======================================================
WARNING: possible circular locking dependency detected
5.14.0-rc1-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/10500 is trying to acquire lock:
ffffffff8c7d6b20 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x30 mm/page_alloc.c:4210

but task is already holding lock:
ffff8880b9c4d0c8 (lock#2){-.-.}-{2:2}, at: local_lock_acquire+0x7/0x130 include/linux/local_lock_internal.h:41

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (lock#2){-.-.}-{2:2}:
       lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
       local_lock_acquire+0x23/0x130 include/linux/local_lock_internal.h:42
       free_unref_page+0x242/0x550 mm/page_alloc.c:3427
       mm_free_pgd kernel/fork.c:636 [inline]
       __mmdrop+0xae/0x3f0 kernel/fork.c:687
       mmdrop include/linux/sched/mm.h:49 [inline]
       finish_task_switch+0x221/0x630 kernel/sched/core.c:4582
       context_switch kernel/sched/core.c:4686 [inline]
       __schedule+0xc0f/0x11f0 kernel/sched/core.c:5940
       preempt_schedule_notrace+0x12c/0x170 kernel/sched/core.c:6179
       preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:36
       rcu_read_unlock_sched_notrace include/linux/rcupdate.h:809 [inline]
       trace_lock_release+0xa1/0x150 include/trace/events/lock.h:58
       lock_release+0x81/0x7b0 kernel/locking/lockdep.c:5636
       might_alloc include/linux/sched/mm.h:199 [inline]
       slab_pre_alloc_hook mm/slab.h:485 [inline]
       slab_alloc_node mm/slub.c:2902 [inline]
       slab_alloc mm/slub.c:2989 [inline]
       __kmalloc_track_caller+0x61/0x390 mm/slub.c:4650
       kmemdup+0x21/0x50 mm/util.c:128
       dev_exception_add+0x8f/0x490 security/device_cgroup.c:94
       devcgroup_update_access security/device_cgroup.c:734 [inline]
       devcgroup_access_write+0x1636/0x2870 security/device_cgroup.c:764
       cgroup_file_write+0x2b6/0x740 kernel/cgroup/cgroup.c:3814
       kernfs_fop_write_iter+0x3b6/0x510 fs/kernfs/file.c:296
       call_write_iter include/linux/fs.h:2114 [inline]
       new_sync_write fs/read_write.c:518 [inline]
       vfs_write+0xa39/0xc90 fs/read_write.c:605
       ksys_write+0x171/0x2a0 fs/read_write.c:658
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

-> #0 (fs_reclaim){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3051 [inline]
       check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174
       validate_chain kernel/locking/lockdep.c:3789 [inline]
       __lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015
       lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
       __fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4552
       fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4566
       prepare_alloc_pages+0x151/0x5a0 mm/page_alloc.c:5164
       __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5363
       stack_depot_save+0x361/0x490 lib/stackdepot.c:303
       save_stack+0xf9/0x1f0 mm/page_owner.c:120
       __set_page_owner+0x42/0x2f0 mm/page_owner.c:181
       prep_new_page mm/page_alloc.c:2433 [inline]
       __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5301
       alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline]
       vm_area_alloc_pages mm/vmalloc.c:2793 [inline]
       __vmalloc_area_node mm/vmalloc.c:2863 [inline]
       __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2966
       __vmalloc_node mm/vmalloc.c:3015 [inline]
       vzalloc+0x75/0x80 mm/vmalloc.c:3085
       n_tty_open+0x19/0x150 drivers/tty/n_tty.c:1848
       tty_ldisc_open drivers/tty/tty_ldisc.c:449 [inline]
       tty_ldisc_setup+0x1ba/0x3c0 drivers/tty/tty_ldisc.c:776
       tty_init_dev+0x271/0x4c0 drivers/tty/tty_io.c:1453
       ptmx_open+0xdb/0x2c0 drivers/tty/pty.c:834
       chrdev_open+0x53b/0x5f0 fs/char_dev.c:414
       do_dentry_open+0x7cb/0x1020 fs/open.c:826
       do_open fs/namei.c:3374 [inline]
       path_openat+0x27e7/0x36b0 fs/namei.c:3507
       do_filp_open+0x253/0x4d0 fs/namei.c:3534
       do_sys_openat2+0x124/0x460 fs/open.c:1204
       do_sys_open fs/open.c:1220 [inline]
       __do_sys_openat fs/open.c:1236 [inline]
       __se_sys_openat fs/open.c:1231 [inline]
       __x64_sys_openat+0x243/0x290 fs/open.c:1231
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x44/0xae

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(lock#2);
                               lock(fs_reclaim);
                               lock(lock#2);
  lock(fs_reclaim);

 *** DEADLOCK ***

4 locks held by syz-executor.4/10500:
 #0: ffffffff8cdd04e8 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcd/0x2c0 drivers/tty/pty.c:833
 #1: ffff8880831ad1c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_init_dev+0x6a/0x4c0 drivers/tty/tty_io.c:1428
 #2: ffff8880831ad098 (&tty->ldisc_sem){++++}-{0:0}, at: __tty_ldisc_lock drivers/tty/tty_ldisc.c:300 [inline]
 #2: ffff8880831ad098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_lock+0x6a/0xb0 drivers/tty/tty_ldisc.c:324
 #3: ffff8880b9c4d0c8 (lock#2){-.-.}-{2:2}, at: local_lock_acquire+0x7/0x130 include/linux/local_lock_internal.h:41

stack backtrace:
CPU: 0 PID: 10500 Comm: syz-executor.4 Not tainted 5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:105
 print_circular_bug+0xb17/0xdc0 kernel/locking/lockdep.c:2009
 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2131
 check_prev_add kernel/locking/lockdep.c:3051 [inline]
 check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174
 validate_chain kernel/locking/lockdep.c:3789 [inline]
 __lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015
 lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625
 __fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4552
 fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4566
 prepare_alloc_pages+0x151/0x5a0 mm/page_alloc.c:5164
 __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5363
 stack_depot_save+0x361/0x490 lib/stackdepot.c:303
 save_stack+0xf9/0x1f0 mm/page_owner.c:120
 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181
 prep_new_page mm/page_alloc.c:2433 [inline]
 __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5301
 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline]
 vm_area_alloc_pages mm/vmalloc.c:2793 [inline]
 __vmalloc_area_node mm/vmalloc.c:2863 [inline]
 __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2966
 __vmalloc_node mm/vmalloc.c:3015 [inline]
 vzalloc+0x75/0x80 mm/vmalloc.c:3085
 n_tty_open+0x19/0x150 drivers/tty/n_tty.c:1848
 tty_ldisc_open drivers/tty/tty_ldisc.c:449 [inline]
 tty_ldisc_setup+0x1ba/0x3c0 drivers/tty/tty_ldisc.c:776
 tty_init_dev+0x271/0x4c0 drivers/tty/tty_io.c:1453
 ptmx_open+0xdb/0x2c0 drivers/tty/pty.c:834
 chrdev_open+0x53b/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x7cb/0x1020 fs/open.c:826
 do_open fs/namei.c:3374 [inline]
 path_openat+0x27e7/0x36b0 fs/namei.c:3507
 do_filp_open+0x253/0x4d0 fs/namei.c:3534
 do_sys_openat2+0x124/0x460 fs/open.c:1204
 do_sys_open fs/open.c:1220 [inline]
 __do_sys_openat fs/open.c:1236 [inline]
 __se_sys_openat fs/open.c:1231 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1231
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
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:00007f24332b9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665d9
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 00007fffde713d0f R14: 00007f24332b9300 R15: 0000000000022000
BUG: sleeping function called from invalid context at mm/page_alloc.c:5167
in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 10500, name: syz-executor.4
INFO: lockdep is turned off.
irq event stamp: 2522
hardirqs last  enabled at (2521): [<ffffffff89db217b>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
hardirqs last  enabled at (2521): [<ffffffff89db217b>] _raw_spin_unlock_irqrestore+0x8b/0x120 kernel/locking/spinlock.c:191
hardirqs last disabled at (2522): [<ffffffff81be9e01>] __alloc_pages_bulk+0x801/0x1090 mm/page_alloc.c:5279
softirqs last  enabled at (0): [<ffffffff814b18eb>] copy_process+0x147b/0x5b00 kernel/fork.c:2065
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 0 PID: 10500 Comm: syz-executor.4 Not tainted 5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:105
 ___might_sleep+0x4e5/0x6b0 kernel/sched/core.c:9154
 prepare_alloc_pages+0x1c0/0x5a0 mm/page_alloc.c:5167
 __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5363
 stack_depot_save+0x361/0x490 lib/stackdepot.c:303
 save_stack+0xf9/0x1f0 mm/page_owner.c:120
 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181
 prep_new_page mm/page_alloc.c:2433 [inline]
 __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5301
 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline]
 vm_area_alloc_pages mm/vmalloc.c:2793 [inline]
 __vmalloc_area_node mm/vmalloc.c:2863 [inline]
 __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2966
 __vmalloc_node mm/vmalloc.c:3015 [inline]
 vzalloc+0x75/0x80 mm/vmalloc.c:3085
 n_tty_open+0x19/0x150 drivers/tty/n_tty.c:1848
 tty_ldisc_open drivers/tty/tty_ldisc.c:449 [inline]
 tty_ldisc_setup+0x1ba/0x3c0 drivers/tty/tty_ldisc.c:776
 tty_init_dev+0x271/0x4c0 drivers/tty/tty_io.c:1453
 ptmx_open+0xdb/0x2c0 drivers/tty/pty.c:834
 chrdev_open+0x53b/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x7cb/0x1020 fs/open.c:826
 do_open fs/namei.c:3374 [inline]
 path_openat+0x27e7/0x36b0 fs/namei.c:3507
 do_filp_open+0x253/0x4d0 fs/namei.c:3534
 do_sys_openat2+0x124/0x460 fs/open.c:1204
 do_sys_open fs/open.c:1220 [inline]
 __do_sys_openat fs/open.c:1236 [inline]
 __se_sys_openat fs/open.c:1231 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1231
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
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:00007f24332b9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665d9
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 00007fffde713d0f R14: 00007f24332b9300 R15: 0000000000022000