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BUG: KASAN: slab-out-of-bounds in cap_inode_getsecurity+0x597/0x6e0 security/commoncap.c:408
Read of size 4 at addr ffff8801cb4ddd00 by task syz-executor2/8016

CPU: 1 PID: 8016 Comm: syz-executor2 Not tainted 4.15.0-rc6-next-20180103+ #87
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+0x137/0x198 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_inode_getsecurity+0x597/0x6e0 security/commoncap.c:408
 security_inode_getsecurity+0xcd/0x110 security/security.c:809
 xattr_getsecurity+0x119/0x130 fs/xattr.c:240
 vfs_getxattr+0xc8/0x110 fs/xattr.c:333
 getxattr+0x232/0x2a0 fs/xattr.c:540
 path_getxattr+0xcb/0x130 fs/xattr.c:568
 SYSC_getxattr fs/xattr.c:580 [inline]
 SyS_getxattr+0x33/0x40 fs/xattr.c:577
 entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x452ac9
RSP: 002b:00007f34e9e00c58 EFLAGS: 00000212 ORIG_RAX: 00000000000000bf
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9
RDX: 0000000020227f74 RSI: 0000000020b29f57 RDI: 0000000020fb6000
RBP: 0000000000000059 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee8f8
R13: 00000000ffffffff R14: 00007f34e9e016d4 R15: 0000000000000000

Allocated by task 8016:
 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 mm/slab.c:3705 [inline]
 __kmalloc_track_caller+0x15e/0x760 mm/slab.c:3720
 __do_krealloc mm/slab_common.c:1449 [inline]
 krealloc+0x65/0xc0 mm/slab_common.c:1496
 vfs_getxattr_alloc+0x177/0x270 fs/xattr.c:290
 cap_inode_getsecurity+0xe1/0x6e0 security/commoncap.c:399
 security_inode_getsecurity+0xcd/0x110 security/security.c:809
 xattr_getsecurity+0x119/0x130 fs/xattr.c:240
 vfs_getxattr+0xc8/0x110 fs/xattr.c:333
 getxattr+0x232/0x2a0 fs/xattr.c:540
 path_getxattr+0xcb/0x130 fs/xattr.c:568
 SYSC_getxattr fs/xattr.c:580 [inline]
 SyS_getxattr+0x33/0x40 fs/xattr.c:577
 entry_SYSCALL_64_fastpath+0x23/0x9a

Freed by task 4660:
 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
 selinux_cred_free+0x48/0x70 security/selinux/hooks.c:3815
 security_cred_free+0x48/0x80 security/security.c:995
 put_cred_rcu+0x62/0x2c0 kernel/cred.c:117
 __rcu_reclaim kernel/rcu/rcu.h:172 [inline]
 rcu_do_batch kernel/rcu/tree.c:2675 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2934 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2901 [inline]
 rcu_process_callbacks+0x5cf/0x1200 kernel/rcu/tree.c:2918
 __do_softirq+0x23f/0x99f kernel/softirq.c:285

The buggy address belongs to the object at ffff8801cb4ddd00
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8801cb4ddd00, ffff8801cb4ddd20)
The buggy address belongs to the page:
page:ffffea00072d3740 count:1 mapcount:0 mapping:ffff8801cb4dd000 index:0xffff8801cb4ddfc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801cb4dd000 ffff8801cb4ddfc1 000000010000003f
raw: ffffea00072ed860 ffffea00072b1c60 ffff8801db0001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cb4ddc00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801cb4ddc80: 00 00 00 00 fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801cb4ddd00: 01 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
                   ^
 ffff8801cb4ddd80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801cb4dde00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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