netlink: 11 bytes leftover after parsing attributes in process `syz-executor4'.

======================================================
[ INFO: possible circular locking dependency detected ]
4.4.120-gd63fdf6 #28 Not tainted
-------------------------------------------------------
syz-executor5/8571 is trying to acquire lock:
 (&mm->mmap_sem){++++++}, at: [<ffffffff81495684>] __might_fault+0xe4/0x1d0 mm/memory.c:3809

but task is already holding lock:
 (ashmem_mutex){+.+.+.}, at: [<ffffffff82c628a7>] ashmem_pin_unpin drivers/staging/android/ashmem.c:701 [inline]
 (ashmem_mutex){+.+.+.}, at: [<ffffffff82c628a7>] 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:

-> #1 (ashmem_mutex){+.+.+.}:
       [<ffffffff8123d7ce>] lock_acquire+0x15e/0x460 kernel/locking/lockdep.c:3592
       [<ffffffff8376a39b>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
       [<ffffffff8376a39b>] mutex_lock_nested+0xbb/0x850 kernel/locking/mutex.c:621
       [<ffffffff82c61463>] ashmem_mmap+0x53/0x400 drivers/staging/android/ashmem.c:366
       [<ffffffff814b0e4f>] mmap_region+0x94f/0x1250 mm/mmap.c:1664
       [<ffffffff814b1c4d>] do_mmap+0x4fd/0x9d0 mm/mmap.c:1441
       [<ffffffff814700ce>] do_mmap_pgoff include/linux/mm.h:1915 [inline]
       [<ffffffff814700ce>] vm_mmap_pgoff+0x16e/0x1c0 mm/util.c:296
       [<ffffffff814afe1f>] SYSC_mmap_pgoff mm/mmap.c:1491 [inline]
       [<ffffffff814afe1f>] SyS_mmap_pgoff+0x33f/0x560 mm/mmap.c:1449
       [<ffffffff8101beb6>] SYSC_mmap arch/x86/kernel/sys_x86_64.c:95 [inline]
       [<ffffffff8101beb6>] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:86
       [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98

-> #0 (&mm->mmap_sem){++++++}:
       [<ffffffff8123ab2f>] check_prev_add kernel/locking/lockdep.c:1853 [inline]
       [<ffffffff8123ab2f>] check_prevs_add kernel/locking/lockdep.c:1958 [inline]
       [<ffffffff8123ab2f>] validate_chain kernel/locking/lockdep.c:2144 [inline]
       [<ffffffff8123ab2f>] __lock_acquire+0x371f/0x4b50 kernel/locking/lockdep.c:3213
       [<ffffffff8123d7ce>] lock_acquire+0x15e/0x460 kernel/locking/lockdep.c:3592
       [<ffffffff814956ea>] __might_fault+0x14a/0x1d0 mm/memory.c:3810
       [<ffffffff82c628f4>] copy_from_user arch/x86/include/asm/uaccess.h:724 [inline]
       [<ffffffff82c628f4>] ashmem_pin_unpin drivers/staging/android/ashmem.c:706 [inline]
       [<ffffffff82c628f4>] ashmem_ioctl+0x3b4/0xfa0 drivers/staging/android/ashmem.c:778
       [<ffffffff81559daa>] vfs_ioctl fs/ioctl.c:43 [inline]
       [<ffffffff81559daa>] do_vfs_ioctl+0x7aa/0xee0 fs/ioctl.c:607
       [<ffffffff8155a56f>] SYSC_ioctl fs/ioctl.c:622 [inline]
       [<ffffffff8155a56f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613
       [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98

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-executor5/8571:
 #0:  (ashmem_mutex){+.+.+.}, at: [<ffffffff82c628a7>] ashmem_pin_unpin drivers/staging/android/ashmem.c:701 [inline]
 #0:  (ashmem_mutex){+.+.+.}, at: [<ffffffff82c628a7>] ashmem_ioctl+0x367/0xfa0 drivers/staging/android/ashmem.c:778

stack backtrace:
CPU: 1 PID: 8571 Comm: syz-executor5 Not tainted 4.4.120-gd63fdf6 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 0c4f5ae19d568c13 ffff8801c8b979b8 ffffffff81d0408d
 ffffffff851a0010 ffffffff851a0010 ffffffff851be2b0 ffff8800b35c68f8
 ffff8800b35c6000 ffff8801c8b97a00 ffffffff81233ba1 ffff8800b35c68f8
Call Trace:
 [<ffffffff81d0408d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d0408d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81233ba1>] print_circular_bug+0x271/0x310 kernel/locking/lockdep.c:1226
 [<ffffffff8123ab2f>] check_prev_add kernel/locking/lockdep.c:1853 [inline]
 [<ffffffff8123ab2f>] check_prevs_add kernel/locking/lockdep.c:1958 [inline]
 [<ffffffff8123ab2f>] validate_chain kernel/locking/lockdep.c:2144 [inline]
 [<ffffffff8123ab2f>] __lock_acquire+0x371f/0x4b50 kernel/locking/lockdep.c:3213
 [<ffffffff8123d7ce>] lock_acquire+0x15e/0x460 kernel/locking/lockdep.c:3592
 [<ffffffff814956ea>] __might_fault+0x14a/0x1d0 mm/memory.c:3810
 [<ffffffff82c628f4>] copy_from_user arch/x86/include/asm/uaccess.h:724 [inline]
 [<ffffffff82c628f4>] ashmem_pin_unpin drivers/staging/android/ashmem.c:706 [inline]
 [<ffffffff82c628f4>] ashmem_ioctl+0x3b4/0xfa0 drivers/staging/android/ashmem.c:778
 [<ffffffff81559daa>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff81559daa>] do_vfs_ioctl+0x7aa/0xee0 fs/ioctl.c:607
 [<ffffffff8155a56f>] SYSC_ioctl fs/ioctl.c:622 [inline]
 [<ffffffff8155a56f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:613
 [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98
audit: type=1400 audit(1520444810.165:38): avc:  denied  { ioctl } for  pid=8566 comm="syz-executor4" path="socket:[19270]" dev="sockfs" ino=19270 ioctlcmd=8933 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(1520444810.165:39): avc:  denied  { create } for  pid=8583 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_connector_socket permissive=1
audit: type=1400 audit(1520444810.185:41): avc:  denied  { setopt } for  pid=8566 comm="syz-executor4" 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(1520444810.175:40): avc:  denied  { write } for  pid=8583 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_connector_socket permissive=1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=28005 sclass=netlink_route_socket
audit: type=1400 audit(1520444810.755:42): avc:  denied  { create } for  pid=8655 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_scsitransport_socket permissive=1
audit: type=1400 audit(1520444810.815:43): avc:  denied  { create } for  pid=8667 comm="syz-executor1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_rdma_socket permissive=1
BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor5/10234
caller is __this_cpu_preempt_check+0x1c/0x20 lib/smp_processor_id.c:62
CPU: 0 PID: 10234 Comm: syz-executor5 Not tainted 4.4.120-gd63fdf6 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 1f3e745923b55e94 ffff8801c3b07638 ffffffff81d0408d
 0000000000000000 ffffffff839fe5a0 ffffffff83cefc20 ffff8801d7959800
 0000000000000003 ffff8801c3b07678 ffffffff81d63fe4 ffff8800b204ee88
Call Trace:
 [<ffffffff81d0408d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d0408d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81d63fe4>] check_preemption_disabled+0x1d4/0x200 lib/smp_processor_id.c:46
 [<ffffffff81d6404c>] __this_cpu_preempt_check+0x1c/0x20 lib/smp_processor_id.c:62
 [<ffffffff8312b439>] tcp_try_coalesce+0x249/0x4d0 net/ipv4/tcp_input.c:4278
 [<ffffffff831335b7>] tcp_queue_rcv+0x127/0x720 net/ipv4/tcp_input.c:4485
 [<ffffffff8314ae8b>] tcp_send_rcvq+0x39b/0x450 net/ipv4/tcp_input.c:4531
 [<ffffffff831220ef>] tcp_sendmsg+0x1e8f/0x2b10 net/ipv4/tcp.c:1134
 [<ffffffff831d7d4c>] inet_sendmsg+0x2bc/0x4c0 net/ipv4/af_inet.c:755
 [<ffffffff82deba6a>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82deba6a>] sock_sendmsg+0xca/0x110 net/socket.c:635
 [<ffffffff82debcd6>] sock_write_iter+0x226/0x3b0 net/socket.c:834
 [<ffffffff8151e0b8>] do_iter_readv_writev+0x138/0x1e0 fs/read_write.c:664
 [<ffffffff8151f852>] do_readv_writev+0x2d2/0x6e0 fs/read_write.c:808
 [<ffffffff8151fd8b>] vfs_writev+0x7b/0xb0 fs/read_write.c:847
 [<ffffffff81522249>] SYSC_writev fs/read_write.c:880 [inline]
 [<ffffffff81522249>] SyS_writev+0xd9/0x240 fs/read_write.c:872
 [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98
BUG: using __this_cpu_add() in preemptible [00000000] code: syz-executor5/10286
caller is __this_cpu_preempt_check+0x1c/0x20 lib/smp_processor_id.c:62
CPU: 0 PID: 10286 Comm: syz-executor5 Not tainted 4.4.120-gd63fdf6 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 2cc4cca80424a034 ffff8800ba037638 ffffffff81d0408d
 0000000000000000 ffffffff839fe5a0 ffffffff83cefc20 ffff8800ba204800
 0000000000000003 ffff8800ba037678 ffffffff81d63fe4 ffff8801c687e988
Call Trace:
 [<ffffffff81d0408d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d0408d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff81d63fe4>] check_preemption_disabled+0x1d4/0x200 lib/smp_processor_id.c:46
 [<ffffffff81d6404c>] __this_cpu_preempt_check+0x1c/0x20 lib/smp_processor_id.c:62
 [<ffffffff8312b439>] tcp_try_coalesce+0x249/0x4d0 net/ipv4/tcp_input.c:4278
 [<ffffffff831335b7>] tcp_queue_rcv+0x127/0x720 net/ipv4/tcp_input.c:4485
 [<ffffffff8314ae8b>] tcp_send_rcvq+0x39b/0x450 net/ipv4/tcp_input.c:4531
 [<ffffffff831220ef>] tcp_sendmsg+0x1e8f/0x2b10 net/ipv4/tcp.c:1134
 [<ffffffff831d7d4c>] inet_sendmsg+0x2bc/0x4c0 net/ipv4/af_inet.c:755
 [<ffffffff82deba6a>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82deba6a>] sock_sendmsg+0xca/0x110 net/socket.c:635
 [<ffffffff82debcd6>] sock_write_iter+0x226/0x3b0 net/socket.c:834
 [<ffffffff8151e0b8>] do_iter_readv_writev+0x138/0x1e0 fs/read_write.c:664
 [<ffffffff8151f852>] do_readv_writev+0x2d2/0x6e0 fs/read_write.c:808
 [<ffffffff8151fd8b>] vfs_writev+0x7b/0xb0 fs/read_write.c:847
 [<ffffffff81522249>] SYSC_writev fs/read_write.c:880 [inline]
 [<ffffffff81522249>] SyS_writev+0xd9/0x240 fs/read_write.c:872
 [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98
audit: type=1401 audit(1520444819.655:44): op=setxattr invalid_context="/dev/rfkill"
audit: type=1401 audit(1520444819.705:45): op=setxattr invalid_context="/dev/rfkill"