suspicious RCU usage at ./include/trace/events/kmem.h:LINE

[syzbot]

Hello,

syzkaller hit the following crash on
1d3b78bbc6e983fabb3fbf91b76339bf66e4a12c
git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
C reproducer is attached
syzkaller reproducer is attached. See https://goo.gl/kgGztJ
for information about syzkaller reproducers



=============================
WARNING: suspicious RCU usage
4.14.0+ #192 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 syzkaller215525/3051:
#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: 3051 Comm: syzkaller215525 Not tainted 4.14.0+ #192
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+0x20e/0x540 arch/x86/crypto/salsa20_glue.c:79
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
skcipher_recvmsg_nokey+0x60/0x80 crypto/algif_skcipher.c:283
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: 0033:0x43fe59
RSP: 002b:00007fff42311cc8 EFLAGS: 00000217 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fe59
RDX: 0000000000002000 RSI: 0000000020222fc8 RDI: 0000000000000004
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000000217 R12: 00000000004017c0
R13: 0000000000401850 R14: 0000000000000000 R15: 0000000000000000
BUG: unable to handle kernel NULL pointer dereference at 0000000000000074
IP: virt_to_cache mm/slab.c:400 [inline]
IP: kfree+0xb2/0x250 mm/slab.c:3802
PGD 1ccc28067 P4D 1ccc28067 PUD 1ccd52067 PMD 0
Oops: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 3051 Comm: syzkaller215525 Not tainted 4.14.0+ #192
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
task: ffff8801cd642100 task.stack: ffff8801cd768000
RIP: 0010:virt_to_cache mm/slab.c:400 [inline]
RIP: 0010:kfree+0xb2/0x250 mm/slab.c:3802
RSP: 0018:ffff8801cd76f750 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8801cd76f918 RCX: ffffffffffffffff
RDX: ffffea000735dbc0 RSI: 0000000000000000 RDI: ffff8801cd76f918
RBP: ffff8801cd76f770 R08: 1ffff10039aede9c R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000286
R13: 0000000000000000 R14: ffff8801cd76f918 R15: ffff8801cd76f880
FS: 00000000017ea880(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000074 CR3: 00000001ccecc000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
blkcipher_walk_done+0x72b/0xde0 crypto/blkcipher.c:139
encrypt+0x20e/0x540 arch/x86/crypto/salsa20_glue.c:79
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
skcipher_recvmsg_nokey+0x60/0x80 crypto/algif_skcipher.c:283
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: 0033:0x43fe59
RSP: 002b:00007fff42311cc8 EFLAGS: 00000217 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fe59
RDX: 0000000000002000 RSI: 0000000020222fc8 RDI: 0000000000000004
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000010 R11: 0000000000000217 R12: 00000000004017c0
R13: 0000000000401850 R14: 0000000000000000 R15: 0000000000000000
Code: c2 48 b8 00 00 00 00 00 ea ff ff 48 89 df 48 c1 ea 0c 48 c1 e2 06 48
01 c2 48 8b 42 20 48 8d 48 ff a8 01 48 0f 45 d1 4c 8b 6a 30 <49> 63 75 74
e8 e5 73 af ff 48 89 de 4c 89 ef 4c 8b 75 08 e8 06
RIP: virt_to_cache mm/slab.c:400 [inline] RSP: ffff8801cd76f750
RIP: kfree+0xb2/0x250 mm/slab.c:3802 RSP: ffff8801cd76f750
CR2: 0000000000000074
---[ end trace e64159c1a33afd49 ]---


---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to syzk...@googlegroups.com.
Please credit me with: Reported-by: syzbot <syzk...@googlegroups.com>

syzbot will keep track of this bug report.
Once a fix for this bug is committed, please reply to this email with:
#syz fix: exact-commit-title
If you want to test a patch for this bug, please reply with:
#syz test: git://repo/address.git branch
and provide the patch inline or as an attachment.
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug
report.
Note: all commands must start from beginning of the line in the email body.

[Eric Biggers]

#syz dup: WARNING: suspicious RCU usage (3)