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BUG: KASAN: slab-out-of-bounds in perf_output_read_group kernel/events/core.c:5882 [inline]
BUG: KASAN: slab-out-of-bounds in perf_output_read+0xe58/0xfc0 kernel/events/core.c:5917
Read of size 8 at addr ffff888164debf08 by task syz-executor.2/5065

CPU: 1 PID: 5065 Comm: syz-executor.2 Not tainted 4.14.123+ #5
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 5065:
 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
 kmem_cache_alloc_trace+0x126/0x310 mm/slub.c:2750
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 alloc_perf_context+0x44/0xe0 kernel/events/core.c:3864
 find_get_context.isra.0+0x119/0x550 kernel/events/core.c:3953
 SYSC_perf_event_open kernel/events/core.c:10160 [inline]
 SyS_perf_event_open+0x9d3/0x2530 kernel/events/core.c:9988
 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292

Freed by task 3035:
 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
 tun_do_read+0x508/0x13a0 drivers/net/tun.c:1777
 tun_chr_read_iter+0xd9/0x1c0 drivers/net/tun.c:1791
 call_read_iter include/linux/fs.h:1779 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 __vfs_read+0x3fe/0x590 fs/read_write.c:413
 vfs_read+0x131/0x330 fs/read_write.c:447
 SYSC_read fs/read_write.c:577 [inline]
 SyS_read+0xc0/0x1a0 fs/read_write.c:570
 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292

The buggy address belongs to the object at ffff888164debb80
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 392 bytes to the right of
 512-byte region [ffff888164debb80, ffff888164debd80)
The buggy address belongs to the page:
page:ffffea0005937a80 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 0000000000000000 0000000000000000 00000001000c000c
raw: ffffea0007095080 0000000600000006 ffff8881d6402c00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888164debe00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888164debe80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888164debf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                      ^
 ffff888164debf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888164dec000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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