WARNING: suspicious RCU usage
4.14.0+ #129 Not tainted
netlink: 1 bytes leftover after parsing attributes in process `syz-executor1'.
netlink: 1 bytes leftover after parsing attributes in process `syz-executor1'.
-----------------------------
./include/trace/events/kmem.h:142 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz-executor3/14792:
 #0:  (sk_lock-AF_ALG){+.+.}, at: [<ffffffff8239ac22>] lock_sock include/net/sock.h:1465 [inline]
 #0:  (sk_lock-AF_ALG){+.+.}, at: [<ffffffff8239ac22>] af_alg_wait_for_data+0x2f2/0x650 crypto/af_alg.c:768

stack backtrace:
CPU: 0 PID: 14792 Comm: syz-executor3 Not tainted 4.14.0+ #129
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+0x194/0x257 lib/dump_stack.c:53
 lockdep_rcu_suspicious+0x123/0x170 kernel/locking/lockdep.c:4675
 trace_kfree include/trace/events/kmem.h:137 [inline]
 kfree+0x20a/0x250 mm/slab.c:3796
 blkcipher_walk_done+0x72b/0xde0 crypto/blkcipher.c:139
 encrypt+0x50a/0xaf0 crypto/salsa20_generic.c:208
 skcipher_crypt_blkcipher crypto/skcipher.c:619 [inline]
 skcipher_decrypt_blkcipher+0x213/0x310 crypto/skcipher.c:637
 crypto_skcipher_decrypt include/crypto/skcipher.h:463 [inline]
 _skcipher_recvmsg crypto/algif_skcipher.c:133 [inline]
 skcipher_recvmsg+0xb06/0xf30 crypto/algif_skcipher.c:164
 sock_recvmsg_nosec net/socket.c:805 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:812
 ___sys_recvmsg+0x29b/0x630 net/socket.c:2207
 __sys_recvmsg+0xe2/0x210 net/socket.c:2252
 SYSC_recvmsg net/socket.c:2264 [inline]
 SyS_recvmsg+0x2d/0x50 net/socket.c:2259
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452879
RSP: 002b:00007f521f742be8 EFLAGS: 00000212 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452879
RDX: 0000000000000100 RSI: 0000000020f77fc8 RDI: 0000000000000014
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f2608
R13: 00000000ffffffff R14: 00007f521f7436d4 R15: 0000000000000003
page:ffffea00071347c0 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x2fffc0000000000()
raw: 02fffc0000000000 0000000000000000 0000000000000000 00000000ffffffff
raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000
page dumped because: VM_BUG_ON_PAGE(page_ref_count(page) == 0)
------------[ cut here ]------------
kernel BUG at ./include/linux/mm.h:482!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 14792 Comm: syz-executor3 Not tainted 4.14.0+ #129
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d94a8080 task.stack: ffff8801c4d18000
RIP: 0010:put_page_testzero include/linux/mm.h:482 [inline]
RIP: 0010:__free_pages+0x118/0x150 mm/page_alloc.c:4288
RSP: 0018:ffff8801c4d1f700 EFLAGS: 00010203
RAX: 0000000000000000 RBX: ffffea00071347c0 RCX: 0000000000000000
RDX: 00000000001f0100 RSI: 1ffff100389a3e2c RDI: ffffed00389a3ed0
RBP: ffff8801c4d1f790 R08: 1ffff100389a3dee R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff100389a3ee1
R13: 1ffff100389a3ee5 R14: 0000000000000000 R15: ffff8801c4d1f768
FS:  00007f521f743700(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558bc182fa98 CR3: 00000001d7f6a000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 free_pages+0x51/0x90 mm/page_alloc.c:4302
 blkcipher_walk_done+0x767/0xde0 crypto/blkcipher.c:141
 encrypt+0x50a/0xaf0 crypto/salsa20_generic.c:208
 skcipher_crypt_blkcipher crypto/skcipher.c:619 [inline]
 skcipher_decrypt_blkcipher+0x213/0x310 crypto/skcipher.c:637
 crypto_skcipher_decrypt include/crypto/skcipher.h:463 [inline]
 _skcipher_recvmsg crypto/algif_skcipher.c:133 [inline]
 skcipher_recvmsg+0xb06/0xf30 crypto/algif_skcipher.c:164
 sock_recvmsg_nosec net/socket.c:805 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:812
 ___sys_recvmsg+0x29b/0x630 net/socket.c:2207
 __sys_recvmsg+0xe2/0x210 net/socket.c:2252
 SYSC_recvmsg net/socket.c:2264 [inline]
 SyS_recvmsg+0x2d/0x50 net/socket.c:2259
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452879
RSP: 002b:00007f521f742be8 EFLAGS: 00000212 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452879
RDX: 0000000000000100 RSI: 0000000020f77fc8 RDI: 0000000000000014
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f2608
R13: 00000000ffffffff R14: 00007f521f7436d4 R15: 0000000000000003
Code: 20 08 00 00 00 00 48 83 c4 68 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 29 f5 ff ff eb cf 48 c7 c6 80 2a 30 85 48 89 df e8 38 61 0c 00 <0f> 0b 4c 89 ef 89 b5 74 ff ff ff e8 78 f1 19 00 8b b5 74 ff ff 
RIP: put_page_testzero include/linux/mm.h:482 [inline] RSP: ffff8801c4d1f700
RIP: __free_pages+0x118/0x150 mm/page_alloc.c:4288 RSP: ffff8801c4d1f700
---[ end trace cc72021c066ad15f ]---