================================================================== 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 ffff8881d0ce6608 by task syz-executor749/1887 CPU: 0 PID: 1887 Comm: syz-executor749 Not tainted 4.14.129+ #11 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 1885: 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 include/linux/slab.h:493 [inline] kzalloc include/linux/slab.h:661 [inline] rb_alloc+0x7b/0x490 kernel/events/ring_buffer.c:750 perf_mmap+0xc13/0x1390 kernel/events/core.c:5467 call_mmap include/linux/fs.h:1793 [inline] mmap_region+0x7c9/0xf00 mm/mmap.c:1732 do_mmap+0x548/0xb80 mm/mmap.c:1510 do_mmap_pgoff include/linux/mm.h:2180 [inline] vm_mmap_pgoff+0x177/0x1c0 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1560 [inline] SyS_mmap_pgoff+0xf4/0x1b0 mm/mmap.c:1518 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292 Freed by task 1887: 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 __rcu_reclaim kernel/rcu/rcu.h:195 [inline] rcu_do_batch kernel/rcu/tree.c:2699 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline] rcu_process_callbacks+0x56f/0xf40 kernel/rcu/tree.c:2946 __do_softirq+0x234/0x9ca kernel/softirq.c:288 The buggy address belongs to the object at ffff8881d0ce6500 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 264 bytes inside of 512-byte region [ffff8881d0ce6500, ffff8881d0ce6700) The buggy address belongs to the page: page:ffffea0007433980 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 0000000000000000 0000000000000000 00000001800c000c raw: ffffea00073a9b00 0000000600000006 ffff8881da802c00 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881d0ce6500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d0ce6580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881d0ce6600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d0ce6680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d0ce6700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================