audit: type=1804 audit(1572376227.055:281): pid=25098 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="invalid_pcr" cause="open_writers" comm="syz-executor.3" name="/root/syzkaller-testdir175722652/syzkaller.XHHI7U/819/bus/file1" dev="sda1" ino=16581 res=1 ================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline] BUG: KASAN: use-after-free in atomic_read arch/x86/include/asm/atomic.h:27 [inline] BUG: KASAN: use-after-free in refcount_inc_not_zero+0xd3/0xe0 lib/refcount.c:120 Read of size 4 at addr ffff8880a1fd1300 by task kworker/u4:3/24758 CPU: 0 PID: 24758 Comm: kworker/u4:3 Not tainted 4.14.151 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: l2tp l2tp_tunnel_del_work Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x138/0x197 lib/dump_stack.c:53 print_address_description.cold+0x7c/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+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429 __read_once_size include/linux/compiler.h:183 [inline] atomic_read arch/x86/include/asm/atomic.h:27 [inline] refcount_inc_not_zero+0xd3/0xe0 lib/refcount.c:120 refcount_inc+0x16/0x40 lib/refcount.c:153 sock_hold include/net/sock.h:619 [inline] pppol2tp_session_sock_hold+0x48/0x60 net/l2tp/l2tp_ppp.c:263 l2tp_tunnel_closeall+0x1ef/0x380 net/l2tp/l2tp_core.c:1332 l2tp_tunnel_del_work+0x64/0x410 net/l2tp/l2tp_core.c:1380 process_one_work+0x863/0x1600 kernel/workqueue.c:2114 worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248 kthread+0x319/0x430 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Allocated by task 6856: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node_track_caller+0x51/0x80 mm/slab.c:3696 __kmalloc_reserve.isra.0+0x40/0xe0 net/core/skbuff.c:137 __alloc_skb+0xcf/0x500 net/core/skbuff.c:205 alloc_skb_fclone include/linux/skbuff.h:1022 [inline] sk_stream_alloc_skb+0xb3/0x780 net/ipv4/tcp.c:855 tcp_sendmsg_locked+0xf62/0x31c0 net/ipv4/tcp.c:1301 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1457 inet_sendmsg+0x122/0x500 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xce/0x110 net/socket.c:656 sock_write_iter+0x21d/0x390 net/socket.c:925 call_write_iter include/linux/fs.h:1777 [inline] new_sync_write fs/read_write.c:469 [inline] __vfs_write+0x4a7/0x6b0 fs/read_write.c:482 vfs_write+0x198/0x500 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xfd/0x230 fs/read_write.c:582 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 6887: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 skb_free_head+0x8b/0xb0 net/core/skbuff.c:554 skb_release_data+0x4af/0x700 net/core/skbuff.c:574 skb_release_all+0x4d/0x60 net/core/skbuff.c:631 __kfree_skb+0x16/0x30 net/core/skbuff.c:645 sk_wmem_free_skb include/net/sock.h:1416 [inline] tcp_clean_rtx_queue net/ipv4/tcp_input.c:3182 [inline] tcp_ack+0x26e0/0x4760 net/ipv4/tcp_input.c:3681 tcp_rcv_established+0xd55/0x1650 net/ipv4/tcp_input.c:5486 tcp_v4_do_rcv+0x563/0x7e0 net/ipv4/tcp_ipv4.c:1467 tcp_v4_rcv+0x241e/0x3170 net/ipv4/tcp_ipv4.c:1741 ip_local_deliver_finish+0x25e/0xad0 net/ipv4/ip_input.c:216 NF_HOOK include/linux/netfilter.h:250 [inline] NF_HOOK include/linux/netfilter.h:244 [inline] ip_local_deliver+0x1c3/0x4a0 net/ipv4/ip_input.c:257 dst_input include/net/dst.h:468 [inline] ip_rcv_finish+0x7be/0x1a50 net/ipv4/ip_input.c:396 NF_HOOK include/linux/netfilter.h:250 [inline] NF_HOOK include/linux/netfilter.h:244 [inline] ip_rcv+0xaa5/0x112b net/ipv4/ip_input.c:493 __netif_receive_skb_core+0x1eae/0x2ca0 net/core/dev.c:4477 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4515 netif_receive_skb_internal+0xe4/0x5a0 net/core/dev.c:4588 napi_skb_finish net/core/dev.c:4949 [inline] napi_gro_receive+0x2f8/0x410 net/core/dev.c:4980 receive_buf+0x532/0x3fc0 drivers/net/virtio_net.c:852 virtnet_receive drivers/net/virtio_net.c:1098 [inline] virtnet_poll+0x515/0xa6e drivers/net/virtio_net.c:1189 napi_poll net/core/dev.c:5598 [inline] net_rx_action+0x490/0xf80 net/core/dev.c:5664 __do_softirq+0x244/0x9a0 kernel/softirq.c:288 The buggy address belongs to the object at ffff8880a1fd1280 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff8880a1fd1280, ffff8880a1fd1a80) The buggy address belongs to the page: page:ffffea000287f400 count:1 mapcount:0 mapping:ffff8880a1fd0180 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000008100(slab|head) raw: 01fffc0000008100 ffff8880a1fd0180 0000000000000000 0000000100000003 raw: ffffea00026e9fa0 ffffea0001b66120 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a1fd1200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a1fd1280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a1fd1300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a1fd1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a1fd1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================