================================================================== BUG: KASAN: use-after-free in perf_output_read_group kernel/events/core.c:5874 [inline] BUG: KASAN: use-after-free in perf_output_read+0xe4d/0xfb0 kernel/events/core.c:5909 Read of size 8 at addr ffff8801cc963a08 by task syz-executor1/30065 CPU: 1 PID: 30065 Comm: syz-executor1 Not tainted 4.14.76+ #20 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 print_address_description+0x60/0x22b mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report.cold.6+0x11b/0x2dd mm/kasan/report.c:409 perf_output_read_group kernel/events/core.c:5874 [inline] perf_output_read+0xe4d/0xfb0 kernel/events/core.c:5909 perf_output_sample+0x10dd/0x1780 kernel/events/core.c:5951 __perf_event_output kernel/events/core.c:6261 [inline] perf_event_output_forward+0x121/0x230 kernel/events/core.c:6274 __perf_event_overflow+0x116/0x320 kernel/events/core.c:7510 perf_swevent_overflow+0x166/0x1f0 kernel/events/core.c:7586 perf_swevent_event+0x19c/0x270 kernel/events/core.c:7619 do_perf_sw_event kernel/events/core.c:7727 [inline] ___perf_sw_event+0x296/0x480 kernel/events/core.c:7758 __perf_sw_event+0x3f/0x70 kernel/events/core.c:7770 perf_sw_event include/linux/perf_event.h:1041 [inline] __do_page_fault+0x77f/0xb60 arch/x86/mm/fault.c:1466 page_fault+0x22/0x50 arch/x86/entry/entry_64.S:1104 RIP: 0010:fault_in_pages_readable include/linux/pagemap.h:613 [inline] RIP: 0010:iov_iter_fault_in_readable+0x2b9/0x370 lib/iov_iter.c:421 RSP: 0018:ffff8801c618f9f8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 000000000000007f RCX: 0000000000040000 RDX: ffffffff81b56253 RSI: ffffc9000177a000 RDI: ffff8801c618fcf8 RBP: 1ffff10038c31f40 R08: 0000000000001000 R09: ffffea00066e2b40 R10: ffffffff9407e460 R11: ffff88019b8adfff R12: 0000000000000000 R13: 00000000206c653f R14: 0000000000001000 R15: ffff8801c618fcf0 generic_perform_write+0x166/0x430 mm/filemap.c:3027 __generic_file_write_iter+0x345/0x540 mm/filemap.c:3162 generic_file_write_iter+0x36f/0x650 mm/filemap.c:3190 call_write_iter include/linux/fs.h:1782 [inline] new_sync_write fs/read_write.c:471 [inline] __vfs_write+0x417/0x5c0 fs/read_write.c:484 vfs_write+0x17f/0x4d0 fs/read_write.c:546 SYSC_write fs/read_write.c:593 [inline] SyS_write+0xc2/0x1a0 fs/read_write.c:585 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457569 RSP: 002b:00007f4ecfb9dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569 RDX: 00000000fffffda2 RSI: 0000000020000540 RDI: 0000000000000007 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4ecfb9e6d4 R13: 00000000004c553a R14: 00000000004d8e68 R15: 00000000ffffffff Allocated by task 190: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.1+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+0x104/0x300 mm/slub.c:4288 __kmalloc_reserve.isra.8+0x2f/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+0x645/0xc40 lib/kobject_uevent.c:476 kobject_synth_uevent+0x6ee/0x838 lib/kobject_uevent.c:205 uevent_store+0x21/0x60 drivers/base/core.c:994 dev_attr_store+0x57/0x80 drivers/base/core.c:714 sysfs_kf_write+0x10a/0x160 fs/sysfs/file.c:141 kernfs_fop_write+0x28b/0x440 fs/kernfs/file.c:316 __vfs_write+0xf4/0x5c0 fs/read_write.c:482 vfs_write+0x17f/0x4d0 fs/read_write.c:546 SYSC_write fs/read_write.c:593 [inline] SyS_write+0xc2/0x1a0 fs/read_write.c:585 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 190: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xac/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:550 skb_release_data+0x495/0x610 net/core/skbuff.c:570 skb_release_all+0x46/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] consume_skb+0xc1/0x330 net/core/skbuff.c:701 netlink_broadcast_filtered+0x2b7/0xa30 net/netlink/af_netlink.c:1488 kobject_uevent_env+0x793/0xc40 lib/kobject_uevent.c:492 kobject_synth_uevent+0x6ee/0x838 lib/kobject_uevent.c:205 uevent_store+0x21/0x60 drivers/base/core.c:994 dev_attr_store+0x57/0x80 drivers/base/core.c:714 sysfs_kf_write+0x10a/0x160 fs/sysfs/file.c:141 kernfs_fop_write+0x28b/0x440 fs/kernfs/file.c:316 __vfs_write+0xf4/0x5c0 fs/read_write.c:482 vfs_write+0x17f/0x4d0 fs/read_write.c:546 SYSC_write fs/read_write.c:593 [inline] SyS_write+0xc2/0x1a0 fs/read_write.c:585 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8801cc963900 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 264 bytes inside of 512-byte region [ffff8801cc963900, ffff8801cc963b00) The buggy address belongs to the page: page:ffffea0007325880 count:1 mapcount:0 mapping: (null) index:0xffff8801cc962a00 compound_mapcount: 0 flags: 0x4000000000008100(slab|head) raw: 4000000000008100 0000000000000000 ffff8801cc962a00 00000001000c000b raw: ffffea00075988a0 ffffea00071451a0 ffff8801da802c00 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801cc963900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801cc963980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801cc963a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801cc963a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801cc963b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================