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BUG: KASAN: slab-out-of-bounds in __list_add_valid+0x8f/0xb0 lib/list_debug.c:26
Read of size 8 at addr ffff8801b1a74cd8 by task syz-executor4/7317

CPU: 0 PID: 7317 Comm: syz-executor4 Not tainted 4.17.0-rc7+ #104
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: 0023:0xf7f84cb9
RSP: 002b:00000000f5f800ac EFLAGS: 00000282 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000015 RCX: 00000000200088c0
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4534:
 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]
 user_path_mountpoint_at+0x27/0x40 fs/namei.c:2699
 ksys_umount+0x1be/0x1280 fs/namespace.c:1700
 __do_sys_umount fs/namespace.c:1726 [inline]
 __se_sys_umount fs/namespace.c:1724 [inline]
 __ia32_sys_umount+0x53/0x80 fs/namespace.c:1724
 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 4534:
 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
 filename_mountpoint+0x34e/0x440 fs/namei.c:2677
 user_path_mountpoint_at+0x37/0x40 fs/namei.c:2699
 ksys_umount+0x1be/0x1280 fs/namespace.c:1700
 __do_sys_umount fs/namespace.c:1726 [inline]
 __se_sys_umount fs/namespace.c:1724 [inline]
 __ia32_sys_umount+0x53/0x80 fs/namespace.c:1724
 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 ffff8801b1a74d00
 which belongs to the cache names_cache of size 4096
The buggy address is located 40 bytes to the left of
 4096-byte region [ffff8801b1a74d00, ffff8801b1a75d00)
The buggy address belongs to the page:
page:ffffea0006c69d00 count:1 mapcount:0 mapping:ffff8801b1a74d00 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801b1a74d00 0000000000000000 0000000100000001
raw: ffffea000628cf20 ffffea0006282820 ffff8801da988dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b1a74b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801b1a74c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801b1a74c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                    ^
 ffff8801b1a74d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801b1a74d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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