netlink: 72 bytes leftover after parsing attributes in process `syz-executor2'.
WARNING: suspicious RCU usage
4.15.0-rc2+ #152 Not tainted
-----------------------------
./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-executor3/15773:
 #0:  (sk_lock-AF_ALG){+.+.}, at: [<000000008cd1e723>] lock_sock include/net/sock.h:1461 [inline]
 #0:  (sk_lock-AF_ALG){+.+.}, at: [<000000008cd1e723>] af_alg_wait_for_data+0x2f2/0x650 crypto/af_alg.c:768

stack backtrace:
CPU: 1 PID: 15773 Comm: syz-executor3 Not tainted 4.15.0-rc2+ #152
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:622 [inline]
 skcipher_encrypt_blkcipher+0x213/0x310 crypto/skcipher.c:631
 crypto_skcipher_encrypt include/crypto/skcipher.h:445 [inline]
 _skcipher_recvmsg crypto/algif_skcipher.c:144 [inline]
 skcipher_recvmsg+0x9e8/0xf20 crypto/algif_skcipher.c:165
 sock_recvmsg_nosec net/socket.c:809 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:816
 sock_read_iter+0x361/0x560 net/socket.c:893
 call_read_iter include/linux/fs.h:1766 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 __vfs_read+0x6ad/0xa00 fs/read_write.c:413
 vfs_read+0x124/0x360 fs/read_write.c:447
 SYSC_read fs/read_write.c:573 [inline]
 SyS_read+0xef/0x220 fs/read_write.c:566
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007f656c530c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452a39
RDX: 00000000000000be RSI: 0000000020149f42 RDI: 0000000000000014
RBP: 000000000000045e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f4970
R13: 00000000ffffffff R14: 00007f656c5316d4 R15: 0000000000000002
page:000000008b362fcc 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:483!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 15773 Comm: syz-executor3 Not tainted 4.15.0-rc2+ #152
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:put_page_testzero include/linux/mm.h:483 [inline]
RIP: 0010:__free_pages+0x118/0x150 mm/page_alloc.c:4284
RSP: 0018:ffff8801c3977790 EFLAGS: 00010203
RAX: 0000000000000000 RBX: ffffea00070e5dc0 RCX: 0000000000000000
RDX: 00000000001f0100 RSI: 1ffff1003872ee3e RDI: ffffed003872eee0
RBP: ffff8801c3977820 R08: 1ffff1003872ee00 R09: 0000000000000000
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff1003872eef3
R13: 1ffff1003872eef7 R14: 0000000000000000 R15: ffff8801c39777f8
FS:  00007f656c531700(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdd4c87fc8 CR3: 00000001c53c6000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 free_pages+0x51/0x90 mm/page_alloc.c:4298
 blkcipher_walk_done+0x767/0xde0 crypto/blkcipher.c:141
 encrypt+0x50a/0xaf0 crypto/salsa20_generic.c:208
 skcipher_crypt_blkcipher crypto/skcipher.c:622 [inline]
 skcipher_encrypt_blkcipher+0x213/0x310 crypto/skcipher.c:631
 crypto_skcipher_encrypt include/crypto/skcipher.h:445 [inline]
 _skcipher_recvmsg crypto/algif_skcipher.c:144 [inline]
 skcipher_recvmsg+0x9e8/0xf20 crypto/algif_skcipher.c:165
 sock_recvmsg_nosec net/socket.c:809 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:816
 sock_read_iter+0x361/0x560 net/socket.c:893
 call_read_iter include/linux/fs.h:1766 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 __vfs_read+0x6ad/0xa00 fs/read_write.c:413
 vfs_read+0x124/0x360 fs/read_write.c:447
 SYSC_read fs/read_write.c:573 [inline]
 SyS_read+0xef/0x220 fs/read_write.c:566
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007f656c530c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00000000007580d8 RCX: 0000000000452a39
RDX: 00000000000000be RSI: 0000000020149f42 RDI: 0000000000000014
RBP: 000000000000045e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f4970
R13: 00000000ffffffff R14: 00007f656c5316d4 R15: 0000000000000002
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 40 32 30 85 48 89 df e8 b8 61 0c 00 <0f> 0b 4c 89 ef 89 b5 74 ff ff ff e8 b8 f3 19 00 8b b5 74 ff ff 
RIP: put_page_testzero include/linux/mm.h:483 [inline] RSP: ffff8801c3977790
RIP: __free_pages+0x118/0x150 mm/page_alloc.c:4284 RSP: ffff8801c3977790
---[ end trace 0ce237f7715a12df ]---