audit: type=1400 audit(1521688188.173:8): avc:  denied  { create } for  pid=5229 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_crypto_socket permissive=1

======================================================
[ INFO: possible circular locking dependency detected ]
4.4.120-gd63fdf6 #28 Not tainted
-------------------------------------------------------
syz-executor6/5238 is trying to acquire lock:
 (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<ffffffff81463361>] shmem_file_llseek+0xf1/0x240 mm/shmem.c:1816

but task is already holding lock:
 (ashmem_mutex){+.+.+.}, at: [<ffffffff82c62016>] ashmem_llseek+0x56/0x1f0 drivers/staging/android/ashmem.c:330

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (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

-> #1 (&mm->mmap_sem){++++++}:
       [<ffffffff8123d7ce>] lock_acquire+0x15e/0x460 kernel/locking/lockdep.c:3592
       [<ffffffff814956ea>] __might_fault+0x14a/0x1d0 mm/memory.c:3810
       [<ffffffff8155ab22>] copy_to_user arch/x86/include/asm/uaccess.h:760 [inline]
       [<ffffffff8155ab22>] filldir+0x162/0x2d0 fs/readdir.c:180
       [<ffffffff8159820e>] dir_emit_dot include/linux/fs.h:3070 [inline]
       [<ffffffff8159820e>] dir_emit_dots include/linux/fs.h:3081 [inline]
       [<ffffffff8159820e>] dcache_readdir+0x11e/0x7b0 fs/libfs.c:150
       [<ffffffff8155a768>] iterate_dir+0x1c8/0x420 fs/readdir.c:42
       [<ffffffff8155b45a>] SYSC_getdents fs/readdir.c:215 [inline]
       [<ffffffff8155b45a>] SyS_getdents+0x14a/0x270 fs/readdir.c:196
       [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98

-> #0 (&sb->s_type->i_mutex_key#10){+.+.+.}:
       [<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
       [<ffffffff8376a39b>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
       [<ffffffff8376a39b>] mutex_lock_nested+0xbb/0x850 kernel/locking/mutex.c:621
       [<ffffffff81463361>] shmem_file_llseek+0xf1/0x240 mm/shmem.c:1816
       [<ffffffff8151c762>] vfs_llseek+0xa2/0xd0 fs/read_write.c:260
       [<ffffffff82c620a7>] ashmem_llseek+0xe7/0x1f0 drivers/staging/android/ashmem.c:342
       [<ffffffff8151e56b>] vfs_llseek fs/read_write.c:260 [inline]
       [<ffffffff8151e56b>] SYSC_lseek fs/read_write.c:285 [inline]
       [<ffffffff8151e56b>] SyS_lseek+0xeb/0x170 fs/read_write.c:276
       [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98

other info that might help us debug this:

Chain exists of:
  &sb->s_type->i_mutex_key#10 --> &mm->mmap_sem --> ashmem_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(ashmem_mutex);
                               lock(&mm->mmap_sem);
                               lock(ashmem_mutex);
  lock(&sb->s_type->i_mutex_key#10);

 *** DEADLOCK ***

1 lock held by syz-executor6/5238:
 #0:  (ashmem_mutex){+.+.+.}, at: [<ffffffff82c62016>] ashmem_llseek+0x56/0x1f0 drivers/staging/android/ashmem.c:330

stack backtrace:
CPU: 0 PID: 5238 Comm: syz-executor6 Not tainted 4.4.120-gd63fdf6 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 4e0847cdc01d079b ffff8801c59afad8 ffffffff81d0408d
 ffffffff851a0010 ffffffff851a9d00 ffffffff851be610 ffff8801d1ed38f8
 ffff8801d1ed3000 ffff8801c59afb20 ffffffff81233ba1 ffff8801d1ed38f8
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
 [<ffffffff8376a39b>] __mutex_lock_common kernel/locking/mutex.c:521 [inline]
 [<ffffffff8376a39b>] mutex_lock_nested+0xbb/0x850 kernel/locking/mutex.c:621
 [<ffffffff81463361>] shmem_file_llseek+0xf1/0x240 mm/shmem.c:1816
 [<ffffffff8151c762>] vfs_llseek+0xa2/0xd0 fs/read_write.c:260
 [<ffffffff82c620a7>] ashmem_llseek+0xe7/0x1f0 drivers/staging/android/ashmem.c:342
 [<ffffffff8151e56b>] vfs_llseek fs/read_write.c:260 [inline]
 [<ffffffff8151e56b>] SYSC_lseek fs/read_write.c:285 [inline]
 [<ffffffff8151e56b>] SyS_lseek+0xeb/0x170 fs/read_write.c:276
 [<ffffffff8377395f>] entry_SYSCALL_64_fastpath+0x1c/0x98
audit: type=1400 audit(1521688188.203:9): avc:  denied  { create } for  pid=5244 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(1521688188.213:10): avc:  denied  { write } for  pid=5244 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
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=2560 sclass=netlink_route_socket
audit: type=1400 audit(1521688188.323:11): avc:  denied  { set_context_mgr } for  pid=5232 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
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=2560 sclass=netlink_route_socket
audit: type=1400 audit(1521688188.333:12): avc:  denied  { call } for  pid=5232 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_alloc: 5232: binder_alloc_buf, no vma
binder: 5232:5236 transaction failed 29189/-3, size 40-8 line 3128
binder: undelivered TRANSACTION_ERROR: 29189
audit: type=1400 audit(1521688189.253:13): avc:  denied  { setopt } for  pid=5415 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_generic_socket permissive=1
mmap: syz-executor1 (5425) uses deprecated remap_file_pages() syscall. See Documentation/vm/remap_file_pages.txt.
capability: warning: `syz-executor7' uses 32-bit capabilities (legacy support in use)
binder: 5536:5537 Release 1 refcount change on invalid ref 0 ret -22
binder: BINDER_SET_CONTEXT_MGR already set
binder: 5536:5537 ioctl 40046207 0 returned -16
binder: 5536:5555 Release 1 refcount change on invalid ref 0 ret -22
audit: type=1400 audit(1521688190.403:14): avc:  denied  { dyntransition } for  pid=5625 comm="syz-executor2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0 tclass=process permissive=1
netlink: 28 bytes leftover after parsing attributes in process `syz-executor2'.
netlink: 28 bytes leftover after parsing attributes in process `syz-executor2'.
audit: type=1400 audit(1521688192.083:15): avc:  denied  { setattr } for  pid=6268 comm="syz-executor5" name="smaps" dev="proc" ino=14308 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=file permissive=1
audit: type=1400 audit(1521688194.093:16): avc:  denied  { execute } for  pid=6833 comm="syz-executor5" path="/proc/355/task/356/smaps" dev="proc" ino=16086 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=file permissive=1
audit: type=1400 audit(1521688195.343:17): avc:  denied  { setattr } for  pid=7342 comm="syz-executor6" name="task" dev="proc" ino=18499 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=dir permissive=1