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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 ffff8881b5e48388 by task syz-executor.5/30370

CPU: 1 PID: 30370 Comm: syz-executor.5 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 29435:
 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
 __kmalloc+0x143/0x340 mm/slub.c:3760
 __kmalloc_node include/linux/slab.h:356 [inline]
 kmalloc_node include/linux/slab.h:530 [inline]
 kvmalloc_node+0x43/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:531 [inline]
 kvzalloc include/linux/mm.h:539 [inline]
 netif_alloc_netdev_queues net/core/dev.c:7534 [inline]
 alloc_netdev_mqs+0x5e8/0xb70 net/core/dev.c:8127

Freed by task 1804:
 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
 kvfree+0x55/0x80 mm/util.c:416
 netif_free_tx_queues net/core/dev.c:7522 [inline]
 free_netdev+0x55/0x3a0 net/core/dev.c:8174
 netdev_run_todo+0x5ab/0x740 net/core/dev.c:7932

The buggy address belongs to the object at ffff8881b5e48280
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 264 bytes inside of
 512-byte region [ffff8881b5e48280, ffff8881b5e48480)
The buggy address belongs to the page:
page:ffffea0006d79200 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 0000000000000000 0000000000000000 00000001000c000c
raw: dead000000000100 dead000000000200 ffff8881da802c00 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881b5e48280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881b5e48300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881b5e48380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff8881b5e48400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881b5e48480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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