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BUG: KASAN: slab-out-of-bounds in __list_add_valid+0x8f/0xac lib/list_debug.c:26
Read of size 8 at addr ffff8881be41a460 by task syz-executor2/6822

CPU: 1 PID: 6822 Comm: syz-executor2 Not tainted 4.20.0-rc6-next-20181214+ #171
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+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.4+0x9/0x1ff mm/kasan/report.c:187
 kasan_report.cold.5+0x1b/0x39 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 __list_add_valid+0x8f/0xac 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:2474 [inline]
 rdma_listen+0x6dc/0x990 drivers/infiniband/core/cma.c:3489
 ucma_listen+0x1a4/0x260 drivers/infiniband/core/ucma.c:1100
 ucma_write+0x365/0x460 drivers/infiniband/core/ucma.c:1689
 __vfs_write+0x119/0xab0 fs/read_write.c:485
 vfs_write+0x1fc/0x580 fs/read_write.c:549
 ksys_write+0x101/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457669
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fd7b2959c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457669
RDX: 0000000000000010 RSI: 0000000020000080 RDI: 000000000000000a
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd7b295a6d4
R13: 00000000004c5f10 R14: 00000000004da9d0 R15: 00000000ffffffff

Allocated by task 6753:
 save_stack+0x43/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 kasan_kmalloc+0xcb/0xd0 mm/kasan/common.c:482
 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:397
 kmem_cache_alloc+0x130/0x730 mm/slab.c:3541
 getname_flags+0xd0/0x590 fs/namei.c:140
 getname fs/namei.c:211 [inline]
 do_symlinkat+0x8b/0x2d0 fs/namei.c:4143
 __do_sys_symlink fs/namei.c:4173 [inline]
 __se_sys_symlink fs/namei.c:4171 [inline]
 __x64_sys_symlink+0x59/0x80 fs/namei.c:4171
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6753:
 save_stack+0x43/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452
 __cache_free mm/slab.c:3485 [inline]
 kmem_cache_free+0x83/0x290 mm/slab.c:3747
 putname+0xf2/0x130 fs/namei.c:261
 do_symlinkat+0x18c/0x2d0 fs/namei.c:4161
 __do_sys_symlink fs/namei.c:4173 [inline]
 __se_sys_symlink fs/namei.c:4171 [inline]
 __x64_sys_symlink+0x59/0x80 fs/namei.c:4171
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881be41ac00
 which belongs to the cache names_cache of size 4096
The buggy address is located 1952 bytes to the left of
 4096-byte region [ffff8881be41ac00, ffff8881be41bc00)
The buggy address belongs to the page:
page:ffffea0006f90680 count:1 mapcount:0 mapping:ffff8881da986e00 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea0006e78588 ffffea0007338588 ffff8881da986e00
raw: 0000000000000000 ffff8881be41ac00 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881be41a300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881be41a380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881be41a400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                       ^
 ffff8881be41a480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881be41a500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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