=============================
WARNING: suspicious RCU usage
4.14.154+ #0 Not tainted
-----------------------------
include/linux/radix-tree.h:238 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by syz-executor.1/15617:
 #0:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<0000000019f0b7d2>] inode_lock include/linux/fs.h:724 [inline]
 #0:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<0000000019f0b7d2>] shmem_add_seals+0x12b/0xf80 mm/shmem.c:2831
 #1:  (&(&mapping->tree_lock)->rlock){-.-.}, at: [<00000000daec3549>] spin_lock_irq include/linux/spinlock.h:342 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-.-.}, at: [<00000000daec3549>] shmem_tag_pins mm/shmem.c:2685 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-.-.}, at: [<00000000daec3549>] shmem_wait_for_pins mm/shmem.c:2726 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-.-.}, at: [<00000000daec3549>] shmem_add_seals+0x2e1/0xf80 mm/shmem.c:2843

stack backtrace:
CPU: 0 PID: 15617 Comm: syz-executor.1 Not tainted 4.14.154+ #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xe5/0x154 lib/dump_stack.c:58
 radix_tree_deref_slot include/linux/radix-tree.h:238 [inline]
 shmem_tag_pins mm/shmem.c:2687 [inline]
 shmem_wait_for_pins mm/shmem.c:2726 [inline]
 shmem_add_seals+0x9d2/0xf80 mm/shmem.c:2843
 shmem_fcntl+0xea/0x120 mm/shmem.c:2878
 do_fcntl+0x5c8/0xd20 fs/fcntl.c:421
 SYSC_fcntl fs/fcntl.c:463 [inline]
 SyS_fcntl+0xc6/0x100 fs/fcntl.c:448
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a639
RSP: 002b:00007fc322fd2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000048
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a639
RDX: 000000000000000d RSI: 0000000000000409 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc322fd36d4
R13: 00000000004c1068 R14: 00000000004d3c60 R15: 00000000ffffffff
audit: type=1400 audit(2000000036.850:52): avc:  denied  { map } for  pid=15677 comm="syz-executor.0" path="socket:[26423]" dev="sockfs" ino=26423 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=packet_socket permissive=1
input: syz1 as /devices/virtual/input/input7
input: syz1 as /devices/virtual/input/input8
netlink: 32 bytes leftover after parsing attributes in process `syz-executor.5'.
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=33029 sclass=netlink_route_socket pig=16281 comm=syz-executor.0
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=33029 sclass=netlink_route_socket pig=16281 comm=syz-executor.0
audit: type=1400 audit(2000000045.380:53): avc:  denied  { write } for  pid=16355 comm="syz-executor.1" path="socket:[27951]" dev="sockfs" ino=27951 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
netlink: 3 bytes leftover after parsing attributes in process `syz-executor.1'.