[moderation/CI] Re: vfs: add O_CREAT|O_DIRECTORY to open*(2)

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syzbot ci

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May 17, 2026, 5:16:14 PMMay 17
to syzkaller-upst...@googlegroups.com, syz...@lists.linux.dev
syzbot ci has tested the following series

[v3] vfs: add O_CREAT|O_DIRECTORY to open*(2)
https://lore.kernel.org/all/20260517170244.18...@xs4all.nl
* [RFC PATCH v3 1/2] vfs: add O_CREAT|O_DIRECTORY to open*(2)
* [RFC PATCH v3 2/2] selftest: add tests for open*(O_CREAT|O_DIRECTORY)

and found the following issues:
* WARNING: lock held when returning to user space in filename_create
* WARNING: lock held when returning to user space in start_creating
* possible deadlock in mnt_want_write

Full report is available here:
https://ci.syzbot.org/series/6c2681e8-f8f3-4287-8f97-bd6ea26a767f

***

WARNING: lock held when returning to user space in filename_create

tree: torvalds
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base: 6916d5703ddf9a38f1f6c2cc793381a24ee914c6
arch: amd64
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config: https://ci.syzbot.org/builds/7a0474b8-fd0f-4804-8833-2232742e06e3/config
syz repro: https://ci.syzbot.org/findings/512f2832-177b-4b65-b835-bdff3e4402bc/syz_repro

hpfs: hpfs_map_4sectors(): unaligned read
hpfs: hpfs_map_4sectors(): unaligned read
hpfs: filesystem error: unable to find root dir
================================================
WARNING: lock held when returning to user space!
syzkaller #0 Not tainted
------------------------------------------------
syz.0.17/5814 is leaving the kernel with locks still held!
1 lock held by syz.0.17/5814:
#0: ffff8881bab5b878 (&type->i_mutex_dir_key#8/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline]
#0: ffff8881bab5b878 (&type->i_mutex_dir_key#8/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2919 [inline]
#0: ffff8881bab5b878 (&type->i_mutex_dir_key#8/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2943 [inline]
#0: ffff8881bab5b878 (&type->i_mutex_dir_key#8/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4984


***

WARNING: lock held when returning to user space in start_creating

tree: torvalds
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base: 6916d5703ddf9a38f1f6c2cc793381a24ee914c6
arch: amd64
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config: https://ci.syzbot.org/builds/7a0474b8-fd0f-4804-8833-2232742e06e3/config
syz repro: https://ci.syzbot.org/findings/7bdf5f73-8cce-4785-aa9e-dd89622cf613/syz_repro

overlayfs: failed to create directory ./bus/work (errno: 126); mounting read-only
================================================
WARNING: lock held when returning to user space!
syzkaller #0 Not tainted
------------------------------------------------
syz.1.18/5833 is leaving the kernel with locks still held!
1 lock held by syz.1.18/5833:
#0: ffff8881ba0c4518 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline]
#0: ffff8881ba0c4518 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2919 [inline]
#0: ffff8881ba0c4518 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2943 [inline]
#0: ffff8881ba0c4518 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: start_creating+0xbe/0x100 fs/namei.c:3412


***

possible deadlock in mnt_want_write

tree: torvalds
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base: 6916d5703ddf9a38f1f6c2cc793381a24ee914c6
arch: amd64
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config: https://ci.syzbot.org/builds/7a0474b8-fd0f-4804-8833-2232742e06e3/config
syz repro: https://ci.syzbot.org/findings/6d4f386f-fb66-4862-b644-4ac19c79f6a3/syz_repro

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.17/5836 is trying to acquire lock:
ffff888118cba410
(sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493

but task is already holding lock:
ffff88811f1627e0 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline]
ffff88811f1627e0 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2919 [inline]
ffff88811f1627e0 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2943 [inline]
ffff88811f1627e0 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4984

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}:
down_write_nested+0x9d/0x210 kernel/locking/rwsem.c:1751
inode_lock_nested include/linux/fs.h:1074 [inline]
__start_dirop fs/namei.c:2919 [inline]
start_dirop fs/namei.c:2943 [inline]
filename_unlinkat+0x2a7/0x610 fs/namei.c:5599
__do_sys_unlink fs/namei.c:5653 [inline]
__se_sys_unlink+0x2e/0x140 fs/namei.c:5650
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sb_writers#12){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
__sb_start_write include/linux/fs/super.h:19 [inline]
sb_start_write+0x4d/0x1c0 include/linux/fs/super.h:125
mnt_want_write+0x41/0x90 fs/namespace.c:493
filename_create+0x154/0x370 fs/namei.c:4977
filename_mkdirat+0xd2/0x510 fs/namei.c:5337
__do_sys_mkdirat fs/namei.c:5365 [inline]
__se_sys_mkdirat+0x35/0x150 fs/namei.c:5362
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ovl_i_mutex_dir_key[depth]/1);
lock(sb_writers#12);
lock(&ovl_i_mutex_dir_key[depth]/1);
rlock(sb_writers#12);

*** DEADLOCK ***

1 lock held by syz.0.17/5836:
#0: ffff88811f1627e0 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1074 [inline]
#0: ffff88811f1627e0 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2919 [inline]
#0: ffff88811f1627e0 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2943 [inline]
#0: ffff88811f1627e0 (&ovl_i_mutex_dir_key[depth]/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4984

stack backtrace:
CPU: 0 UID: 0 PID: 5836 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
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
__sb_start_write include/linux/fs/super.h:19 [inline]
sb_start_write+0x4d/0x1c0 include/linux/fs/super.h:125
mnt_want_write+0x41/0x90 fs/namespace.c:493
filename_create+0x154/0x370 fs/namei.c:4977
filename_mkdirat+0xd2/0x510 fs/namei.c:5337
__do_sys_mkdirat fs/namei.c:5365 [inline]
__se_sys_mkdirat+0x35/0x150 fs/namei.c:5362
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2f5e99ce59
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:00007f2f5f771028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f2f5ec15fa0 RCX: 00007f2f5e99ce59
RDX: 0000000000000010 RSI: 0000200000002040 RDI: ffffffffffffff9c
RBP: 00007f2f5ea32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2f5ec16038 R14: 00007f2f5ec15fa0 R15: 00007ffe96c961d8
</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: syz...@syzkaller.appspotmail.com

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

To test a patch for this bug, please reply with `#syz test`
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If the report looks fine to you, reply with:
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If the report is a false positive, reply with
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Aleksandr Nogikh

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May 18, 2026, 2:46:02 AMMay 18
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#syz upstream

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Aleksandr Nogikh

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May 18, 2026, 3:27:50 AMMay 18
to syzbot ci, syzkaller-upst...@googlegroups.com, syz...@lists.linux.dev
#syz upstream


On Sun, May 17, 2026 at 11:16 PM syzbot ci
<syzbot+ci965...@syzkaller.appspotmail.com> wrote:
>

syzbot ci

unread,
May 18, 2026, 5:19:39 PMMay 18
to syzkaller-upst...@googlegroups.com, syz...@lists.linux.dev
syzbot ci has tested the following series

[v4] vfs: add O_CREAT|O_DIRECTORY to open*(2)
https://lore.kernel.org/all/20260518165237.20...@xs4all.nl
* [RFC PATCH v4 1/2] vfs: add O_CREAT|O_DIRECTORY to open*(2)
* [RFC PATCH v4 2/2] selftest: add tests for open*(O_CREAT|O_DIRECTORY)

and found the following issues:
* KASAN: slab-out-of-bounds Read in ovl_dir_release
* general protection fault in path_openat

Full report is available here:
https://ci.syzbot.org/series/0d511b6b-6434-45cd-bbf3-51fe9d916e99

***

KASAN: slab-out-of-bounds Read in ovl_dir_release

tree: torvalds
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base: 5200f5f493f79f14bbdc349e402a40dfb32f23c8
arch: amd64
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config: https://ci.syzbot.org/builds/024b677f-50e7-4ef9-ae98-2652f5098bfd/config
syz repro: https://ci.syzbot.org/findings/a7087360-137c-41f5-ae13-db4d551fe142/syz_repro

==================================================================
BUG: KASAN: slab-out-of-bounds in ovl_dir_release+0x228/0x2a0 fs/overlayfs/readdir.c:1033
Read of size 8 at addr ffff88816cd2c818 by task syz.0.17/5813

CPU: 0 UID: 0 PID: 5813 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
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
ovl_dir_release+0x228/0x2a0 fs/overlayfs/readdir.c:1033
__fput+0x44f/0xa60 fs/file_table.c:510
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xf3/0x4d0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe1a159ce59
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:00007ffe25af07f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffe25af08e0 RCX: 00007fe1a159ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000012e15 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b32a20000 R11: 0000000000000246 R12: 00007ffe25af0920
R13: 00007fe1a1815fac R14: 0000000000012e53 R15: 00007fe1a1815fa0
</TASK>

Allocated by task 5814:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5419
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
ovl_file_alloc+0x4f/0x90 fs/overlayfs/file.c:99
ovl_create_tmpfile fs/overlayfs/dir.c:1399 [inline]
ovl_tmpfile+0x3fc/0x7d0 fs/overlayfs/dir.c:1448
vfs_tmpfile+0x3ff/0x890 fs/namei.c:4794
do_tmpfile+0xd3/0x240 fs/namei.c:4859
path_openat+0x33c7/0x3b40 fs/namei.c:4893
do_file_open+0x23e/0x4a0 fs/namei.c:4931
do_sys_openat2+0x113/0x200 fs/open.c:1367
do_sys_open fs/open.c:1373 [inline]
__do_sys_open fs/open.c:1381 [inline]
__se_sys_open fs/open.c:1377 [inline]
__x64_sys_open+0x11e/0x150 fs/open.c:1377
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88816cd2c800
which belongs to the cache kmalloc-16 of size 16
The buggy address is located 8 bytes to the right of
allocated 16-byte region [ffff88816cd2c800, ffff88816cd2c810)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88816cd2c840 pfn:0x16cd2c
flags: 0x57ff00000000200(workingset|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000200 ffff888100041640 ffff888160400408 ffff888160400408
raw: ffff88816cd2c840 0000000800800042 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 5741, tgid 5741 (syz-executor), ts 77437404410, free_ts 77431264562
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
prep_new_page mm/page_alloc.c:1866 [inline]
get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
alloc_slab_page mm/slub.c:3278 [inline]
allocate_slab+0x77/0x660 mm/slub.c:3467
new_slab mm/slub.c:3525 [inline]
___slab_alloc+0x154/0x6c0 mm/slub.c:4444
__slab_alloc_node mm/slub.c:4510 [inline]
slab_alloc_node mm/slub.c:4886 [inline]
__do_kmalloc_node mm/slub.c:5294 [inline]
__kvmalloc_node_noprof+0x34d/0x8a0 mm/slub.c:6832
xt_jumpstack_alloc net/netfilter/x_tables.c:1449 [inline]
do_replace_table+0x191/0x620 net/netfilter/x_tables.c:1486
xt_register_table+0x269/0x960 net/netfilter/x_tables.c:1596
ip6t_register_table+0x16b/0x330 net/ipv6/netfilter/ip6_tables.c:1754
ip6table_raw_table_init+0x54/0x80 net/ipv6/netfilter/ip6table_raw.c:48
xt_find_table_lock+0x30c/0x3f0 net/netfilter/x_tables.c:1353
xt_request_find_table_lock+0x26/0x100 net/netfilter/x_tables.c:1378
get_info net/ipv6/netfilter/ip6_tables.c:979 [inline]
do_ip6t_get_ctl+0x716/0x1230 net/ipv6/netfilter/ip6_tables.c:1668
nf_getsockopt+0x26e/0x290 net/netfilter/nf_sockopt.c:116
ipv6_getsockopt+0x1fd/0x2b0 net/ipv6/ipv6_sockglue.c:1464
do_sock_getsockopt+0x51d/0x7e0 net/socket.c:2487
page last free pid 15 tgid 15 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1402 [inline]
__free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943
rcu_do_batch kernel/rcu/tree.c:2617 [inline]
rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
kthread+0x389/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
ffff88816cd2c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88816cd2c780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88816cd2c800: 00 00 fc fc 00 00 fc fc fc fc fc fc fc fc fc fc
^
ffff88816cd2c880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88816cd2c900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


***

general protection fault in path_openat

tree: torvalds
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base: 5200f5f493f79f14bbdc349e402a40dfb32f23c8
arch: amd64
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config: https://ci.syzbot.org/builds/024b677f-50e7-4ef9-ae98-2652f5098bfd/config
syz repro: https://ci.syzbot.org/findings/4b3b0fe3-064c-43e2-b887-b3a52d87a16a/syz_repro

BTRFS info (device loop1): enabling ssd optimizations
BTRFS info (device loop1): turning on async discard
BTRFS info (device loop1): enabling free space tree
BTRFS info (device loop1): use zstd compression, level 3
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 5849 Comm: syz.1.18 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_entry_type include/linux/dcache.h:429 [inline]
RIP: 0010:d_can_lookup include/linux/dcache.h:444 [inline]
RIP: 0010:do_open fs/namei.c:4726 [inline]
RIP: 0010:path_openat+0x2e66/0x3b40 fs/namei.c:4902
Code: e8 8f 49 7f ff eb 62 48 8b 44 24 78 42 80 3c 20 00 48 8b 5c 24 68 74 08 48 89 df e8 44 87 ea ff 4c 8b 3b 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 cb 09 00 00 41 bc 00 00 38 00 45 23 27
RSP: 0018:ffffc9000405f960 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffc9000405fc28 RCX: 0000000000000000
RDX: ffff88810fe50000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc9000405fbb0 R08: ffff8881b949469b R09: 1ffff110372928d3
R10: dffffc0000000000 R11: ffffed10372928d4 R12: dffffc0000000000
R13: 1ffff1102eb65c88 R14: 000000000015d0c0 R15: 0000000000000001
FS: 00007f074937f6c0(0000) GS:ffff8882a928a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000c2113360000 CR3: 0000000103f3a000 CR4: 00000000000006f0
Call Trace:
<TASK>
do_file_open+0x23e/0x4a0 fs/namei.c:4931
do_sys_openat2+0x113/0x200 fs/open.c:1367
do_sys_open fs/open.c:1373 [inline]
__do_sys_openat fs/open.c:1389 [inline]
__se_sys_openat fs/open.c:1384 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1384
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f074859ce59
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:00007f074937f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0748815fa0 RCX: 00007f074859ce59
RDX: 00000000001dd0c0 RSI: 0000200000000240 RDI: ffffffffffffff9c
RBP: 00007f0748632d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0748816038 R14: 00007f0748815fa0 R15: 00007fff34fee548
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__d_entry_type include/linux/dcache.h:429 [inline]
RIP: 0010:d_can_lookup include/linux/dcache.h:444 [inline]
RIP: 0010:do_open fs/namei.c:4726 [inline]
RIP: 0010:path_openat+0x2e66/0x3b40 fs/namei.c:4902
Code: e8 8f 49 7f ff eb 62 48 8b 44 24 78 42 80 3c 20 00 48 8b 5c 24 68 74 08 48 89 df e8 44 87 ea ff 4c 8b 3b 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 cb 09 00 00 41 bc 00 00 38 00 45 23 27
RSP: 0018:ffffc9000405f960 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffc9000405fc28 RCX: 0000000000000000
RDX: ffff88810fe50000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc9000405fbb0 R08: ffff8881b949469b R09: 1ffff110372928d3
R10: dffffc0000000000 R11: ffffed10372928d4 R12: dffffc0000000000
R13: 1ffff1102eb65c88 R14: 000000000015d0c0 R15: 0000000000000001
FS: 00007f074937f6c0(0000) GS:ffff8882a928a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1c7a2f73b0 CR3: 0000000103f3a000 CR4: 00000000000006f0
----------------
Code disassembly (best guess):
0: e8 8f 49 7f ff call 0xff7f4994
5: eb 62 jmp 0x69
7: 48 8b 44 24 78 mov 0x78(%rsp),%rax
c: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1)
11: 48 8b 5c 24 68 mov 0x68(%rsp),%rbx
16: 74 08 je 0x20
18: 48 89 df mov %rbx,%rdi
1b: e8 44 87 ea ff call 0xffea8764
20: 4c 8b 3b mov (%rbx),%r15
23: 4c 89 f8 mov %r15,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 0f b6 04 20 movzbl (%rax,%r12,1),%eax <-- trapping instruction
2f: 84 c0 test %al,%al
31: 0f 85 cb 09 00 00 jne 0xa02
37: 41 bc 00 00 38 00 mov $0x380000,%r12d
3d: 45 23 27 and (%r15),%r12d


***

If these findings have caused you to resend the series or submit a
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Tested-by: syz...@syzkaller.appspotmail.com

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Aleksandr Nogikh

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May 19, 2026, 2:57:12 AMMay 19
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