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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 ffff8801d864c6c0 by task syz-executor5/26347

CPU: 0 PID: 26347 Comm: syz-executor5 Not tainted 4.15.0-rc5+ #153
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:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429
 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
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129
RIP: 0023:0xf7f5bc79
RSP: 002b:00000000f775708c EFLAGS: 00000296 ORIG_RAX: 00000000000000e4
RAX: ffffffffffffffda RBX: 0000000000000014 RCX: 00000000204c3000
RDX: 000000002048bfff RSI: 0000000000000001 RDI: 0000000000000002
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 26347:
 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:3672 [inline]
 __kmalloc_node+0x47/0x70 mm/slab.c:3679
 kmalloc_node include/linux/slab.h:541 [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
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129

Freed by task 3424:
 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:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 simple_xattrs_free include/linux/xattr.h:97 [inline]
 shmem_evict_inode+0x1b0/0xb30 mm/shmem.c:1083
 evict+0x481/0x920 fs/inode.c:553
 iput_final fs/inode.c:1515 [inline]
 iput+0x7b9/0xaf0 fs/inode.c:1542
 dentry_unlink_inode+0x4b0/0x5e0 fs/dcache.c:375
 d_delete+0x1a7/0x250 fs/dcache.c:2367
 vfs_rmdir+0x32d/0x410 fs/namei.c:3871
 do_rmdir+0x4c8/0x5f0 fs/namei.c:3919
 SYSC_rmdir fs/namei.c:3937 [inline]
 SyS_rmdir+0x1a/0x20 fs/namei.c:3935
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x54/0x63 arch/x86/entry/entry_64_compat.S:129

The buggy address belongs to the object at ffff8801d864c6c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8801d864c6c0, ffff8801d864c6e0)
The buggy address belongs to the page:
page:0000000024ff6c9c count:1 mapcount:0 mapping:00000000df9edfe7 index:0xffff8801d864cfc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d864c000 ffff8801d864cfc1 000000010000002b
raw: ffffea0007618e20 ffffea0007615d60 ffff8801dac001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d864c580: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d864c600: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801d864c680: fb fb fb fb fc fc fc fc 01 fc fc fc fc fc fc fc
                                           ^
 ffff8801d864c700: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d864c780: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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