[ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ OK ] Started Getty on tty6. [ OK ] Started Getty on tty5. [ OK ] Started Getty on tty4. [ OK ] Started Getty on tty3. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started Getty on tty1. [ OK ] Started Getty on tty2. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Warning: Permanently added '10.128.0.64' (ECDSA) to the list of known hosts. Debian GNU/Linux 9 syzkaller ttyS0 executing program syzkaller login: [ 84.660189][ T37] audit: type=1400 audit(1622566898.375:8): avc: denied { execmem } for pid=8427 comm="syz-executor287" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1 [ 84.665292][ T8427] [ 84.683489][ T8427] ====================================================== [ 84.690506][ T8427] WARNING: possible circular locking dependency detected [ 84.697619][ T8427] 5.13.0-rc4-syzkaller #0 Not tainted [ 84.702996][ T8427] ------------------------------------------------------ [ 84.710195][ T8427] syz-executor287/8427 is trying to acquire lock: [ 84.716700][ T8427] ffff888145c392e0 (&bdev->bd_mutex){+.+.}-{3:3}, at: del_gendisk+0x24b/0xa00 [ 84.725709][ T8427] [ 84.725709][ T8427] but task is already holding lock: [ 84.733164][ T8427] ffffffff8ca6c348 (loop_ctl_mutex){+.+.}-{3:3}, at: loop_control_ioctl+0x7b/0x4f0 [ 84.742605][ T8427] [ 84.742605][ T8427] which lock already depends on the new lock. [ 84.742605][ T8427] [ 84.753198][ T8427] [ 84.753198][ T8427] the existing dependency chain (in reverse order) is: [ 84.763062][ T8427] [ 84.763062][ T8427] -> #1 (loop_ctl_mutex){+.+.}-{3:3}: [ 84.770732][ T8427] __mutex_lock+0x139/0x10c0 [ 84.775882][ T8427] lo_open+0x1a/0x130 [ 84.780593][ T8427] __blkdev_get+0x182/0xa30 [ 84.785646][ T8427] blkdev_get_by_dev+0x200/0x660 [ 84.791112][ T8427] blkdev_open+0x154/0x2b0 [ 84.796060][ T8427] do_dentry_open+0x4b9/0x11b0 [ 84.801752][ T8427] path_openat+0x1c0e/0x27e0 [ 84.807086][ T8427] do_filp_open+0x190/0x3d0 [ 84.812136][ T8427] do_sys_openat2+0x16d/0x420 [ 84.817459][ T8427] __x64_sys_open+0x119/0x1c0 [ 84.822700][ T8427] do_syscall_64+0x3a/0xb0 [ 84.828078][ T8427] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 84.834510][ T8427] [ 84.834510][ T8427] -> #0 (&bdev->bd_mutex){+.+.}-{3:3}: [ 84.842170][ T8427] __lock_acquire+0x2a17/0x5230 [ 84.847681][ T8427] lock_acquire+0x1ab/0x740 [ 84.852731][ T8427] __mutex_lock+0x139/0x10c0 [ 84.858177][ T8427] del_gendisk+0x24b/0xa00 [ 84.863450][ T8427] loop_control_ioctl+0x40d/0x4f0 [ 84.869208][ T8427] __x64_sys_ioctl+0x193/0x200 [ 84.874622][ T8427] do_syscall_64+0x3a/0xb0 [ 84.880299][ T8427] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 84.886835][ T8427] [ 84.886835][ T8427] other info that might help us debug this: [ 84.886835][ T8427] [ 84.897419][ T8427] Possible unsafe locking scenario: [ 84.897419][ T8427] [ 84.905336][ T8427] CPU0 CPU1 [ 84.910896][ T8427] ---- ---- [ 84.916452][ T8427] lock(loop_ctl_mutex); [ 84.920881][ T8427] lock(&bdev->bd_mutex); [ 84.927845][ T8427] lock(loop_ctl_mutex); [ 84.934794][ T8427] lock(&bdev->bd_mutex); [ 84.939248][ T8427] [ 84.939248][ T8427] *** DEADLOCK *** [ 84.939248][ T8427] [ 84.947682][ T8427] 1 lock held by syz-executor287/8427: [ 84.953232][ T8427] #0: ffffffff8ca6c348 (loop_ctl_mutex){+.+.}-{3:3}, at: loop_control_ioctl+0x7b/0x4f0 [ 84.963061][ T8427] [ 84.963061][ T8427] stack backtrace: [ 84.969058][ T8427] CPU: 1 PID: 8427 Comm: syz-executor287 Not tainted 5.13.0-rc4-syzkaller #0 [ 84.977918][ T8427] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 84.988282][ T8427] Call Trace: [ 84.991592][ T8427] dump_stack+0x141/0x1d7 [ 84.995950][ T8427] check_noncircular+0x25f/0x2e0 [ 85.001010][ T8427] ? kasan_save_stack+0x32/0x40 [ 85.006022][ T8427] ? print_circular_bug+0x1e0/0x1e0 [ 85.011321][ T8427] ? __kasan_slab_free+0xcd/0x100 [ 85.016536][ T8427] ? kernfs_put.part.0+0x2c4/0x540 [ 85.021762][ T8427] ? kernfs_put+0x42/0x50 [ 85.026189][ T8427] ? __kernfs_remove+0x703/0xa90 [ 85.031311][ T8427] ? kernfs_remove_by_name_ns+0x51/0xb0 [ 85.036878][ T8427] ? sysfs_remove_files+0x87/0xf0 [ 85.042226][ T8427] ? lockdep_lock+0xc6/0x200 [ 85.046947][ T8427] ? call_rcu_zapped+0xb0/0xb0 [ 85.051725][ T8427] ? find_held_lock+0x2d/0x110 [ 85.056502][ T8427] __lock_acquire+0x2a17/0x5230 [ 85.061455][ T8427] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 85.067719][ T8427] lock_acquire+0x1ab/0x740 [ 85.072422][ T8427] ? del_gendisk+0x24b/0xa00 [ 85.077069][ T8427] ? lock_release+0x720/0x720 [ 85.081862][ T8427] ? find_held_lock+0x2d/0x110 [ 85.086727][ T8427] __mutex_lock+0x139/0x10c0 [ 85.091336][ T8427] ? del_gendisk+0x24b/0xa00 [ 85.095946][ T8427] ? mutex_lock_io_nested+0xf20/0xf20 [ 85.101345][ T8427] ? del_gendisk+0x24b/0xa00 [ 85.106307][ T8427] ? __mutex_unlock_slowpath+0xe2/0x610 [ 85.111997][ T8427] ? mutex_lock_io_nested+0xf20/0xf20 [ 85.117496][ T8427] ? wait_for_completion_io+0x270/0x270 [ 85.123169][ T8427] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 85.129714][ T8427] ? kernfs_remove_by_name_ns+0x62/0xb0 [ 85.135294][ T8427] ? sysfs_remove_files+0x87/0xf0 [ 85.140428][ T8427] del_gendisk+0x24b/0xa00 [ 85.145140][ T8427] loop_control_ioctl+0x40d/0x4f0 [ 85.150193][ T8427] ? loop_lookup+0x1d0/0x1d0 [ 85.154884][ T8427] ? security_file_ioctl+0x5c/0xb0 [ 85.160068][ T8427] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70 [ 85.166356][ T8427] ? loop_lookup+0x1d0/0x1d0 [ 85.170957][ T8427] __x64_sys_ioctl+0x193/0x200 [ 85.175736][ T8427] do_syscall_64+0x3a/0xb0 [ 85.180268][ T8427] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 85.186267][ T8427] RIP: 0033:0x43ee49 [ 85.190343][ T8427] Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 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 c0 ff ff ff f7 d8 64 89 01 48 [ 85.210322][ T8427] RSP: 002b:00007ffd987add48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 85.218756][ T8427] RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043ee49 [ 85.227237][ T8427] RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003 [ 85.235223][ T8427] RBP: 0000000000402e30 R08: 0000000000000000 R09: 0000000000400488 [ 85.243207][ T8427] R10: 0000000000000