======================================================
WARNING: possible circular locking dependency detected
5.10.109 #1 Not tainted
------------------------------------------------------
syz-executor.5/15713 is trying to acquire lock:
ffff888054d2ae58 (&sighand->siglock){....}-{2:2}, at: __lock_task_sighand+0xd3/0x2f0 kernel/signal.c:1391

but task is already holding lock:
ffff88800dd62578 (&tty->read_wait){....}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&tty->read_wait){....}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159
       __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122
       pty_flush_buffer+0x124/0x160 drivers/tty/pty.c:235
       tty_driver_flush_buffer+0x60/0x80 drivers/tty/tty_ioctl.c:95
       isig+0x1da/0x430 drivers/tty/n_tty.c:1137
       n_tty_receive_signal_char+0x1f/0x150 drivers/tty/n_tty.c:1238
       n_tty_receive_char_special+0x1255/0x2aa0 drivers/tty/n_tty.c:1284
       n_tty_receive_buf_fast drivers/tty/n_tty.c:1605 [inline]
       __receive_buf drivers/tty/n_tty.c:1639 [inline]
       n_tty_receive_buf_common+0x1e57/0x2b70 drivers/tty/n_tty.c:1737
       tiocsti drivers/tty/tty_io.c:2277 [inline]
       tty_ioctl+0x51b/0x1830 drivers/tty/tty_io.c:2658
       vfs_ioctl fs/ioctl.c:48 [inline]
       __do_sys_ioctl fs/ioctl.c:753 [inline]
       __se_sys_ioctl fs/ioctl.c:739 [inline]
       __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #1 (&tty->ctrl_lock){....}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159
       __proc_set_tty+0x2c/0x610 drivers/tty/tty_jobctrl.c:98
       proc_set_tty drivers/tty/tty_jobctrl.c:121 [inline]
       tiocsctty drivers/tty/tty_jobctrl.c:387 [inline]
       tty_jobctrl_ioctl+0x57e/0xe10 drivers/tty/tty_jobctrl.c:564
       tty_ioctl+0x1361/0x1830 drivers/tty/tty_io.c:2737
       vfs_ioctl fs/ioctl.c:48 [inline]
       __do_sys_ioctl fs/ioctl.c:753 [inline]
       __se_sys_ioctl fs/ioctl.c:739 [inline]
       __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #0 (&sighand->siglock){....}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:2986 [inline]
       check_prevs_add kernel/locking/lockdep.c:3111 [inline]
       validate_chain kernel/locking/lockdep.c:3726 [inline]
       __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4952
       lock_acquire kernel/locking/lockdep.c:5562 [inline]
       lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5527
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159
       __lock_task_sighand+0xd3/0x2f0 kernel/signal.c:1391
       lock_task_sighand include/linux/sched/signal.h:693 [inline]
       task_work_add+0x1db/0x2b0 kernel/task_work.c:58
       io_req_task_work_add fs/io_uring.c:2064 [inline]
       __io_async_wake+0x40b/0x8d0 fs/io_uring.c:4977
       __wake_up_common+0x14c/0x4c0 kernel/sched/wait.c:93
       __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123
       tty_ldisc_lock+0x40/0xb0 drivers/tty/tty_ldisc.c:335
       tty_set_ldisc+0x8e/0x670 drivers/tty/tty_ldisc.c:562
       tiocsetd drivers/tty/tty_io.c:2420 [inline]
       tty_ioctl+0x6cc/0x1830 drivers/tty/tty_io.c:2679
       vfs_ioctl fs/ioctl.c:48 [inline]
       __do_sys_ioctl fs/ioctl.c:753 [inline]
       __se_sys_ioctl fs/ioctl.c:739 [inline]
       __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

other info that might help us debug this:

Chain exists of:
  &sighand->siglock --> &tty->ctrl_lock --> &tty->read_wait

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&tty->read_wait);
                               lock(&tty->ctrl_lock);
                               lock(&tty->read_wait);
  lock(&sighand->siglock);

 *** DEADLOCK ***

3 locks held by syz-executor.5/15713:
 #0: ffff88800dd621c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:19
 #1: ffff88800dd62578 (&tty->read_wait){....}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122
 #2: ffffffff84df6fe0 (rcu_read_lock){....}-{1:2}, at: __lock_task_sighand+0x0/0x2f0 kernel/signal.c:1353

stack backtrace:
CPU: 0 PID: 15713 Comm: syz-executor.5 Not tainted 5.10.109 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:118
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2121
 check_prev_add kernel/locking/lockdep.c:2986 [inline]
 check_prevs_add kernel/locking/lockdep.c:3111 [inline]
 validate_chain kernel/locking/lockdep.c:3726 [inline]
 __lock_acquire+0x29e3/0x5b00 kernel/locking/lockdep.c:4952
 lock_acquire kernel/locking/lockdep.c:5562 [inline]
 lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5527
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159
 __lock_task_sighand+0xd3/0x2f0 kernel/signal.c:1391
 lock_task_sighand include/linux/sched/signal.h:693 [inline]
 task_work_add+0x1db/0x2b0 kernel/task_work.c:58
 io_req_task_work_add fs/io_uring.c:2064 [inline]
 __io_async_wake+0x40b/0x8d0 fs/io_uring.c:4977
 __wake_up_common+0x14c/0x4c0 kernel/sched/wait.c:93
 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123
 tty_ldisc_lock+0x40/0xb0 drivers/tty/tty_ldisc.c:335
 tty_set_ldisc+0x8e/0x670 drivers/tty/tty_ldisc.c:562
 tiocsetd drivers/tty/tty_io.c:2420 [inline]
 tty_ioctl+0x6cc/0x1830 drivers/tty/tty_io.c:2679
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f1fb3865b19
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1fb0ddb188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1fb3978f60 RCX: 00007f1fb3865b19
RDX: 0000000020000080 RSI: 0000000000005423 RDI: 0000000000000004
RBP: 00007f1fb38bff6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc0f0bdc8f R14: 00007f1fb0ddb300 R15: 0000000000022000
hpet: Lost 8 RTC interrupts
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 0
9pnet: Could not find request transport: 7ùöfdno=0x0000000000000003
CPU: 1 PID: 15725 Comm: syz-executor.7 Not tainted 5.10.109 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:118
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail.cold+0x5/0xa lib/fault-inject.c:146
 should_failslab+0x5/0x10 mm/slab_common.c:1193
 slab_pre_alloc_hook mm/slab.h:515 [inline]
 slab_alloc_node mm/slub.c:2821 [inline]
 slab_alloc mm/slub.c:2904 [inline]
 kmem_cache_alloc+0x5b/0x350 mm/slub.c:2909
 kmem_cache_zalloc include/linux/slab.h:654 [inline]
 __alloc_file+0x21/0x310 fs/file_table.c:101
 alloc_empty_file+0x6d/0x170 fs/file_table.c:151
 path_openat+0xde/0x26c0 fs/namei.c:3346
 do_filp_open+0x17e/0x3c0 fs/namei.c:3387
 do_sys_openat2+0x16d/0x420 fs/open.c:1180
 do_sys_open fs/open.c:1196 [inline]
 __do_sys_openat fs/open.c:1212 [inline]
 __se_sys_openat fs/open.c:1207 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1207
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fa893cc2a04
Code: 84 00 00 00 00 00 44 89 54 24 0c e8 96 f9 ff ff 44 8b 54 24 0c 44 89 e2 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 89 44 24 0c e8 c8 f9 ff ff 8b 44
RSP: 002b:00007fa891284ed0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa893d59970 RCX: 00007fa893cc2a04
RDX: 0000000000000002 RSI: 00007fa891285000 RDI: 00000000ffffff9c
RBP: 00007fa891285000 R08: 0000000000000000 R09: ffffffffffffffff
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000002
R13: 0000000000000005 R14: 0000000020000248 R15: 0000000000000003
audit: type=1326 audit(1654066132.171:121): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=15708 comm="syz-executor.5" exe="/syz-executor.5" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7f1fb3865b19 code=0x0