lists.linux.dev hughd@google.com hyc.lee@gmail.com jack@suse.cz jaharkes@cs.cmu.edu jlayton@kernel.org joel.granados@kernel.org johannes@sipsolutions.net kees@kernel.org leitao@debian.org linkinjeon@kernel.org linux-fsdevel@vger.kernel.org linux-kernel@vger.kernel.org linux-mm@kvack.org linux-um@lists.infradead.org linux-unionfs@vger.kernel.org linux-xfs@vger.kernel.org miklos@szeredi.hu neilb@ownmail.net ntfs@lists.linux.dev richard@nod.at viro@zeniv.linux.org.uk]
>
> If the report looks fine to you, reply with:
> #syz upstream
>
> If the report is a false positive, reply with
> #syz invalid
>
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