Message-ID: <001a11441d867b940f055c4c0b40@google.com>
Date:   Tue, 24 Oct 2017 07:49:23 -0700
From:   syzbot 
        <bot+a004c8dcbae7c160bf1bbd6e6af2e9cf4fa54f84@...kaller.appspotmail.com>
To:     davem@...emloft.net, linux-kernel@...r.kernel.org,
        linux-sctp@...r.kernel.org, netdev@...r.kernel.org,
        nhorman@...driver.com, syzkaller-bugs@...glegroups.com,
        vyasevich@...il.com
Subject: WARNING in refcount_sub_and_test

Hello,

syzkaller hit the following crash on  
49ca1943a7adb429b11b8e05d81bc821694b76c7
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


refcount_t: underflow; use-after-free.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 2992 at lib/refcount.c:186  
refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:186
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 2992 Comm: syzkaller263121 Not tainted 4.14.0-rc5+ #91
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:16 [inline]
  dump_stack+0x194/0x257 lib/dump_stack.c:52
  panic+0x1e4/0x417 kernel/panic.c:181
  __warn+0x1c4/0x1d9 kernel/panic.c:542
  report_bug+0x211/0x2d0 lib/bug.c:183
  fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178
  do_trap_no_signal arch/x86/kernel/traps.c:212 [inline]
  do_trap+0x260/0x390 arch/x86/kernel/traps.c:261
  do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311
  invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
RIP: 0010:refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:186
RSP: 0018:ffff8801d1f4e9c8 EFLAGS: 00010282
RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000026 RSI: 1ffff1003a3e9cf9 RDI: ffffed003a3e9d2d
RBP: ffff8801d1f4ea58 R08: 0000000000000000 R09: 1ffff1003a3e9ccb
R10: ffff8801d1f4e7f8 R11: ffffffff85b2cb78 R12: 1ffff1003a3e9d3a
R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d1d16a3c
  sctp_wfree+0x183/0x620 net/sctp/socket.c:7927
  skb_release_head_state+0x124/0x200 net/core/skbuff.c:616
  skb_release_all+0x15/0x60 net/core/skbuff.c:629
  __kfree_skb net/core/skbuff.c:645 [inline]
  consume_skb+0x153/0x490 net/core/skbuff.c:705
  sctp_chunk_destroy net/sctp/sm_make_chunk.c:1437 [inline]
  sctp_chunk_put+0x29c/0x420 net/sctp/sm_make_chunk.c:1464
  sctp_chunk_free+0x53/0x60 net/sctp/sm_make_chunk.c:1451
  __sctp_outq_teardown+0xa5b/0x1230 net/sctp/outqueue.c:273
  sctp_outq_free+0x15/0x20 net/sctp/outqueue.c:293
  sctp_association_free+0x2d0/0x930 net/sctp/associola.c:357
  sctp_cmd_delete_tcb net/sctp/sm_sideeffect.c:920 [inline]
  sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1336 [inline]
  sctp_side_effects net/sctp/sm_sideeffect.c:1203 [inline]
  sctp_do_sm+0x271b/0x6a30 net/sctp/sm_sideeffect.c:1174
  sctp_primitive_SHUTDOWN+0xa0/0xd0 net/sctp/primitive.c:104
  sctp_close+0x3c6/0x980 net/sctp/socket.c:1533
  inet_release+0xed/0x1c0 net/ipv4/af_inet.c:426
  sock_release+0x8d/0x1e0 net/socket.c:597
  sock_close+0x16/0x20 net/socket.c:1126
  __fput+0x327/0x7e0 fs/file_table.c:210
  ____fput+0x15/0x20 fs/file_table.c:244
  task_work_run+0x199/0x270 kernel/task_work.c:112
  get_signal+0x1343/0x16d0 kernel/signal.c:2164
  do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:808
  exit_to_usermode_loop+0x214/0x310 arch/x86/entry/common.c:158
  prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
  syscall_return_slowpath+0x42f/0x510 arch/x86/entry/common.c:266
  entry_SYSCALL_64_fastpath+0xbc/0xbe
RIP: 0033:0x446539
RSP: 002b:00007f402614bdc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000120
RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 0000000000446539
RDX: 0000000020137ffc RSI: 0000000020b53ff0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007f402614c700 R09: 00007f402614c700
R10: 0000000000080000 R11: 0000000000000202 R12: 0000000000000000
R13: 00000000007efe7f R14: 00007f402614c9c0 R15: 0000000000000000
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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