====================================================== [ INFO: possible circular locking dependency detected ] 4.4.119-g024f962 #27 Not tainted ------------------------------------------------------- syz-executor5/15290 is trying to acquire lock: audit: type=1400 audit(1519856125.383:158): avc: denied { set_context_mgr } for pid=15297 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=binder permissive=1 binder: 15297:15300 ioctl c0306201 20007000 returned -14 binder_alloc: binder_alloc_mmap_handler: 15297 20000000-20002000 already mapped failed -16 binder: BINDER_SET_CONTEXT_MGR already set binder: 15297:15300 ioctl 40046207 0 returned -16 binder: 15297:15301 ioctl c0306201 20007000 returned -14 (&mm->mmap_sem){++++++}, at: [] __might_fault+0xe4/0x1d0 mm/memory.c:3809 but task is already holding lock: ([ 134.232382] binder: BINDER_SET_CONTEXT_MGR already set binder: 15304:15305 ioctl 40046207 0 returned -16 binder: 15304:15305 ioctl c0306201 20007000 returned -14 ashmem_mutex){+.+.+.}, at: [] ashmem_pin_unpin drivers/staging/android/ashmem.c:701 [inline] ashmem_mutex){+.+.+.}, at: [] ashmem_ioctl+0x367/0xfa0 drivers/staging/android/ashmem.c:778 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: [] lock_acquire+0x15e/0x460 kernel/locking/lockdep.c:3592 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_nested+0xbb/0x850 kernel/locking/mutex.c:621 [] ashmem_mmap+0x53/0x400 drivers/staging/android/ashmem.c:366 [] mmap_region+0x94f/0x1250 mm/mmap.c:1664 [] do_mmap+0x4fd/0x9d0 mm/mmap.c:1441 [] do_mmap_pgoff include/linux/mm.h:1915 [inline] [] vm_mmap_pgoff+0x16e/0x1c0 mm/util.c:296 [] SYSC_mmap_pgoff mm/mmap.c:1491 [inline] [] SyS_mmap_pgoff+0x33f/0x560 mm/mmap.c:1449 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x321/0x8a0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 [] check_prev_add kernel/locking/lockdep.c:1853 [inline] [] check_prevs_add kernel/locking/lockdep.c:1958 [inline] [] validate_chain kernel/locking/lockdep.c:2144 [inline] [] __lock_acquire+0x371f/0x4b50 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x460 kernel/locking/lockdep.c:3592 [] __might_fault+0x14a/0x1d0 mm/memory.c:3810 [] copy_from_user arch/x86/include/asm/uaccess.h:724 [inline] [] ashmem_pin_unpin drivers/staging/android/ashmem.c:706 [inline] [] ashmem_ioctl+0x3b4/0xfa0 drivers/staging/android/ashmem.c:778 [] compat_ashmem_ioctl+0x3e/0x50 drivers/staging/android/ashmem.c:809 [] C_SYSC_ioctl fs/compat_ioctl.c:1592 [inline] [] compat_SyS_ioctl+0x28a/0x2540 fs/compat_ioctl.c:1544 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x321/0x8a0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 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-executor5/15290: #0: (ashmem_mutex){+.+.+.}, at: [] ashmem_pin_unpin drivers/staging/android/ashmem.c:701 [inline] #0: (ashmem_mutex){+.+.+.}, at: [] ashmem_ioctl+0x367/0xfa0 drivers/staging/android/ashmem.c:778 stack backtrace: CPU: 0 PID: 15290 Comm: syz-executor5 Not tainted 4.4.119-g024f962 #27 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 ea6871e2177bdb09 ffff8801c473f8a8 ffffffff81d0402d ffffffff851a0010 ffffffff851a0010 ffffffff851be970 ffff8800b8c250f8 ffff8800b8c24800 ffff8801c473f8f0 ffffffff81233ba1 ffff8800b8c250f8 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x124 lib/dump_stack.c:51 [] print_circular_bug+0x271/0x310 kernel/locking/lockdep.c:1226 [] check_prev_add kernel/locking/lockdep.c:1853 [inline] [] check_prevs_add kernel/locking/lockdep.c:1958 [inline] [] validate_chain kernel/locking/lockdep.c:2144 [inline] [] __lock_acquire+0x371f/0x4b50 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x460 kernel/locking/lockdep.c:3592 [] __might_fault+0x14a/0x1d0 mm/memory.c:3810 [] copy_from_user arch/x86/include/asm/uaccess.h:724 [inline] [] ashmem_pin_unpin drivers/staging/android/ashmem.c:706 [inline] [] ashmem_ioctl+0x3b4/0xfa0 drivers/staging/android/ashmem.c:778 [] compat_ashmem_ioctl+0x3e/0x50 drivers/staging/android/ashmem.c:809 [] C_SYSC_ioctl fs/compat_ioctl.c:1592 [inline] [] compat_SyS_ioctl+0x28a/0x2540 fs/compat_ioctl.c:1544 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x321/0x8a0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 audit: type=1326 audit(1519856126.513:159): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 pid=15379 comm="syz-executor4" exe="/root/syz-executor4" sig=9 arch=40000003 syscall=240 compat=1 ip=0xf77b1ba9 code=0x0 audit: type=1400 audit(1519856126.513:160): avc: denied { create } for pid=15381 comm="syz-executor6" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit_printk_skb: 9 callbacks suppressed audit: type=1400 audit(1519856127.563:164): avc: denied { create } for pid=15495 comm="syz-executor2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_fib_lookup_socket permissive=1 audit: type=1400 audit(1519856127.653:165): avc: denied { create } for pid=15495 comm="syz-executor2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_fib_lookup_socket permissive=1 qtaguid: iface_stat: iface_check_stats_reset_and_adjust(lo): iface reset its stats unexpectedly audit: type=1400 audit(1519856133.263:166): avc: denied { create } for pid=16154 comm="syz-executor3" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit: type=1400 audit(1519856133.343:167): avc: denied { create } for pid=16154 comm="syz-executor3" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit: type=1400 audit(1519856133.993:168): avc: denied { create } for pid=16237 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit: type=1400 audit(1519856134.033:169): avc: denied { ioctl } for pid=16237 comm="syz-executor0" path="socket:[33608]" dev="sockfs" ino=33608 ioctlcmd=6420 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit: type=1400 audit(1519856134.073:170): avc: denied { create } for pid=16237 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit: type=1400 audit(1519856134.103:171): avc: denied { ioctl } for pid=16237 comm="syz-executor0" path="socket:[34039]" dev="sockfs" ino=34039 ioctlcmd=6420 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit: type=1400 audit(1519856135.313:172): avc: denied { create } for pid=16397 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 audit: type=1400 audit(1519856135.363:173): avc: denied { create } for pid=16397 comm="syz-executor0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1