================================================================== BUG: KASAN: use-after-free in perf_output_read_group kernel/events/core.c:5888 [inline] BUG: KASAN: use-after-free in perf_output_read+0xe24/0xf80 kernel/events/core.c:5923 Read of size 8 at addr ffff8880a51a0b48 by task syz-executor.2/9289 CPU: 1 PID: 9289 Comm: syz-executor.2 Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1dc 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+0xa9/0x2b9 mm/kasan/report.c:393 perf_output_read_group kernel/events/core.c:5888 [inline] perf_output_read+0xe24/0xf80 kernel/events/core.c:5923 perf_output_sample+0x1196/0x1720 kernel/events/core.c:5965 __perf_event_output kernel/events/core.c:6278 [inline] perf_event_output_forward+0xf8/0x1f0 kernel/events/core.c:6291 __perf_event_overflow+0x113/0x310 kernel/events/core.c:7536 perf_swevent_overflow+0x17b/0x210 kernel/events/core.c:7612 perf_swevent_event+0x19c/0x270 kernel/events/core.c:7645 do_perf_sw_event kernel/events/core.c:7753 [inline] ___perf_sw_event+0x295/0x480 kernel/events/core.c:7784 __perf_sw_event+0x42/0x80 kernel/events/core.c:7796 perf_sw_event include/linux/perf_event.h:1046 [inline] __do_page_fault+0x6c1/0xb50 arch/x86/mm/fault.c:1483 page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1123 RIP: 0010:copy_user_enhanced_fast_string+0xe/0x20 arch/x86/lib/copy_user_64.S:181 RSP: 0018:ffff88805944fa88 EFLAGS: 00010206 RAX: 0000000000000000 RBX: 0000000000008000 RCX: 0000000000001acb RDX: 0000000000008000 RSI: 0000000020fec000 RDI: ffff88805e6be535 RBP: 0000000020fe5acb R08: ffffed100bcd8000 R09: 0000000000000000 R10: ffffed100bcd7fff R11: ffff88805e6bffff R12: ffff88805e6b8000 R13: 00007ffffffff000 R14: 0000000020fedacb R15: ffff88805e6b8000 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:55 [inline] copyin+0x99/0xc0 lib/iov_iter.c:146 _copy_from_iter_full+0x195/0x680 lib/iov_iter.c:608 copy_from_iter_full include/linux/uio.h:126 [inline] skb_do_copy_data_nocache include/net/sock.h:1886 [inline] skb_copy_to_page_nocache include/net/sock.h:1912 [inline] tcp_sendmsg_locked+0x249d/0x2ef0 net/ipv4/tcp.c:1360 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1457 inet_sendmsg+0x116/0x4d0 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 SYSC_sendto net/socket.c:1763 [inline] SyS_sendto+0x1c7/0x2c0 net/socket.c:1731 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45cb29 RSP: 002b:00007f54c4794c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000502960 RCX: 000000000045cb29 RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000008 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0f0000000000e814 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000a4c R14: 00000000004cd338 R15: 00007f54c47956d4 Allocated by task 8431: 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 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696 __kmalloc_reserve.isra.0+0x35/0xd0 net/core/skbuff.c:137 pskb_expand_head+0x115/0xc90 net/core/skbuff.c:1462 skb_ensure_writable+0x249/0x2e0 net/core/skbuff.c:5091 __bpf_try_make_writable net/core/filter.c:1403 [inline] bpf_try_make_writable net/core/filter.c:1409 [inline] bpf_try_make_head_writable net/core/filter.c:1417 [inline] ____bpf_clone_redirect net/core/filter.c:1781 [inline] bpf_clone_redirect+0x120/0x2c0 net/core/filter.c:1759 0xffffffffa00882d2 Freed by task 8431: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcb/0x260 mm/slab.c:3815 skb_free_head+0x83/0xa0 net/core/skbuff.c:554 pskb_expand_head+0x5cb/0xc90 net/core/skbuff.c:1495 __skb_cow include/linux/skbuff.h:2936 [inline] skb_cow_head include/linux/skbuff.h:2970 [inline] ipgre_xmit+0x405/0x6f0 net/ipv4/ip_gre.c:649 __netdev_start_xmit include/linux/netdevice.h:4039 [inline] netdev_start_xmit include/linux/netdevice.h:4048 [inline] xmit_one net/core/dev.c:3009 [inline] dev_hard_start_xmit+0x186/0x880 net/core/dev.c:3025 __dev_queue_xmit+0x1dce/0x25a0 net/core/dev.c:3525 __bpf_tx_skb net/core/filter.c:1708 [inline] __bpf_redirect_common net/core/filter.c:1747 [inline] __bpf_redirect+0x612/0xa30 net/core/filter.c:1754 ____bpf_clone_redirect net/core/filter.c:1787 [inline] bpf_clone_redirect+0x1e0/0x2c0 net/core/filter.c:1759 0xffffffffa00882d2 The buggy address belongs to the object at ffff8880a51a0a40 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 264 bytes inside of 512-byte region [ffff8880a51a0a40, ffff8880a51a0c40) The buggy address belongs to the page: page:ffffea0002946800 count:1 mapcount:0 mapping:ffff8880a51a0040 index:0xffff8880a51a0a40 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff8880a51a0040 ffff8880a51a0a40 0000000100000005 raw: ffffea00028291e0 ffffea00029cc020 ffff8880aa800940 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a51a0a00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8880a51a0a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a51a0b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a51a0b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a51a0c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ==================================================================