[syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    ce7f1a983b07 Add linux-next specific files for 20250923
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=118724e2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1be6fa3d47bce66e
dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1376e27c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=136e78e2580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c30be6f36c31/disk-ce7f1a98.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ae9ea347d4d8/vmlinux-ce7f1a98.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d59682a4f33c/bzImage-ce7f1a98.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+12479ae15958fc3f54ec@syzkaller.appspotmail.com

BUG: sleeping function called from invalid context at fs/inode.c:1928
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6028, name: syz.0.17
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
2 locks held by syz.0.17/6028:
 #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffff8880326bc998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #1: ffff8880326bc998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: hook_sb_delete+0xae/0xbd0 security/landlock/fs.c:1405
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 0 UID: 0 PID: 6028 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 __might_resched+0x495/0x610 kernel/sched/core.c:8960
 iput+0x2b/0xc50 fs/inode.c:1928
 hook_sb_delete+0x6b5/0xbd0 security/landlock/fs.c:1468
 security_sb_delete+0x80/0x150 security/security.c:1467
 generic_shutdown_super+0xaa/0x2c0 fs/super.c:634
 kill_anon_super fs/super.c:1281 [inline]
 kill_litter_super+0x76/0xb0 fs/super.c:1291
 deactivate_locked_super+0xbc/0x130 fs/super.c:473
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc08e18eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcd5efff18 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fc08e3e5fa0 RCX: 00007fc08e18eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000002c0
RBP: 00007fc08e211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc08e3e5fa0 R14: 00007fc08e3e5fa0 R15: 0000000000000002
 </TASK>


---
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 syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
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If the report is already addressed, 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 overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

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

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

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[Hillf Danton]

> Date: Tue, 23 Sep 2025 15:59:37 -0700	[thread overview]
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    ce7f1a983b07 Add linux-next specific files for 20250923
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=118724e2580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=1be6fa3d47bce66e
> dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
> compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1376e27c580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=136e78e2580000

#syz test

--- x/security/landlock/fs.c
+++ y/security/landlock/fs.c
@@ -1434,8 +1434,6 @@ static void hook_sb_delete(struct super_
 			spin_unlock(&inode->i_lock);
 			continue;
 		}
-		/* Keeps a reference to this inode until the next loop walk. */
-		__iget(inode);
 		spin_unlock(&inode->i_lock);
 
 		/*
@@ -1457,15 +1455,6 @@ static void hook_sb_delete(struct super_
 			 * It is therefore not necessary to lock inode->i_lock.
 			 */
 			rcu_assign_pointer(landlock_inode(inode)->object, NULL);
-			/*
-			 * At this point, we own the ihold() reference that was
-			 * originally set up by get_inode_object() and the
-			 * __iget() reference that we just set in this loop
-			 * walk.  Therefore the following call to iput() will
-			 * not sleep nor drop the inode because there is now at
-			 * least two references to it.
-			 */
-			iput(inode);
 		} else {
 			spin_unlock(&object->lock);
 			rcu_read_unlock();
@@ -1479,12 +1468,7 @@ static void hook_sb_delete(struct super_
 			 * disappear from under us until the next loop walk.
 			 */
 			spin_unlock(&sb->s_inode_list_lock);
-			/*
-			 * We can now actually put the inode reference from the
-			 * previous loop walk, which is not needed anymore.
-			 */
 			iput(prev_inode);
-			cond_resched();
 			spin_lock(&sb->s_inode_list_lock);
 		}
 		prev_inode = inode;
--

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+12479ae15958fc3f54ec@syzkaller.appspotmail.com
Tested-by: syzbot+12479ae15958fc3f54ec@syzkaller.appspotmail.com

Tested on:

commit:         ce7f1a98 Add linux-next specific files for 20250923
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13182142580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1be6fa3d47bce66e
dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=108c8f12580000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[Edward Adam Davis]

#syz test

diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index 4ed997f4a663..a18d53507210 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -1484,7 +1484,6 @@ static void hook_sb_delete(struct super_block *const sb)
 			 * previous loop walk, which is not needed anymore.
 			 */
 			iput(prev_inode);
-			cond_resched();
 			spin_lock(&sb->s_inode_list_lock);
 		}
 		prev_inode = inode;

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[Edward Adam Davis]

#syz test

diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index 4ed997f4a663..a18d53507210 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -1484,7 +1484,6 @@ static void hook_sb_delete(struct super_block *const sb)
 			 * previous loop walk, which is not needed anymore.
 			 */
 			iput(prev_inode);
-			cond_resched();
 			spin_lock(&sb->s_inode_list_lock);
 		}
 		prev_inode = inode;
diff --git a/kernel/fork.c b/kernel/fork.c
index e9a7fb5c3e49..a0b8eeeb1d27 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2349,7 +2349,7 @@ __latent_entropy struct task_struct *copy_process(
 	if (need_futex_hash_allocate_default(clone_flags)) {
 		retval = futex_hash_allocate_default();
 		if (retval)
-			goto bad_fork_core_free;
+			goto bad_fork_cancel_cgroup;
 		/*
 		 * If we fail beyond this point we don't free the allocated
 		 * futex hash map. We assume that another thread will be created

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: sleeping function called from invalid context in hook_sb_delete

BUG: sleeping function called from invalid context at fs/inode.c:1928
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6514, name: syz.0.17
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
2 locks held by syz.0.17/6514:
 #0: ffff8880306a20e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff8880306a20e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff8880306a20e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffff8880306a2998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #1: ffff8880306a2998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: hook_sb_delete+0xae/0xbc0 security/landlock/fs.c:1405
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 1 UID: 0 PID: 6514 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 __might_resched+0x495/0x610 kernel/sched/core.c:8960
 iput+0x2b/0xc50 fs/inode.c:1928
 hook_sb_delete+0x6b7/0xbc0 security/landlock/fs.c:1468
 security_sb_delete+0x80/0x150 security/security.c:1467
 generic_shutdown_super+0xaa/0x2c0 fs/super.c:634
 kill_anon_super fs/super.c:1281 [inline]
 kill_litter_super+0x76/0xb0 fs/super.c:1291
 deactivate_locked_super+0xbc/0x130 fs/super.c:473
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe6d878eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe6d961c038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fe6d89e5fa0 RCX: 00007fe6d878eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000002c0
RBP: 00007fe6d8811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe6d89e6038 R14: 00007fe6d89e5fa0 R15: 00007ffc5011e858
 </TASK>


Tested on:

commit:         ce7f1a98 Add linux-next specific files for 20250923
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=128f94e2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1be6fa3d47bce66e
dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14e2cce2580000

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[Edward Adam Davis]

#syz test: none

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

> #syz test: none

want either no args or 2 args (repo, branch), got 1

>

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

> #syz test: none

"none" does not look like a valid git repo address.

>
> -- 
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> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com.
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Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[Jan Kara]

Hello!

Added Landlock guys to CC since this is a bug in Landlock.

On Tue 23-09-25 15:59:37, syzbot wrote:
> syzbot found the following issue on:
> 
> HEAD commit:    ce7f1a983b07 Add linux-next specific files for 20250923
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=118724e2580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=1be6fa3d47bce66e
> dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
> compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1376e27c580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=136e78e2580000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/c30be6f36c31/disk-ce7f1a98.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/ae9ea347d4d8/vmlinux-ce7f1a98.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/d59682a4f33c/bzImage-ce7f1a98.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+12479ae15958fc3f54ec@syzkaller.appspotmail.com
> 
> BUG: sleeping function called from invalid context at fs/inode.c:1928

The first catch from the new might_sleep() annotations in iput().

> in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6028, name: syz.0.17
> preempt_count: 1, expected: 0
> RCU nest depth: 0, expected: 0
> 2 locks held by syz.0.17/6028:
>  #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
>  #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
>  #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
>  #1: ffff8880326bc998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
>  #1: ffff8880326bc998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: hook_sb_delete+0xae/0xbd0 security/landlock/fs.c:1405
> Preemption disabled at:
> [<0000000000000000>] 0x0
> CPU: 0 UID: 0 PID: 6028 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
>  __might_resched+0x495/0x610 kernel/sched/core.c:8960
>  iput+0x2b/0xc50 fs/inode.c:1928
>  hook_sb_delete+0x6b5/0xbd0 security/landlock/fs.c:1468

Indeed looks like a bug because we can call iput() while holding
sb->s_inode_list_lock in one case in hook_sb_delete().

								Honza

>  security_sb_delete+0x80/0x150 security/security.c:1467
>  generic_shutdown_super+0xaa/0x2c0 fs/super.c:634
>  kill_anon_super fs/super.c:1281 [inline]
>  kill_litter_super+0x76/0xb0 fs/super.c:1291
>  deactivate_locked_super+0xbc/0x130 fs/super.c:473
>  cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327
>  task_work_run+0x1d4/0x260 kernel/task_work.c:227
>  resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
>  exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
>  exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
>  syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
>  syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
>  do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fc08e18eec9
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffcd5efff18 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
> RAX: 0000000000000000 RBX: 00007fc08e3e5fa0 RCX: 00007fc08e18eec9
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000002c0
> RBP: 00007fc08e211f91 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fc08e3e5fa0 R14: 00007fc08e3e5fa0 R15: 0000000000000002
>  </TASK>
> 
> 
> ---
> 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 syzkaller@googlegroups.com.
> 
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> 
> If the report is already addressed, 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 overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
> 
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
> 
> If you want to undo deduplication, reply with:
> #syz undup
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: sleeping function called from invalid context in hook_sb_delete

BUG: sleeping function called from invalid context at fs/inode.c:1928
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6483, name: syz.0.17
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
2 locks held by syz.0.17/6483:
 #0: ffff888028f400e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
 #0: ffff888028f400e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
 #0: ffff888028f400e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
 #1: ffff888028f40998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #1: ffff888028f40998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: hook_sb_delete+0xae/0xbc0 security/landlock/fs.c:1405
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 0 UID: 0 PID: 6483 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 __might_resched+0x495/0x610 kernel/sched/core.c:8960
 iput+0x2b/0xc50 fs/inode.c:1928
 hook_sb_delete+0x6b7/0xbc0 security/landlock/fs.c:1468
 security_sb_delete+0x80/0x150 security/security.c:1467
 generic_shutdown_super+0xaa/0x2c0 fs/super.c:634
 kill_anon_super fs/super.c:1281 [inline]
 kill_litter_super+0x76/0xb0 fs/super.c:1291
 deactivate_locked_super+0xbc/0x130 fs/super.c:473
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1327
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8b7e78eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8b7f714038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f8b7e9e5fa0 RCX: 00007f8b7e78eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000002c0
RBP: 00007f8b7e811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8b7e9e6038 R14: 00007f8b7e9e5fa0 R15: 00007ffe75b4a848
 </TASK>


Tested on:

commit:         ce7f1a98 Add linux-next specific files for 20250923
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13644f12580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1be6fa3d47bce66e
dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11724d34580000

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[Christian Brauner]

On Wed, Sep 24, 2025 at 01:05:03PM +0200, Jan Kara wrote:
> Hello!
> 
> Added Landlock guys to CC since this is a bug in Landlock.
> 
> On Tue 23-09-25 15:59:37, syzbot wrote:
> > syzbot found the following issue on:
> > 
> > HEAD commit:    ce7f1a983b07 Add linux-next specific files for 20250923
> > git tree:       linux-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=118724e2580000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=1be6fa3d47bce66e
> > dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
> > compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1376e27c580000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=136e78e2580000
> > 
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/c30be6f36c31/disk-ce7f1a98.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/ae9ea347d4d8/vmlinux-ce7f1a98.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/d59682a4f33c/bzImage-ce7f1a98.xz
> > 
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+12479ae15958fc3f54ec@syzkaller.appspotmail.com
> > 
> > BUG: sleeping function called from invalid context at fs/inode.c:1928
> 
> The first catch from the new might_sleep() annotations in iput().
> 
> > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 6028, name: syz.0.17
> > preempt_count: 1, expected: 0
> > RCU nest depth: 0, expected: 0
> > 2 locks held by syz.0.17/6028:
> >  #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
> >  #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
> >  #0: ffff8880326bc0e0 (&type->s_umount_key#48){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
> >  #1: ffff8880326bc998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
> >  #1: ffff8880326bc998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: hook_sb_delete+0xae/0xbd0 security/landlock/fs.c:1405
> > Preemption disabled at:
> > [<0000000000000000>] 0x0
> > CPU: 0 UID: 0 PID: 6028 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
> > Call Trace:
> >  <TASK>
> >  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
> >  __might_resched+0x495/0x610 kernel/sched/core.c:8960
> >  iput+0x2b/0xc50 fs/inode.c:1928
> >  hook_sb_delete+0x6b5/0xbd0 security/landlock/fs.c:1468
> 
> Indeed looks like a bug because we can call iput() while holding
> sb->s_inode_list_lock in one case in hook_sb_delete().

Very nice that the annotations help finding this!

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

syzbot has bisected this issue to:

commit 2ef435a872abc347dc0a92f1c213bb0af3cbf195
Author: Max Kellermann <max.kellermann@ionos.com>
Date:   Wed Sep 17 15:36:31 2025 +0000

    fs: add might_sleep() annotation to iput() and more

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1092ba7c580000
start commit:   7c3ba4249a36 Add linux-next specific files for 20251008
git tree:       linux-next
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1292ba7c580000
console output: https://syzkaller.appspot.com/x/log.txt?x=1492ba7c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fa7a95b14b1eaa
dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12280dcd980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=111d852f980000

Reported-by: syzbot+12479ae15958fc3f54ec@syzkaller.appspotmail.com
Fixes: 2ef435a872ab ("fs: add might_sleep() annotation to iput() and more")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

Hello,

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

Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
------------[ cut here ]------------
WARNING: kernel/printk/printk_ringbuffer.c:1278 at get_data+0x48a/0x840 kernel/printk/printk_ringbuffer.c:1278, CPU#1: kworker/u9:1/5147
Modules linked in:
CPU: 1 UID: 0 PID: 5147 Comm: kworker/u9:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: hci0 hci_rx_work
RIP: 0010:get_data+0x48a/0x840 kernel/printk/printk_ringbuffer.c:1278
Code: 83 c4 f8 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 07 84 c0 0f 85 ee 01 00 00 44 89 65 00 49 83 c5 08 eb 13 e8 b7 d6 1e 00 90 <0f> 0b 90 eb 05 e8 ac d6 1e 00 45 31 ed 4c 89 e8 48 83 c4 28 5b 41
RSP: 0018:ffffc9000ed9eec0 EFLAGS: 00010293
RAX: ffffffff81a1ef09 RBX: 00003fffffffffff RCX: ffff888035008000
RDX: 0000000000000000 RSI: 00003fffffffffff RDI: 0000000000000000
RBP: 0000000000000012 R08: 0000000000000ea9 R09: 0000005832e2457e
R10: 0000005832e2457e R11: 0000141b82000035 R12: 0000000000000012
R13: 0000000000000000 R14: ffffc9000ed9f008 R15: 1ffffffff1c0ab06
FS:  0000000000000000(0000) GS:ffff888125dd3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffea26700c0 CR3: 0000000075b8a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 copy_data kernel/printk/printk_ringbuffer.c:1857 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1966 [inline]
 _prb_read_valid+0x672/0xa90 kernel/printk/printk_ringbuffer.c:2143
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2215
 printk_get_next_message+0x15c/0x7b0 kernel/printk/printk.c:2978
 console_emit_next_record kernel/printk/printk.c:3062 [inline]
 console_flush_one_record kernel/printk/printk.c:3194 [inline]
 console_flush_all+0x4cc/0xb10 kernel/printk/printk.c:3268
 __console_flush_and_unlock kernel/printk/printk.c:3298 [inline]
 console_unlock+0xbb/0x190 kernel/printk/printk.c:3338
 vprintk_emit+0x4c5/0x590 kernel/printk/printk.c:2423
 _printk+0xcf/0x120 kernel/printk/printk.c:2448
 bt_warn+0x10b/0x160 net/bluetooth/lib.c:276
 hci_cc_func net/bluetooth/hci_event.c:4192 [inline]
 hci_cmd_complete_evt+0x493/0xa80 net/bluetooth/hci_event.c:4216
 hci_event_func net/bluetooth/hci_event.c:7629 [inline]
 hci_event_packet+0x78f/0x1260 net/bluetooth/hci_event.c:7686
 hci_rx_work+0x45d/0xfc0 net/bluetooth/hci_core.c:4099
 process_one_work+0x94a/0x15d0 kernel/workqueue.c:3267
 process_scheduled_works kernel/workqueue.c:3350 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3431
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


Tested on:

commit:         98bd8b16 Add linux-next specific files for 20251031
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12a8e32f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=90be0b22166ec0b9
dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1430e32f980000

Re: [syzbot] [fs?] BUG: sleeping function called from invalid context in hook_sb_delete

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

f
[  104.167925][ T5820]  ? clear_bhb_loop+0x60/0xb0
[  104.167948][ T5820]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  104.167967][ T5820] RIP: 0033:0x7f9a9fef16c5
[  104.167983][ T5820] Code: Unable to access opcode bytes at 0x7f9a9fef169b.
[  104.167993][ T5820] RSP: 002b:00007fff0fc3e0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[  104.168021][ T5820] RAX: ffffffffffffffda RBX: 00005583ec761b10 RCX: 00007f9a9fef16c5
[  104.168036][ T5820] RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
[  104.168048][ T5820] RBP: 00005583ec738910 R08: 0000000000000000 R09: 0000000000000000
[  104.168060][ T5820] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[  104.168071][ T5820] R13: 00007fff0fc3e140 R14: 0000000000000000 R15: 0000000000000000
[  104.168101][ T5820]  </TASK>
2025/11/05 20:54:56 parsed 1 programs
[  105.509351][ T5829] BUG: sleeping function called from invalid context at fs/inode.c:1920
[  105.518601][ T5829] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5829, name: syz-execprog
[  105.528439][ T5829] preempt_count: 1, expected: 0
[  105.533521][ T5829] RCU nest depth: 0, expected: 0
[  105.538811][ T5829] 1 lock held by syz-execprog/5829:
[  105.544194][ T5829]  #0: ffff88807e6f68d8 (&sb->s_type->i_lock_key#9){+.+.}-{3:3}, at: iput+0x2db/0x1050
[  105.554222][ T5829] Preemption disabled at:
[  105.554232][ T5829] [<0000000000000000>] 0x0
[  105.564065][ T5829] CPU: 0 UID: 0 PID: 5829 Comm: syz-execprog Tainted: G        W           syzkaller #0 PREEMPT(full) 
[  105.564091][ T5829] Tainted: [W]=WARN
[  105.564096][ T5829] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
[  105.564105][ T5829] Call Trace:
[  105.564114][ T5829]  <TASK>
[  105.564121][ T5829]  dump_stack_lvl+0x189/0x250
[  105.564144][ T5829]  ? __pfx_dump_stack_lvl+0x10/0x10
[  105.564160][ T5829]  ? __pfx__printk+0x10/0x10
[  105.564176][ T5829]  ? call_rcu+0x6ff/0x9c0
[  105.564197][ T5829]  ? print_lock_name+0xde/0x100
[  105.564218][ T5829]  __might_resched+0x495/0x610
[  105.564241][ T5829]  ? __pfx___might_resched+0x10/0x10
[  105.564258][ T5829]  ? do_raw_spin_lock+0x121/0x290
[  105.564286][ T5829]  ? __pfx_do_raw_spin_lock+0x10/0x10
[  105.564320][ T5829]  iput+0x741/0x1050
[  105.564352][ T5829]  __dentry_kill+0x209/0x660
[  105.564371][ T5829]  ? dput+0x37/0x2b0
[  105.564389][ T5829]  dput+0x19f/0x2b0
[  105.564406][ T5829]  __fput+0x68e/0xa70
[  105.564431][ T5829]  fput_close_sync+0x113/0x220
[  105.564450][ T5829]  ? __pfx_fput_close_sync+0x10/0x10
[  105.564470][ T5829]  ? do_raw_spin_unlock+0x122/0x240
[  105.564495][ T5829]  __x64_sys_close+0x7f/0x110
[  105.564517][ T5829]  do_syscall_64+0xfa/0xfa0
[  105.564541][ T5829]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  105.564558][ T5829]  ? clear_bhb_loop+0x60/0xb0
[  105.564577][ T5829]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  105.564593][ T5829] RIP: 0033:0x40dd0e
[  105.564610][ T5829] Code: 24 28 44 8b 44 24 2c e9 70 ff ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 49 89 f2 48 89 fa 48 89 ce 48 89 df 0f 05 <48> 3d 01 f0 ff ff 76 15 48 f7 d8 48 89 c1 48 c7 c0 ff ff ff ff 48
[  105.564625][ T5829] RSP: 002b:000000c002db1760 EFLAGS: 00000212 ORIG_RAX: 0000000000000003
[  105.564688][ T5829] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000040dd0e
[  105.564701][ T5829] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
[  105.564711][ T5829] RBP: 000000c002db17a0 R08: 0000000000000000 R09: 0000000000000000
[  105.564723][ T5829] R10: 0000000000000000 R11: 0000000000000212 R12: 000000c002db18c0
[  105.564735][ T5829] R13: 00000000000007ff R14: 000000c000002380 R15: 000000c0008937c0
[  105.564765][ T5829]  </TASK>
[  107.337546][ T5837] BUG: sleeping function called from invalid context at fs/inode.c:1920
[  107.347227][ T5837] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5837, name: dhcpcd
[  107.356267][ T5837] preempt_count: 1, expected: 0
[  107.361915][ T5837] RCU nest depth: 0, expected: 0
[  107.367125][ T5837] 1 lock held by dhcpcd/5837:
[  107.373083][ T5837]  #0: ffff88807e6fa3d8 (&sb->s_type->i_lock_key#9){+.+.}-{3:3}, at: iput+0x2db/0x1050
[  107.384068][ T5837] Preemption disabled at:
[  107.384082][ T5837] [<0000000000000000>] 0x0
[  107.393377][ T5837] CPU: 1 UID: 0 PID: 5837 Comm: dhcpcd Tainted: G        W           syzkaller #0 PREEMPT(full) 
[  107.393403][ T5837] Tainted: [W]=WARN
[  107.393408][ T5837] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
[  107.393417][ T5837] Call Trace:
[  107.393424][ T5837]  <TASK>
[  107.393430][ T5837]  dump_stack_lvl+0x189/0x250
[  107.393456][ T5837]  ? __pfx_dump_stack_lvl+0x10/0x10
[  107.393480][ T5837]  ? __pfx__printk+0x10/0x10
[  107.393503][ T5837]  ? print_lock_name+0xde/0x100
[  107.393526][ T5837]  __might_resched+0x495/0x610
[  107.393553][ T5837]  ? __pfx___might_resched+0x10/0x10
[  107.393570][ T5837]  ? do_raw_spin_lock+0x121/0x290
[  107.393597][ T5837]  ? __pfx_do_raw_spin_lock+0x10/0x10
[  107.393632][ T5837]  iput+0x741/0x1050
[  107.393662][ T5837]  __dentry_kill+0x209/0x660
[  107.393681][ T5837]  ? dput+0x37/0x2b0
[  107.393699][ T5837]  dput+0x19f/0x2b0
[  107.393717][ T5837]  __fput+0x68e/0xa70
[  107.393749][ T5837]  fput_close_sync+0x113/0x220
[  107.393768][ T5837]  ? __pfx_fput_close_sync+0x10/0x10
[  107.393790][ T5837]  ? do_raw_spin_unlock+0x122/0x240
[  107.393819][ T5837]  __x64_sys_close+0x7f/0x110
[  107.393843][ T5837]  do_syscall_64+0xfa/0xfa0
[  107.393871][ T5837]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  107.393890][ T5837]  ? clear_bhb_loop+0x60/0xb0
[  107.393915][ T5837]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  107.393933][ T5837] RIP: 0033:0x7fc58c16c407
[  107.393950][ T5837] Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
[  107.393968][ T5837] RSP: 002b:00007ffc1197cc80 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
[  107.393988][ T5837] RAX: ffffffffffffffda RBX: 00007fc58c0e2740 RCX: 00007fc58c16c407
[  107.394002][ T5837] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
[  107.394014][ T5837] RBP: 000055fc7ab074b0 R08: 0000000000000000 R09: 0000000000000000
[  107.394026][ T5837] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
[  107.394038][ T5837] R13: 000055fc83902290 R14: 0000000000000000 R15: 000055fc7ab1cac0
[  107.394071][ T5837]  </TASK>
[  108.750656][ T5835] cgroup: Unknown subsys name 'net'
[  108.759273][ T5835] BUG: sleeping function called from invalid context at fs/inode.c:1920
[  108.769492][ T5835] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5835, name: syz-executor
[  108.782190][ T5835] preempt_count: 1, expected: 0
[  108.787683][ T5835] RCU nest depth: 0, expected: 0
[  108.792976][ T5835] 2 locks held by syz-executor/5835:
[  108.799370][ T5835]  #0: ffff8880340e80e0 (&type->s_umount_key#44){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0
[  108.811870][ T5835]  #1: ffff888077e41970 (&sb->s_type->i_lock_key#33){+.+.}-{3:3}, at: iput+0x2db/0x1050
[  108.822811][ T5835] Preemption disabled at:
[  108.822824][ T5835] [<0000000000000000>] 0x0
[  108.833460][ T5835] CPU: 1 UID: 0 PID: 5835 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(full) 
[  108.833488][ T5835] Tainted: [W]=WARN
[  108.833493][ T5835] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
[  108.833502][ T5835] Call Trace:
[  108.833508][ T5835]  <TASK>
[  108.833515][ T5835]  dump_stack_lvl+0x189/0x250
[  108.833542][ T5835]  ? __pfx_dump_stack_lvl+0x10/0x10
[  108.833561][ T5835]  ? __pfx__printk+0x10/0x10
[  108.833580][ T5835]  ? print_lock_name+0xde/0x100
[  108.833601][ T5835]  __might_resched+0x495/0x610
[  108.833625][ T5835]  ? __pfx___might_resched+0x10/0x10
[  108.833642][ T5835]  ? do_raw_spin_lock+0x121/0x290
[  108.833666][ T5835]  ? __pfx_do_raw_spin_lock+0x10/0x10
[  108.833699][ T5835]  iput+0x741/0x1050
[  108.833731][ T5835]  __dentry_kill+0x209/0x660
[  108.833751][ T5835]  ? dput+0x37/0x2b0
[  108.833770][ T5835]  dput+0x19f/0x2b0
[  108.833789][ T5835]  shrink_dcache_for_umount+0xa0/0x170
[  108.833815][ T5835]  generic_shutdown_super+0x67/0x2c0
[  108.833843][ T5835]  kill_anon_super+0x3b/0x70
[  108.833868][ T5835]  kernfs_kill_sb+0x161/0x180
[  108.833895][ T5835]  deactivate_locked_super+0xbc/0x130
[  108.833920][ T5835]  cleanup_mnt+0x425/0x4c0
[  108.833943][ T5835]  ? lockdep_hardirqs_on+0x9c/0x150
[  108.833970][ T5835]  task_work_run+0x1d4/0x260
[  108.833998][ T5835]  ? __pfx_task_work_run+0x10/0x10
[  108.834027][ T5835]  ? exit_to_user_mode_loop+0x55/0x4f0
[  108.834058][ T5835]  exit_to_user_mode_loop+0xff/0x4f0
[  108.834084][ T5835]  ? rcu_is_watching+0x15/0xb0
[  108.834109][ T5835]  do_syscall_64+0x2e9/0xfa0
[  108.834135][ T5835]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  108.834152][ T5835]  ? clear_bhb_loop+0x60/0xb0
[  108.834175][ T5835]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  108.834192][ T5835] RIP: 0033:0x7f2c235901f7
[  108.834208][ T5835] Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
[  108.834224][ T5835] RSP: 002b:00007ffeee90f4f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
[  108.834244][ T5835] RAX: 0000000000000000 RBX: 00007ffeee90f5f0 RCX: 00007f2c235901f7
[  108.834256][ T5835] RDX: 00007f2c23623d15 RSI: 0000000000000000 RDI: 00007f2c236125ca
[  108.834266][ T5835] RBP: 00007f2c236125ca R08: 00007f2c236128ae R09: 0000000000000000
[  108.834277][ T5835] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2c23612844
[  108.834287][ T5835] R13: 00007f2c23623d15 R14: 00007ffeee90f608 R15: 00007ffeee90f500
[  108.834313][ T5835]  </TASK>
[  109.214905][ T5835] cgroup: Unknown subsys name 'cpuset'
[  109.226104][ T5835] cgroup: Unknown subsys name 'rlimit'
[  110.666383][ T5835] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[  110.845546][ T5195] BUG: sleeping function called from invalid context at fs/inode.c:1920
[  110.854984][ T5195] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5195, name: udevd
[  110.865089][ T5195] preempt_count: 1, expected: 0
[  110.870130][ T5195] RCU nest depth: 0, expected: 0
[  110.875858][ T5195] 2 locks held by udevd/5195:
[  110.881834][ T5195]  #0: ffff88802feb6420 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
[  110.893073][ T5195]  #1: ffff8880306928e8 (&sb->s_type->i_lock_key){+.+.}-{3:3}, at: iput+0x2db/0x1050
[  110.903490][ T5195] Preemption disabled at:
[  110.903505][ T5195] [<0000000000000000>] 0x0
[  110.912829][ T5195] CPU: 1 UID: 0 PID: 5195 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(full) 
[  110.912861][ T5195] Tainted: [W]=WARN
[  110.912867][ T5195] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
[  110.912878][ T5195] Call Trace:
[  110.912886][ T5195]  <TASK>
[  110.912894][ T5195]  dump_stack_lvl+0x189/0x250
[  110.912924][ T5195]  ? __pfx_dump_stack_lvl+0x10/0x10
[  110.912946][ T5195]  ? __pfx__printk+0x10/0x10
[  110.912969][ T5195]  ? print_lock_name+0xde/0x100
[  110.912994][ T5195]  __might_resched+0x495/0x610
[  110.913020][ T5195]  ? __pfx___might_resched+0x10/0x10
[  110.913036][ T5195]  ? do_raw_spin_lock+0x121/0x290
[  110.913063][ T5195]  ? __pfx_do_raw_spin_lock+0x10/0x10
[  110.913095][ T5195]  iput+0x741/0x1050
[  110.913122][ T5195]  do_unlinkat+0x39f/0x560
[  110.913155][ T5195]  ? __pfx_do_unlinkat+0x10/0x10
[  110.913182][ T5195]  ? strncpy_from_user+0x150/0x2c0
[  110.913209][ T5195]  ? getname_flags+0x1e5/0x540
[  110.913232][ T5195]  __x64_sys_unlink+0x47/0x50
[  110.913267][ T5195]  do_syscall_64+0xfa/0xfa0
[  110.913295][ T5195]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  110.913313][ T5195]  ? clear_bhb_loop+0x60/0xb0
[  110.913335][ T5195]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  110.913354][ T5195] RIP: 0033:0x7f9a9ff15937
[  110.913371][ T5195] Code: 00 00 e9 a9 fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 5f 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 91 b4 0d 00 f7 d8 64 89 02 b8
[  110.913387][ T5195] RSP: 002b:00007fff0fc3e2a8 EFLAGS: 00000202 ORIG_RAX: 0000000000000057
[  110.913408][ T5195] RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f9a9ff15937
[  110.913422][ T5195] RDX: ffffffffffffffff RSI: 000000000000000b RDI: 00005583c5bc802e
[  110.913434][ T5195] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[  110.913445][ T5195] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
[  110.913456][ T5195] R13: 00005583c5be3100 R14: 0000000000000000 R15: 0000000000000000
[  110.913486][ T5195]  </TASK>


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2124321294=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.4'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 7e2882b3269
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=7e2882b32698b70f3149aee00c41e3d2d941dca3 -X github.com/google/syzkaller/prog.gitRevisionDate=20251007-152513"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=7e2882b32698b70f3149aee00c41e3d2d941dca3 -X github.com/google/syzkaller/prog.gitRevisionDate=20251007-152513"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=7e2882b32698b70f3149aee00c41e3d2d941dca3 -X github.com/google/syzkaller/prog.gitRevisionDate=20251007-152513"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"7e2882b32698b70f3149aee00c41e3d2d941dca3\"
/usr/bin/ld: /tmp/ccT2jI60.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x104): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=11651084580000


Tested on:

commit:         84d39fb9 Add linux-next specific files for 20251105
git tree:       linux-next
kernel config:  https://syzkaller.appspot.com/x/.config?x=bebc0cb9c2989b81
dashboard link: https://syzkaller.appspot.com/bug?extid=12479ae15958fc3f54ec
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=139f532f980000