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BUG: KASAN: use-after-free in perf_output_read_group kernel/events/core.c:5882 [inline]
BUG: KASAN: use-after-free in perf_output_read+0xe58/0xfc0 kernel/events/core.c:5917
Read of size 8 at addr ffff8881cb002b08 by task syz-executor.4/13523

CPU: 0 PID: 13523 Comm: syz-executor.4 Not tainted 4.14.123+ #1
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x10e lib/dump_stack.c:53
 print_address_description+0x60/0x226 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+0xae/0x2d5 mm/kasan/report.c:393

Allocated by task 13524:
 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
 slab_post_alloc_hook mm/slab.h:442 [inline]
 slab_alloc_node mm/slub.c:2723 [inline]
 slab_alloc mm/slub.c:2731 [inline]
 __kmalloc_track_caller+0xf1/0x310 mm/slub.c:4288
 __kmalloc_reserve.isra.0+0x2d/0xc0 net/core/skbuff.c:137
 __alloc_skb+0x105/0x550 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:980 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1158 [inline]
 netlink_sendmsg+0x94b/0xbe0 net/netlink/af_netlink.c:1852
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb7/0x100 net/socket.c:656
 ___sys_sendmsg+0x752/0x890 net/socket.c:2062
 __sys_sendmsg+0xb6/0x150 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292

Freed by task 13524:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:524
 slab_free_hook mm/slub.c:1389 [inline]
 slab_free_freelist_hook mm/slub.c:1410 [inline]
 slab_free mm/slub.c:2966 [inline]
 kfree+0xf5/0x310 mm/slub.c:3897
 skb_free_head+0x83/0xa0 net/core/skbuff.c:554
 skb_release_data+0x4ae/0x730 net/core/skbuff.c:574
 skb_release_all+0x46/0x60 net/core/skbuff.c:631
 __kfree_skb net/core/skbuff.c:645 [inline]
 consume_skb+0xbe/0x340 net/core/skbuff.c:705
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x480/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x65d/0xbe0 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb7/0x100 net/socket.c:656
 ___sys_sendmsg+0x752/0x890 net/socket.c:2062
 __sys_sendmsg+0xb6/0x150 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292

The buggy address belongs to the object at ffff8881cb002a00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 264 bytes inside of
 512-byte region [ffff8881cb002a00, ffff8881cb002c00)
The buggy address belongs to the page:
page:ffffea00072c0080 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 0000000000000000 0000000000000000 00000001000c000c
raw: ffffea000719f480 0000000c00000003 ffff8881d6402c00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881cb002a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881cb002a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881cb002b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff8881cb002b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881cb002c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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