================================================================== 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 ffff8881c8128608 by task syz-executor.2/8387 CPU: 0 PID: 8387 Comm: syz-executor.2 Not tainted 4.14.120+ #9 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 190: 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] kobject_uevent_env+0x571/0xc60 lib/kobject_uevent.c:476 Freed by task 190: 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+0x4ad/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_broadcast_filtered+0x2b3/0x9d0 net/netlink/af_netlink.c:1488 kobject_uevent_env+0x6ba/0xc60 lib/kobject_uevent.c:492 The buggy address belongs to the object at ffff8881c8128500 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 264 bytes inside of 512-byte region [ffff8881c8128500, ffff8881c8128700) The buggy address belongs to the page: page:ffffea0007204a00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 0000000000000000 0000000000000000 00000001000c000c raw: ffffea000715e300 0000000700000007 ffff8881da802c00 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881c8128500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881c8128580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881c8128600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881c8128680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881c8128700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================