KASAN: slab-out-of-bounds Read in rdma_listen

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: c1c07416cdd4 Merge tag 'kbuild-fixes-v4.17' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=126e9a97800000
kernel config: https://syzkaller.appspot.com/x/.config?x=5a1dc06635c10d27
dashboard link: https://syzkaller.appspot.com/bug?extid=2a5c4f097bfdb814b89e
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
userspace arch: i386
CC: [dan...@mellanox.com dled...@redhat.com j...@ziepe.ca
le...@kernel.org linux-...@vger.kernel.org linux...@vger.kernel.org
mo...@mellanox.com pa...@mellanox.com sw...@opengridcomputing.com]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2a5c4f...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in __list_add_valid+0x8f/0xb0
lib/list_debug.c:26
Read of size 8 at addr ffff88018ff5b318 by task syz-executor7/15840

CPU: 0 PID: 15840 Comm: syz-executor7 Not tainted 4.17.0-rc3+ #59
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1b9/0x294 lib/dump_stack.c:113
print_address_description+0x6c/0x20b mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
__list_add_valid+0x8f/0xb0 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:2301 [inline]
rdma_listen+0x6cd/0x980 drivers/infiniband/core/cma.c:3327
ucma_listen+0x19c/0x250 drivers/infiniband/core/ucma.c:1096
ucma_write+0x328/0x410 drivers/infiniband/core/ucma.c:1676
__vfs_write+0x10b/0x960 fs/read_write.c:485
vfs_write+0x1f8/0x560 fs/read_write.c:549
ksys_write+0xf9/0x250 fs/read_write.c:598
__do_sys_write fs/read_write.c:610 [inline]
__se_sys_write fs/read_write.c:607 [inline]
__ia32_sys_write+0x71/0xb0 fs/read_write.c:607
do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline]
do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fd5cb9
RSP: 002b:00000000f5fd10ac EFLAGS: 00000282 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4561:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
getname_flags+0xd0/0x5a0 fs/namei.c:140
getname fs/namei.c:211 [inline]
__do_sys_unlink fs/namei.c:4080 [inline]
__se_sys_unlink fs/namei.c:4078 [inline]
__ia32_sys_unlink+0x34/0x50 fs/namei.c:4078
do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline]
do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 4561:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
putname+0xf2/0x130 fs/namei.c:261
do_unlinkat+0x22e/0xa10 fs/namei.c:4054
__do_sys_unlink fs/namei.c:4080 [inline]
__se_sys_unlink fs/namei.c:4078 [inline]
__ia32_sys_unlink+0x41/0x50 fs/namei.c:4078
do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline]
do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

The buggy address belongs to the object at ffff88018ff5a200
which belongs to the cache names_cache of size 4096
The buggy address is located 280 bytes to the right of
4096-byte region [ffff88018ff5a200, ffff88018ff5b200)
The buggy address belongs to the page:
page:ffffea00063fd680 count:1 mapcount:0 mapping:ffff88018ff5a200 index:0x0
compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff88018ff5a200 0000000000000000 0000000100000001
raw: ffffea0006394120 ffffea0006d2b120 ffff8801da988dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88018ff5b200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88018ff5b280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff88018ff5b300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88018ff5b380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88018ff5b400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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[Dmitry Vyukov]

#syz upstream

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