random: sshd: uninitialized urandom read (32 bytes read) audit: type=1400 audit(1542144225.848:7): avc: denied { map } for pid=1779 comm="syz-executor316" path="/root/syz-executor316239602" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 audit: type=1400 audit(1542144225.868:8): avc: denied { map } for pid=1779 comm="syz-executor316" path="/dev/ashmem" dev="devtmpfs" ino=1082 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1 ====================================================== WARNING: possible circular locking dependency detected 4.14.80+ #5 Not tainted ------------------------------------------------------ syz-executor316/1779 is trying to acquire lock: (cpu_hotplug_lock.rw_sem){++++}, at: [] get_online_cpus include/linux/cpu.h:138 [inline] (cpu_hotplug_lock.rw_sem){++++}, at: [] lru_add_drain_all+0xa/0x20 mm/swap.c:729 but task is already holding lock: (&sb->s_type->i_mutex_key#10){+.+.}, at: [] inode_lock include/linux/fs.h:713 [inline] (&sb->s_type->i_mutex_key#10){+.+.}, at: [] shmem_add_seals+0x132/0x1230 mm/shmem.c:2779 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&sb->s_type->i_mutex_key#10){+.+.}: down_write+0x34/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:713 [inline] shmem_fallocate+0x149/0xb20 mm/shmem.c:2852 ashmem_shrink_scan+0x1b6/0x4e0 drivers/staging/android/ashmem.c:453 ashmem_ioctl+0x2cc/0xe20 drivers/staging/android/ashmem.c:795 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #4 (ashmem_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xf5/0x1480 kernel/locking/mutex.c:893 ashmem_mmap+0x4c/0x430 drivers/staging/android/ashmem.c:369 call_mmap include/linux/fs.h:1787 [inline] mmap_region+0x836/0xfb0 mm/mmap.c:1731 do_mmap+0x551/0xb80 mm/mmap.c:1509 do_mmap_pgoff include/linux/mm.h:2167 [inline] vm_mmap_pgoff+0x180/0x1d0 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1559 [inline] SyS_mmap_pgoff+0xf8/0x1a0 mm/mmap.c:1517 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #3 (&mm->mmap_sem){++++}: __might_fault+0x137/0x1b0 mm/memory.c:4529 _copy_from_user+0x27/0x100 lib/usercopy.c:10 copy_from_user include/linux/uaccess.h:147 [inline] memdup_user+0x50/0x90 mm/util.c:168 strndup_user+0x5b/0xf0 mm/util.c:195 perf_event_set_filter kernel/events/core.c:8681 [inline] _perf_ioctl kernel/events/core.c:4838 [inline] perf_ioctl+0x961/0x1bb0 kernel/events/core.c:4875 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #2 (&cpuctx_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xf5/0x1480 kernel/locking/mutex.c:893 perf_event_init_cpu+0xab/0x150 kernel/events/core.c:11213 perf_event_init+0x295/0x2d4 kernel/events/core.c:11260 start_kernel+0x441/0x739 init/main.c:621 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #1 (pmus_lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xf5/0x1480 kernel/locking/mutex.c:893 perf_event_init_cpu+0x2c/0x150 kernel/events/core.c:11207 cpuhp_invoke_callback+0x1b5/0x1960 kernel/cpu.c:183 cpuhp_up_callbacks kernel/cpu.c:567 [inline] _cpu_up+0x22c/0x520 kernel/cpu.c:1126 do_cpu_up+0x13f/0x180 kernel/cpu.c:1160 smp_init+0x137/0x14b kernel/smp.c:578 kernel_init_freeable+0x186/0x39f init/main.c:1068 kernel_init+0xc/0x157 init/main.c:1000 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 -> #0 (cpu_hotplug_lock.rw_sem){++++}: lock_acquire+0x10f/0x380 kernel/locking/lockdep.c:3991 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] cpus_read_lock+0x39/0xb0 kernel/cpu.c:294 get_online_cpus include/linux/cpu.h:138 [inline] lru_add_drain_all+0xa/0x20 mm/swap.c:729 shmem_wait_for_pins mm/shmem.c:2683 [inline] shmem_add_seals+0x4db/0x1230 mm/shmem.c:2791 shmem_fcntl+0xea/0x120 mm/shmem.c:2826 do_fcntl+0x966/0xea0 fs/fcntl.c:421 SYSC_fcntl fs/fcntl.c:463 [inline] SyS_fcntl+0xc7/0x100 fs/fcntl.c:448 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Chain exists of: cpu_hotplug_lock.rw_sem --> ashmem_mutex --> &sb->s_type->i_mutex_key#10 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#10); lock(ashmem_mutex); lock(&sb->s_type->i_mutex_key#10); lock(cpu_hotplug_lock.rw_sem); *** DEADLOCK *** 1 lock held by syz-executor316/1779: #0: (&sb->s_type->i_mutex_key#10){+.+.}, at: [] inode_lock include/linux/fs.h:713 [inline] #0: (&sb->s_type->i_mutex_key#10){+.+.}, at: [] shmem_add_seals+0x132/0x1230 mm/shmem.c:2779 stack backtrace: CPU: 1 PID: 1779 Comm: syz-executor316 Not tainted 4.14.80+ #5 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 print_circular_bug.isra.18.cold.43+0x2d3/0x40c kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2ff9/0x4320 kernel/locking/lockdep.c:3487 lock_acquire+0x10f/0x380 kernel/locking/lockdep.c:3991 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] cpus_read_lock+0x39/0xb0 kernel/cpu.c:294 get_online_cpus include/linux/cpu.h:138 [inline] lru_add_drain_all+0xa/0x20 mm/swap.c:729 shmem_wait_for_pins mm/shmem.c:2683 [inline] shmem_add_seals+0x4db/0x1230 mm/shmem.c:2791 shmem_fcntl+0xea/0x120 mm/shmem.c:2826 do_fcntl+0x966/0xea0 fs/fcntl.c:421 SYSC_fcntl fs/fcntl.c:463 [inline] SyS_fcntl+0xc7/0x100 fs/fcntl.c:448 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x43ff79 RSP: 002b:00007ffd95b61058 EFLAGS: 00000207 ORIG_RAX: 0000000000000048 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ff79 RDX: 0000000000000008 RSI: 0000000000000409 RDI: 0000000000000007 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10