[syzbot] [dri?] [reiserfs?] WARNING: bad unlock balance in vkms_vblank_simulate

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 71cd4fc492ec Add linux-next specific files for 20230808
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11faa1eda80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e36b5ba725f7349d
dashboard link: https://syzkaller.appspot.com/bug?extid=5671b8bcd5178fe56c23
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17a54d0ba80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13e2281ba80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5ea26a69f422/disk-71cd4fc4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c4a6b00863bf/vmlinux-71cd4fc4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/888c2025ec30/bzImage-71cd4fc4.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/3620b064e309/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5671b8...@syzkaller.appspotmail.com

=====================================
WARNING: bad unlock balance detected!
6.5.0-rc5-next-20230808-syzkaller #0 Not tainted
-------------------------------------
swapper/0/0 is trying to release lock (&vkms_out->enabled_lock) at:
[<ffffffff852badf9>] vkms_vblank_simulate+0x159/0x3d0 drivers/gpu/drm/vkms/vkms_crtc.c:34
but there are no more locks to release!

other info that might help us debug this:
no locks held by swapper/0/0.

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.5.0-rc5-next-20230808-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
__lock_release kernel/locking/lockdep.c:5438 [inline]
lock_release+0x4b5/0x680 kernel/locking/lockdep.c:5781
__mutex_unlock_slowpath+0xa3/0x640 kernel/locking/mutex.c:907
vkms_vblank_simulate+0x159/0x3d0 drivers/gpu/drm/vkms/vkms_crtc.c:34
__run_hrtimer kernel/time/hrtimer.c:1688 [inline]
__hrtimer_run_queues+0x203/0xc10 kernel/time/hrtimer.c:1752
hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1098 [inline]
__sysvec_apic_timer_interrupt+0x14a/0x430 arch/x86/kernel/apic/apic.c:1115
sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1109
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline]
RIP: 0010:acpi_safe_halt+0x1b/0x20 drivers/acpi/processor_idle.c:113
Code: ed c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 65 48 8b 04 25 c0 bc 03 00 48 8b 00 a8 08 75 0c 66 90 0f 00 2d 57 9d 99 00 fb f4 <fa> c3 0f 1f 00 0f b6 47 08 3c 01 74 0b 3c 02 74 05 8b 7f 04 eb 9f
RSP: 0000:ffffffff8c607d70 EFLAGS: 00000246
RAX: 0000000000004000 RBX: 0000000000000001 RCX: ffffffff8a3a232e
RDX: 0000000000000001 RSI: ffff888144e77800 RDI: ffff888144e77864
RBP: ffff888144e77864 R08: 0000000000000001 R09: ffffed1017306dbd
R10: ffff8880b9836deb R11: 0000000000000000 R12: ffff888141ed8000
R13: ffffffff8d45c680 R14: 0000000000000000 R15: 0000000000000000
acpi_idle_enter+0xc5/0x160 drivers/acpi/processor_idle.c:707
cpuidle_enter_state+0x82/0x500 drivers/cpuidle/cpuidle.c:267
cpuidle_enter+0x4e/0xa0 drivers/cpuidle/cpuidle.c:388
cpuidle_idle_call kernel/sched/idle.c:215 [inline]
do_idle+0x315/0x3f0 kernel/sched/idle.c:282
cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:379
rest_init+0x16f/0x2b0 init/main.c:726
arch_call_rest_init+0x13/0x30 init/main.c:823
start_kernel+0x39f/0x480 init/main.c:1068
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:556
x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:537
secondary_startup_64_no_verify+0x167/0x16b
</TASK>
----------------
Code disassembly (best guess):
0: ed in (%dx),%eax
1: c3 ret
2: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1)
9: 00 00 00 00
d: 66 90 xchg %ax,%ax
f: 65 48 8b 04 25 c0 bc mov %gs:0x3bcc0,%rax
16: 03 00
18: 48 8b 00 mov (%rax),%rax
1b: a8 08 test $0x8,%al
1d: 75 0c jne 0x2b
1f: 66 90 xchg %ax,%ax
21: 0f 00 2d 57 9d 99 00 verw 0x999d57(%rip) # 0x999d7f
28: fb sti
29: f4 hlt
* 2a: fa cli <-- trapping instruction
2b: c3 ret
2c: 0f 1f 00 nopl (%rax)
2f: 0f b6 47 08 movzbl 0x8(%rdi),%eax
33: 3c 01 cmp $0x1,%al
35: 74 0b je 0x42
37: 3c 02 cmp $0x2,%al
39: 74 05 je 0x40
3b: 8b 7f 04 mov 0x4(%rdi),%edi
3e: eb 9f jmp 0xffffffdf


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Hillf Danton]

On Sun, 13 Aug 2023 00:24:12 -0700

> HEAD commit: 71cd4fc492ec Add linux-next specific files for 20230808
> git tree: linux-next

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13e2281ba80000

Replace mutex with semaphore.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 71cd4fc492ec

--- a/drivers/gpu/drm/vkms/vkms_composer.c
+++ b/drivers/gpu/drm/vkms/vkms_composer.c
@@ -408,7 +408,7 @@ void vkms_set_composer(struct vkms_outpu
if (enabled)
drm_crtc_vblank_get(&out->crtc);

- mutex_lock(&out->enabled_lock);
+ down(&out->enabled_lock);
old_enabled = out->composer_enabled;
out->composer_enabled = enabled;

@@ -416,7 +416,7 @@ void vkms_set_composer(struct vkms_outpu
* will be balanced even if we have a failed commit
*/
if (!out->composer_enabled)
- mutex_unlock(&out->enabled_lock);
+ up(&out->enabled_lock);

if (old_enabled)
drm_crtc_vblank_put(&out->crtc);
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -31,7 +31,7 @@ static enum hrtimer_restart vkms_vblank_

state = output->composer_state;
composer_enabled = output->composer_enabled;
- mutex_unlock(&output->enabled_lock);
+ up(&output->enabled_lock);

if (state && composer_enabled) {
u64 frame = drm_crtc_accurate_vblank_count(crtc);
@@ -295,7 +295,7 @@ int vkms_crtc_init(struct drm_device *de

spin_lock_init(&vkms_out->lock);
spin_lock_init(&vkms_out->composer_lock);
- mutex_init(&vkms_out->enabled_lock);
+ sema_init(&vkms_out->enabled_lock, 1);

vkms_out->composer_workq = alloc_ordered_workqueue("vkms_composer", 0);
if (!vkms_out->composer_workq)
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -4,6 +4,7 @@
#define _VKMS_DRV_H_

#include <linux/hrtimer.h>
+#include <linux/semaphore.h>

#include <drm/drm.h>
#include <drm/drm_framebuffer.h>
@@ -109,7 +110,7 @@ struct vkms_output {
/* protects concurrent access to composer */
spinlock_t lock;
/* guarantees that if the composer is enabled, a job will be queued */
- struct mutex enabled_lock;
+ struct semaphore enabled_lock;

/* protected by @enabled_lock */
bool composer_enabled;
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in cpuacct_charge

REISERFS (device loop0): journal params: device loop0, size 512, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using r5 hash to sort names
REISERFS (device loop0): using 3.5.x disk format
general protection fault, probably for non-canonical address 0xdffffc0020008027: 0000 [#1] PREEMPT SMP KASAN
KASAN: probably user-memory-access in range [0x0000000100040138-0x000000010004013f]
CPU: 0 PID: 5465 Comm: syz-executor.0 Not tainted 6.5.0-rc5-next-20230808-syzkaller-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

RIP: 0010:cpuacct_charge+0x194/0x3e0 kernel/sched/cpuacct.c:342
Code: 85 ed 0f 84 89 00 00 00 49 bc 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 4c 01 e2 48 8d bd 18 01 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 99 01 00 00 48 8b 9d 18 01 00 00 49 83 fd 07
RSP: 0018:ffffc90004d86ba0 EFLAGS: 00010006
RAX: 0000000020008027 RBX: ffff8880b980ff01 RCX: 0000000000000001
RDX: fffffbfff1876d40 RSI: ffffffff8a6c9c60 RDI: 0000000100040138
RBP: 0000000100040020 R08: 0000000000000000 R09: fffffbfff1d5a29a
R10: ffffffff8ead14d7 R11: 0000000000000800 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff8c3b6a00 R15: 000000000046b680
FS: 00007fd3413446c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000ff01 CR3: 000000007db2c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
cgroup_account_cputime include/linux/cgroup.h:718 [inline]
update_curr+0x550/0xaf0 kernel/sched/fair.c:1125
put_prev_entity+0xa2/0x170 kernel/sched/fair.c:5223
pick_next_task_fair+0x783/0x1200 kernel/sched/fair.c:8123
__pick_next_task kernel/sched/core.c:6014 [inline]
pick_next_task kernel/sched/core.c:6089 [inline]
__schedule+0x493/0x59f0 kernel/sched/core.c:6675
preempt_schedule_irq+0x52/0x90 kernel/sched/core.c:7023
irqentry_exit+0x35/0x80 kernel/entry/common.c:433
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:650
RIP: 0010:memmove+0x28/0x1b0 arch/x86/lib/memmove_64.S:44
Code: c3 90 f3 0f 1e fa 48 89 f8 48 39 fe 7d 0f 49 89 f0 49 01 d0 49 39 f8 0f 8f b5 00 00 00 48 83 fa 20 0f 82 01 01 00 00 48 89 d1 <f3> a4 c3 48 81 fa a8 02 00 00 72 05 40 38 fe 74 47 48 83 ea 20 48
RSP: 0018:ffffc90004d86f20 EFLAGS: 00010286
RAX: ffff8880656ccfb4 RBX: 0000000000000002 RCX: fffffffffd51ea6e
RDX: ffffffffffffffe0 RSI: ffff8880681ae516 RDI: ffff8880681ae526
RBP: 0000000000000020 R08: ffff8880656ccf84 R09: 0000766972705f73
R10: 667265736965722e R11: 0000766972705f73 R12: 0000000000000001
R13: 0000000000000000 R14: ffff8880656ccfa4 R15: 0000000000000010
leaf_paste_entries+0x43c/0x920 fs/reiserfs/lbalance.c:1377
balance_leaf_finish_node_paste_dirent fs/reiserfs/do_balan.c:1295 [inline]
balance_leaf_finish_node_paste fs/reiserfs/do_balan.c:1321 [inline]
balance_leaf_finish_node fs/reiserfs/do_balan.c:1364 [inline]
balance_leaf+0x9476/0xcd90 fs/reiserfs/do_balan.c:1452
do_balance+0x337/0x840 fs/reiserfs/do_balan.c:1888
reiserfs_paste_into_item+0x62a/0x7c0 fs/reiserfs/stree.c:2157
reiserfs_add_entry+0x936/0xd20 fs/reiserfs/namei.c:565
reiserfs_mkdir+0x68a/0x9a0 fs/reiserfs/namei.c:860
xattr_mkdir fs/reiserfs/xattr.c:77 [inline]
create_privroot fs/reiserfs/xattr.c:891 [inline]
reiserfs_xattr_init+0x57f/0xbb0 fs/reiserfs/xattr.c:1007
reiserfs_fill_super+0x2139/0x3150 fs/reiserfs/super.c:2175
mount_bdev+0x1f3/0x350 fs/super.c:1424
legacy_get_tree+0x109/0x220 fs/fs_context.c:611
vfs_get_tree+0x88/0x350 fs/super.c:1547
do_new_mount fs/namespace.c:3335 [inline]
path_mount+0x1492/0x1ed0 fs/namespace.c:3662
do_mount fs/namespace.c:3675 [inline]
__do_sys_mount fs/namespace.c:3884 [inline]
__se_sys_mount fs/namespace.c:3861 [inline]
__x64_sys_mount+0x293/0x310 fs/namespace.c:3861
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fd34067e1ea
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 00 00 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd341343ee8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd341343f80 RCX: 00007fd34067e1ea
RDX: 0000000020001100 RSI: 0000000020000040 RDI: 00007fd341343f40
RBP: 0000000020001100 R08: 00007fd341343f80 R09: 0000000000000080
R10: 0000000000000080 R11: 0000000000000246 R12: 0000000020000040
R13: 00007fd341343f40 R14: 00000000000010f6 R15: 00000000200000c0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:cpuacct_charge+0x194/0x3e0 kernel/sched/cpuacct.c:342
Code: 85 ed 0f 84 89 00 00 00 49 bc 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 4c 01 e2 48 8d bd 18 01 00 00 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 99 01 00 00 48 8b 9d 18 01 00 00 49 83 fd 07
RSP: 0018:ffffc90004d86ba0 EFLAGS: 00010006

RAX: 0000000020008027 RBX: ffff8880b980ff01 RCX: 0000000000000001
RDX: fffffbfff1876d40 RSI: ffffffff8a6c9c60 RDI: 0000000100040138
RBP: 0000000100040020 R08: 0000000000000000 R09: fffffbfff1d5a29a
R10: ffffffff8ead14d7 R11: 0000000000000800 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff8c3b6a00 R15: 000000000046b680
FS: 00007fd3413446c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000000ff01 CR3: 000000007db2c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

----------------
Code disassembly (best guess):

0: 85 ed test %ebp,%ebp
2: 0f 84 89 00 00 00 je 0x91
8: 49 bc 00 00 00 00 00 movabs $0xdffffc0000000000,%r12
f: fc ff df
12: 4c 89 f2 mov %r14,%rdx
15: 48 c1 ea 03 shr $0x3,%rdx
19: 4c 01 e2 add %r12,%rdx
1c: 48 8d bd 18 01 00 00 lea 0x118(%rbp),%rdi
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
2f: 0f 85 99 01 00 00 jne 0x1ce
35: 48 8b 9d 18 01 00 00 mov 0x118(%rbp),%rbx
3c: 49 83 fd 07 cmp $0x7,%r13


Tested on:

commit: 71cd4fc4 Add linux-next specific files for 20230808
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=17e1ad53a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=e36b5ba725f7349d
dashboard link: https://syzkaller.appspot.com/bug?extid=5671b8bcd5178fe56c23
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=1525213da80000

[Hillf Danton]

On Sun, 13 Aug 2023 00:24:12 -0700

> HEAD commit: 71cd4fc492ec Add linux-next specific files for 20230808
> git tree: linux-next

--- x/kernel/sched/cpuacct.c
+++ y/kernel/sched/cpuacct.c
@@ -338,8 +338,11 @@ void cpuacct_charge(struct task_struct *

lockdep_assert_rq_held(cpu_rq(cpu));

+ rcu_read_lock();
for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
*per_cpu_ptr(ca->cpuusage, cpu) += cputime;
+
+ rcu_read_unlock();
}

/*
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

BUG: unable to handle kernel paging request in corrupted

BUG: unable to handle page fault for address: 000000000000ff01
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 68064067 P4D 68064067 PUD 6806d067 PMD 0
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5037 Comm: kworker/1:3 Not tainted 6.5.0-rc5-next-20230808-syzkaller-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

Workqueue: 0x0 (events)
RIP: 0010:0xff01
Code: Unable to access opcode bytes at 0xfed7.
RSP: 0018:ffffc90003b2fc60 EFLAGS: 00010086
RAX: ffff888024685940 RBX: 000000000000ff01 RCX: 0000000000000000
RDX: ffff888021963b80 RSI: ffffffff812d721d RDI: 0000000000000007
RBP: 0000000100040020 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000100040020
R13: 000000000000ff01 R14: 0000000100040020 R15: 000000000000ff01
FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000000000000ff01 CR3: 000000001ef98000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>

</TASK>
Modules linked in:
CR2: 000000000000ff01

---[ end trace 0000000000000000 ]---

RIP: 0010:0xff01
Code: Unable to access opcode bytes at 0xfed7.
RSP: 0018:ffffc90003b2fc60 EFLAGS: 00010086

RAX: ffff888024685940 RBX: 000000000000ff01 RCX: 0000000000000000
RDX: ffff888021963b80 RSI: ffffffff812d721d RDI: 0000000000000007
RBP: 0000000100040020 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000100040020
R13: 000000000000ff01 R14: 0000000100040020 R15: 000000000000ff01
FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000000000000ff01 CR3: 000000001ef98000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Tested on:

commit: 71cd4fc4 Add linux-next specific files for 20230808
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

console output: https://syzkaller.appspot.com/x/log.txt?x=166b9763a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=e36b5ba725f7349d
dashboard link: https://syzkaller.appspot.com/bug?extid=5671b8bcd5178fe56c23
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=10060e27a80000

[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.