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BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry+0x2ef/0x340 fs/ext4/dir.c:86
Read of size 1 at addr ffff8880562c8001 by task syz-executor.3/21816

CPU: 0 PID: 21816 Comm: syz-executor.3 Not tainted 4.14.184-syzkaller #0
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+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393
 __ext4_check_dir_entry+0x2ef/0x340 fs/ext4/dir.c:86
 ext4_readdir+0x819/0x27e0 fs/ext4/dir.c:240
 iterate_dir+0x1a0/0x5e0 fs/readdir.c:52
 SYSC_getdents fs/readdir.c:269 [inline]
 SyS_getdents+0x132/0x260 fs/readdir.c:250
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca59
RSP: 002b:00007f62f6c6fc78 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00000000004dcf60 RCX: 000000000045ca59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000000f6 R14: 00000000004c3a00 R15: 00007f62f6c706d4

Allocated by task 6353:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3682 [inline]
 __kmalloc_node+0x4c/0x70 mm/slab.c:3689
 kmalloc_node include/linux/slab.h:530 [inline]
 kvmalloc_node+0x46/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:531 [inline]
 xt_alloc_table_info+0x6a/0xe0 net/netfilter/x_tables.c:1062
 do_replace net/ipv4/netfilter/ip_tables.c:1127 [inline]
 do_ipt_set_ctl+0x1b1/0x39d net/ipv4/netfilter/ip_tables.c:1674
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline]
 ip_setsockopt+0x94/0xb0 net/ipv4/ip_sockglue.c:1240
 tcp_setsockopt net/ipv4/tcp.c:2828 [inline]
 tcp_setsockopt+0x7b/0xc0 net/ipv4/tcp.c:2822
 SYSC_setsockopt net/socket.c:1865 [inline]
 SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 6353:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 kvfree+0x45/0x50 mm/util.c:416
 __do_replace+0x3f0/0x570 net/ipv4/netfilter/ip_tables.c:1088
 do_replace net/ipv4/netfilter/ip_tables.c:1142 [inline]
 do_ipt_set_ctl+0x255/0x39d net/ipv4/netfilter/ip_tables.c:1674
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline]
 ip_setsockopt+0x94/0xb0 net/ipv4/ip_sockglue.c:1240
 tcp_setsockopt net/ipv4/tcp.c:2828 [inline]
 tcp_setsockopt+0x7b/0xc0 net/ipv4/tcp.c:2822
 SYSC_setsockopt net/socket.c:1865 [inline]
 SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880562c8040
 which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 63 bytes to the left of
 1024-byte region [ffff8880562c8040, ffff8880562c8440)
The buggy address belongs to the page:
page:ffffea000158b200 count:1 mapcount:0 mapping:ffff8880562c8040 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880562c8040 0000000000000000 0000000100000007
raw: ffffea00016237a0 ffffea000158b2a0 ffff8880aa800ac0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880562c7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880562c7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880562c8000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                   ^
 ffff8880562c8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880562c8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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