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BUG: KASAN: slab-out-of-bounds in cap_convert_nscap+0x501/0x610 security/commoncap.c:498
Read of size 4 at addr ffff8801dad89500 by task syz-executor4/14776

CPU: 0 PID: 14776 Comm: syz-executor4 Not tainted 4.15.0-rc4-mm1+ #49
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+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:355 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:413
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:433
 cap_convert_nscap+0x501/0x610 security/commoncap.c:498
 setxattr+0x365/0x400 fs/xattr.c:446
 SYSC_fsetxattr fs/xattr.c:508 [inline]
 SyS_fsetxattr+0x130/0x190 fs/xattr.c:497
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452ac9
RSP: 002b:00007fa5aef7cc58 EFLAGS: 00000212 ORIG_RAX: 00000000000000be
RAX: ffffffffffffffda RBX: 00007fa5aef7c950 RCX: 0000000000452ac9
RDX: 0000000020968000 RSI: 0000000020cf6fec RDI: 0000000000000013
RBP: 00007fa5aef7c940 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000212 R12: 00000000004b7433
R13: 00007fa5aef7cac8 R14: 00000000004b7445 R15: 0000000000000000

Allocated by task 14776:
 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:551
 __do_kmalloc_node mm/slab.c:3669 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3676
 kmalloc_node include/linux/slab.h:558 [inline]
 kvmalloc_node+0x99/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:541 [inline]
 setxattr+0x152/0x400 fs/xattr.c:435
 SYSC_fsetxattr fs/xattr.c:508 [inline]
 SyS_fsetxattr+0x130/0x190 fs/xattr.c:497
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 3123:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3485 [inline]
 kfree+0xd6/0x260 mm/slab.c:3800
 security_inode_init_security+0x1c3/0x390 security/security.c:494
 shmem_mknod+0x9b/0x1b0 mm/shmem.c:3012
 shmem_create+0x2b/0x40 mm/shmem.c:3067
 lookup_open+0x1217/0x1970 fs/namei.c:3218
 do_last fs/namei.c:3309 [inline]
 path_openat+0xd76/0x3530 fs/namei.c:3537
 do_filp_open+0x25b/0x3b0 fs/namei.c:3572
 do_sys_open+0x502/0x6d0 fs/open.c:1059
 SYSC_open fs/open.c:1077 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1072
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801dad89500
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8801dad89500, ffff8801dad89520)
The buggy address belongs to the page:
page:ffffea00076b6240 count:1 mapcount:0 mapping:ffff8801dad89000 index:0xffff8801dad89fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801dad89000 ffff8801dad89fc1 000000010000003c
raw: ffffea0007617da0 ffffea0007617aa0 ffff8801dac001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801dad89400: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801dad89480: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801dad89500: 03 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
                   ^
 ffff8801dad89580: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801dad89600: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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