KASAN: invalid-free in rcu_process_callbacks

[syzbot]

Hello,

syzbot hit the following crash on net-next commit
56455e0998dd3a8096eb3fdc2c8e870a29a77bef (Thu Mar 29 15:22:31 2018 +0000)
Merge branch 'master' of
git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=022ffded8e92e620d45e

Unfortunately, I don't have any reproducer for this crash yet.
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=6191276751847424
Kernel config:
https://syzkaller.appspot.com/x/.config?id=4372867303600475372
compiler: gcc (GCC) 7.1.1 20170620
CC: [douly...@cn.fujitsu.com h...@zytor.com jgr...@suse.com
linux-...@vger.kernel.org mi...@redhat.com pet...@infradead.org
tg...@linutronix.de ville....@linux.intel.com x...@kernel.org]

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Reported-by: syzbot+022ffd...@syzkaller.appspotmail.com
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netlink: 'syz-executor3': attribute type 29 has an invalid length.
netlink: 8 bytes leftover after parsing attributes in process
`syz-executor3'.
==================================================================
BUG: KASAN: double-free or invalid-free in __rcu_reclaim
kernel/rcu/rcu.h:167 [inline]
BUG: KASAN: double-free or invalid-free in rcu_do_batch
kernel/rcu/tree.c:2674 [inline]
BUG: KASAN: double-free or invalid-free in invoke_rcu_callbacks
kernel/rcu/tree.c:2933 [inline]
BUG: KASAN: double-free or invalid-free in __rcu_process_callbacks
kernel/rcu/tree.c:2900 [inline]
BUG: KASAN: double-free or invalid-free in
rcu_process_callbacks+0xe94/0x17f0 kernel/rcu/tree.c:2917

CPU: 0 PID: 31543 Comm: modprobe Not tainted 4.16.0-rc6+ #285
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x24d lib/dump_stack.c:53
print_address_description+0x73/0x250 mm/kasan/report.c:256
kasan_report_invalid_free+0x55/0x80 mm/kasan/report.c:336
__kasan_slab_free+0x145/0x170 mm/kasan/kasan.c:500
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
__cache_free mm/slab.c:3485 [inline]
kfree+0xd9/0x260 mm/slab.c:3800
__rcu_reclaim kernel/rcu/rcu.h:167 [inline]
rcu_do_batch kernel/rcu/tree.c:2674 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2933 [inline]
__rcu_process_callbacks kernel/rcu/tree.c:2900 [inline]
rcu_process_callbacks+0xe94/0x17f0 kernel/rcu/tree.c:2917
__do_softirq+0x2d7/0xb85 kernel/softirq.c:285
invoke_softirq kernel/softirq.c:365 [inline]
irq_exit+0x1cc/0x200 kernel/softirq.c:405
exiting_irq arch/x86/include/asm/apic.h:541 [inline]
smp_apic_timer_interrupt+0x16b/0x700 arch/x86/kernel/apic/apic.c:1052
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:857
</IRQ>
RIP: 0010:unwind_get_return_address+0x3d/0xa0
arch/x86/kernel/unwind_frame.c:19
RSP: 0018:ffff8801b29d75e0 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff12
RAX: 0000000000000001 RBX: ffff8801b29d7600 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffff8801b29d7d40 RDI: ffff8801b29d7600
RBP: ffff8801b29d75f0 R08: ffff8801b29d7640 R09: ffff8801cec02180
R10: 000000000000000b R11: ffffed003653aeca R12: 0000000000000000
R13: 0000000000000000 R14: ffff8801cec02180 R15: ffff8801da5c7840
__save_stack_trace+0x7e/0xd0 arch/x86/kernel/stacktrace.c:45
save_stack_trace+0x1a/0x20 arch/x86/kernel/stacktrace.c:60
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552
kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
slab_post_alloc_hook mm/slab.h:443 [inline]
slab_alloc mm/slab.c:3379 [inline]
kmem_cache_alloc+0x11b/0x760 mm/slab.c:3539
kmem_cache_zalloc include/linux/slab.h:691 [inline]
mmap_region+0x7ee/0x15a0 mm/mmap.c:1673
do_mmap+0x6c0/0xe00 mm/mmap.c:1483
do_mmap_pgoff include/linux/mm.h:2223 [inline]
vm_mmap_pgoff+0x1de/0x280 mm/util.c:355
SYSC_mmap_pgoff mm/mmap.c:1533 [inline]
SyS_mmap_pgoff+0x462/0x5f0 mm/mmap.c:1491
SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fb16f13a3ea
RSP: 002b:00007fffede4def8 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fb16f3429a8 RCX: 00007fb16f13a3ea
RDX: 0000000000000003 RSI: 0000000000005000 RDI: 00007fb16ef04000
RBP: 00007fffede4e250 R08: 0000000000000000 R09: 0000000000183000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007fffede4e338
R13: 0000000000000002 R14: 00007fffede4df70 R15: 00007fffede4df40

Allocated by task 31512:
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552
__do_kmalloc mm/slab.c:3705 [inline]
__kmalloc+0x162/0x760 mm/slab.c:3714
kmalloc include/linux/slab.h:517 [inline]
sk_prot_alloc+0x101/0x2a0 net/core/sock.c:1474
sk_alloc+0x105/0x1440 net/core/sock.c:1528
__netlink_create+0x6a/0x270 net/netlink/af_netlink.c:642
netlink_create+0x2fb/0x500 net/netlink/af_netlink.c:704
__sock_create+0x4d4/0x850 net/socket.c:1285
sock_create net/socket.c:1325 [inline]
SYSC_socket net/socket.c:1355 [inline]
SyS_socket+0xeb/0x1d0 net/socket.c:1335
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 28957:
save_stack+0x43/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
__kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
__cache_free mm/slab.c:3485 [inline]
kfree+0xd9/0x260 mm/slab.c:3800
sk_prot_free net/core/sock.c:1511 [inline]
__sk_destruct+0x750/0x920 net/core/sock.c:1593
sk_destruct+0x47/0x80 net/core/sock.c:1601
__sk_free+0xf1/0x2b0 net/core/sock.c:1612
sk_free+0x2a/0x40 net/core/sock.c:1623
sock_put include/net/sock.h:1660 [inline]
af_alg_release+0x5d/0x70 crypto/af_alg.c:126
sock_release+0x8d/0x1e0 net/socket.c:594
sock_close+0x16/0x20 net/socket.c:1149
__fput+0x327/0x7e0 fs/file_table.c:209
____fput+0x15/0x20 fs/file_table.c:243
task_work_run+0x199/0x270 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x9bb/0x1ad0 kernel/exit.c:865
do_group_exit+0x149/0x400 kernel/exit.c:968
get_signal+0x73a/0x16d0 kernel/signal.c:2469
do_signal+0x90/0x1e90 arch/x86/kernel/signal.c:809
exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
do_syscall_64+0x6ec/0x940 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff8801c1a95640
which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 1528 bytes inside of
2048-byte region [ffff8801c1a95640, ffff8801c1a95e40)
The buggy address belongs to the page:
page:ffffea000706a500 count:1 mapcount:0 mapping:ffff8801c1a94540 index:0x0
compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801c1a94540 0000000000000000 0000000100000003
raw: ffffea000737e5a0 ffffea00074879a0 ffff8801dac00c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8801c1a95b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8801c1a95b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ffff8801c1a95c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^
ffff8801c1a95c80: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8801c1a95d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.