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SubjectKASAN: use-after-free Read in __list_add_valid (5)
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Hello,

syzbot hit the following crash on upstream commit
bcfc1f4554662d8f2429ac8bd96064a59c149754 (Sat Mar 24 16:50:12 2018 +0000)
Merge tag 'pinctrl-v4.16-3' of
git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=db1c219466daac1083df

So far this crash happened 4 times on upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5164223906709504
syzkaller reproducer:
https://syzkaller.appspot.com/x/repro.syz?id=5357898477600768
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=5549124782915584
Kernel config:
https://syzkaller.appspot.com/x/.config?id=-5034017172441945317
compiler: gcc (GCC) 7.1.1 20170620

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+db1c219466daac1083df@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for
details.
If you forward the report, please keep this part and the footer.

IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
==================================================================
BUG: KASAN: use-after-free in __list_add_valid+0xc6/0xd0 lib/list_debug.c:26
IPVS: ftp: loaded support on port[0] = 21
Read of size 8 at addr ffff8801ca8adcd8 by task syzkaller401155/4288

CPU: 0 PID: 4288 Comm: syzkaller401155 Not tainted 4.16.0-rc6+ #365
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+0x194/0x24d lib/dump_stack.c:53
print_address_description+0x73/0x250 mm/kasan/report.c:256
IPVS: ftp: loaded support on port[0] = 21
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report+0x23c/0x360 mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
__list_add_valid+0xc6/0xd0 lib/list_debug.c:26
__list_add include/linux/list.h:60 [inline]
list_add_tail include/linux/list.h:93 [inline]
cma_listen_on_all drivers/infiniband/core/cma.c:2309 [inline]
rdma_listen+0x581/0x8e0 drivers/infiniband/core/cma.c:3333
ucma_listen+0x172/0x1f0 drivers/infiniband/core/ucma.c:1074
ucma_write+0x2d6/0x3d0 drivers/infiniband/core/ucma.c:1649
IPVS: ftp: loaded support on port[0] = 21
__vfs_write+0xef/0x970 fs/read_write.c:480
IPVS: ftp: loaded support on port[0] = 21
vfs_write+0x189/0x510 fs/read_write.c:544
SYSC_write fs/read_write.c:589 [inline]
SyS_write+0xef/0x220 fs/read_write.c:581
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
IPVS: ftp: loaded support on port[0] = 21
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x44a9e9
RSP: 002b:00007f94303f3da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000006e29fc RCX: 000000000044a9e9
RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00000000006e29f8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 2f646e6162696e69
R13: 666e692f7665642f R14: 7073642f7665642f R15: 0000000000000009

Allocated by task 4284:
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
kmem_cache_alloc_trace+0x136/0x740 mm/slab.c:3607
kmalloc include/linux/slab.h:512 [inline]
kzalloc include/linux/slab.h:701 [inline]
rdma_create_id+0xd0/0x630 drivers/infiniband/core/cma.c:787
ucma_create_id+0x35f/0x920 drivers/infiniband/core/ucma.c:480
ucma_write+0x2d6/0x3d0 drivers/infiniband/core/ucma.c:1649
__vfs_write+0xef/0x970 fs/read_write.c:480
vfs_write+0x189/0x510 fs/read_write.c:544
SYSC_write fs/read_write.c:589 [inline]
SyS_write+0xef/0x220 fs/read_write.c:581
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 4284:
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
rdma_destroy_id+0x821/0xda0 drivers/infiniband/core/cma.c:1691
ucma_close+0x100/0x2f0 drivers/infiniband/core/ucma.c:1728
__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 ffff8801ca8adb00
which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 472 bytes inside of
1024-byte region [ffff8801ca8adb00, ffff8801ca8adf00)
The buggy address belongs to the page:
page:ffffea00072a2b00 count:1 mapcount:0 mapping:ffff8801ca8ac000 index:0x0
compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801ca8ac000 0000000000000000 0000000100000007
raw: ffffea00072969a0 ffffea00072c5d20 ffff8801dac00ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8801ca8adb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801ca8adc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8801ca8adc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801ca8add00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801ca8add80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a dumb bot. It may contain errors.
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