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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+0xe4e/0xfc0 kernel/events/core.c:5917
Read of size 8 at addr ffff88817831fbe0 by task syz-executor.4/5664

CPU: 0 PID: 5664 Comm: syz-executor.4 Not tainted 4.14.128+ #10
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 5659:
 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]
 sock_wmalloc+0xa5/0xf0 net/core/sock.c:1928
 unix_stream_connect+0x1e4/0x1140 net/unix/af_unix.c:1244
 SYSC_connect net/socket.c:1655 [inline]
 SyS_connect+0x19b/0x280 net/socket.c:1636
 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292

Freed by task 5659:
 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]
 kfree_skb+0xc5/0x350 net/core/skbuff.c:663
 unix_stream_connect+0xfa0/0x1140 net/unix/af_unix.c:1386
 SYSC_connect net/socket.c:1655 [inline]
 SyS_connect+0x19b/0x280 net/socket.c:1636
 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292

The buggy address belongs to the object at ffff88817831fb80
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 96 bytes inside of
 512-byte region [ffff88817831fb80, ffff88817831fd80)
The buggy address belongs to the page:
page:ffffea0005e0c780 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 0000000000000000 0000000000000000 00000001000c000c
raw: ffffea0005e0c700 0000000500000005 ffff8881da802c00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88817831fa80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88817831fb00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88817831fb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff88817831fc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88817831fc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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