====================================================== WARNING: possible circular locking dependency detected 4.16.0-rc2+ #328 Not tainted ------------------------------------------------------ syz-executor3/3599 is trying to acquire lock: (&mm->mmap_sem){++++}, at: [<00000000a5ec897c>] __might_fault+0xe0/0x1d0 mm/memory.c:4570 but task is already holding lock: (ashmem_mutex){+.+.}, at: [<000000005e7b52f1>] ashmem_pin_unpin drivers/staging/android/ashmem.c:705 [inline] (ashmem_mutex){+.+.}, at: [<000000005e7b52f1>] ashmem_ioctl+0x3db/0x11b0 drivers/staging/android/ashmem.c:782 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (ashmem_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 ashmem_mmap+0x53/0x410 drivers/staging/android/ashmem.c:362 call_mmap include/linux/fs.h:1786 [inline] mmap_region+0xa99/0x15a0 mm/mmap.c:1705 do_mmap+0x6c0/0xe00 mm/mmap.c:1483 do_mmap_pgoff include/linux/mm.h:2223 [inline] vm_mmap_pgoff+0x1de/0x280 mm/util.c:355 SYSC_mmap_pgoff mm/mmap.c:1533 [inline] SyS_mmap_pgoff+0x462/0x5f0 mm/mmap.c:1491 SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 (&mm->mmap_sem){++++}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __might_fault+0x13a/0x1d0 mm/memory.c:4571 _copy_from_user+0x2c/0x110 lib/usercopy.c:10 copy_from_user include/linux/uaccess.h:147 [inline] ashmem_pin_unpin drivers/staging/android/ashmem.c:710 [inline] ashmem_ioctl+0x438/0x11b0 drivers/staging/android/ashmem.c:782 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(ashmem_mutex); lock(&mm->mmap_sem); lock(ashmem_mutex); lock(&mm->mmap_sem); *** DEADLOCK *** 1 lock held by syz-executor3/3599: #0: (ashmem_mutex){+.+.}, at: [<000000005e7b52f1>] ashmem_pin_unpin drivers/staging/android/ashmem.c:705 [inline] #0: (ashmem_mutex){+.+.}, at: [<000000005e7b52f1>] ashmem_ioctl+0x3db/0x11b0 drivers/staging/android/ashmem.c:782 stack backtrace: CPU: 0 PID: 3599 Comm: syz-executor3 Not tainted 4.16.0-rc2+ #328 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_circular_bug.isra.38+0x2cd/0x2dc kernel/locking/lockdep.c:1223 check_prev_add kernel/locking/lockdep.c:1863 [inline] check_prevs_add kernel/locking/lockdep.c:1976 [inline] validate_chain kernel/locking/lockdep.c:2417 [inline] __lock_acquire+0x30a8/0x3e00 kernel/locking/lockdep.c:3431 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __might_fault+0x13a/0x1d0 mm/memory.c:4571 _copy_from_user+0x2c/0x110 lib/usercopy.c:10 copy_from_user include/linux/uaccess.h:147 [inline] ashmem_pin_unpin drivers/staging/android/ashmem.c:710 [inline] ashmem_ioctl+0x438/0x11b0 drivers/staging/android/ashmem.c:782 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x453de9 RSP: 002b:00007f2540d64c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f2540d656d4 RCX: 0000000000453de9 RDX: 0000000000000000 RSI: 0000000000007709 RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000017a R14: 00000000006f2410 R15: 0000000000000000 kauditd_printk_skb: 829 callbacks suppressed audit: type=1400 audit(1519566488.719:14985): avc: denied { net_admin } for pid=4257 comm="syz-executor5" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.720:14986): avc: denied { net_admin } for pid=4257 comm="syz-executor5" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.779:14987): avc: denied { net_admin } for pid=4256 comm="syz-executor6" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.785:14988): avc: denied { net_admin } for pid=4258 comm="syz-executor2" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.789:14989): avc: denied { net_admin } for pid=4255 comm="syz-executor7" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.789:14990): avc: denied { net_admin } for pid=4255 comm="syz-executor7" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.794:14991): avc: denied { net_admin } for pid=4258 comm="syz-executor2" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.795:14992): avc: denied { net_admin } for pid=4258 comm="syz-executor2" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.797:14993): avc: denied { net_admin } for pid=4258 comm="syz-executor2" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 audit: type=1400 audit(1519566488.801:14994): avc: denied { net_admin } for pid=4256 comm="syz-executor6" capability=12 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1