================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x91/0x2e0 lib/refcount.c:120 Read of size 4 at addr ffff8880a3966d80 by task syz-executor3/21616 CPU: 0 PID: 21616 Comm: syz-executor3 Not tainted 4.20.0+ #9 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x123/0x190 mm/kasan/generic.c:191 kasan_check_read+0x11/0x20 mm/kasan/common.c:100 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] refcount_inc_not_zero_checked+0x91/0x2e0 lib/refcount.c:120 refcount_inc_checked+0x17/0x70 lib/refcount.c:153 sock_hold include/net/sock.h:647 [inline] nr_release+0x62/0x3c0 net/netrom/af_netrom.c:523 __sock_release+0xd3/0x250 net/socket.c:579 sock_close+0x1b/0x30 net/socket.c:1141 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x19d6/0x2650 kernel/exit.c:867 do_group_exit+0x177/0x430 kernel/exit.c:970 get_signal+0x8b4/0x19b0 kernel/signal.c:2517 do_signal+0x91/0x1e80 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2f7/0x3b0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f6deedcbcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000073c048 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000073c048 RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000073c04c R13: 00007ffdc329f12f R14: 00007f6deedcc9c0 R15: 000000000073c04c Allocated by task 7823: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc mm/kasan/common.c:482 [inline] kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455 __do_kmalloc_node mm/slab.c:3671 [inline] __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3685 __kmalloc_reserve.isra.0+0x40/0xe0 net/core/skbuff.c:140 __alloc_skb+0x12d/0x730 net/core/skbuff.c:208 alloc_skb_fclone include/linux/skbuff.h:1053 [inline] sk_stream_alloc_skb+0x147/0x9b0 net/ipv4/tcp.c:874 tcp_sendmsg_locked+0xe6e/0x3e80 net/ipv4/tcp.c:1286 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1443 inet_sendmsg+0x1af/0x740 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 sock_write_iter+0x379/0x5e0 net/socket.c:900 call_write_iter include/linux/fs.h:1862 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x764/0xb40 fs/read_write.c:487 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x105/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7831: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kfree+0xcf/0x230 mm/slab.c:3804 skb_free_head+0x93/0xb0 net/core/skbuff.c:553 skb_release_data+0x6ea/0x970 net/core/skbuff.c:573 skb_release_all+0x4d/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] consume_skb net/core/skbuff.c:701 [inline] consume_skb+0x18c/0x550 net/core/skbuff.c:695 __dev_kfree_skb_any+0xa4/0xd0 net/core/dev.c:2813 dev_consume_skb_any include/linux/netdevice.h:3591 [inline] free_old_xmit_skbs+0xca/0x200 drivers/net/virtio_net.c:1346 start_xmit+0x1b4/0x17c0 drivers/net/virtio_net.c:1517 __netdev_start_xmit include/linux/netdevice.h:4382 [inline] netdev_start_xmit include/linux/netdevice.h:4391 [inline] xmit_one net/core/dev.c:3278 [inline] dev_hard_start_xmit+0x261/0xc70 net/core/dev.c:3294 sch_direct_xmit+0x452/0x1100 net/sched/sch_generic.c:327 qdisc_restart net/sched/sch_generic.c:390 [inline] __qdisc_run+0x606/0x19d0 net/sched/sch_generic.c:398 qdisc_run include/net/pkt_sched.h:121 [inline] qdisc_run include/net/pkt_sched.h:118 [inline] __dev_xmit_skb net/core/dev.c:3473 [inline] __dev_queue_xmit+0x29d0/0x3a60 net/core/dev.c:3832 dev_queue_xmit+0x18/0x20 net/core/dev.c:3897 neigh_hh_output include/net/neighbour.h:498 [inline] neigh_output include/net/neighbour.h:506 [inline] ip_finish_output2+0x11f1/0x1a00 net/ipv4/ip_output.c:229 ip_finish_output+0x7e4/0xf60 net/ipv4/ip_output.c:317 NF_HOOK_COND include/linux/netfilter.h:278 [inline] ip_output+0x226/0x880 net/ipv4/ip_output.c:405 dst_output include/net/dst.h:444 [inline] ip_local_out+0xc4/0x1b0 net/ipv4/ip_output.c:124 __ip_queue_xmit+0x99a/0x1ee0 net/ipv4/ip_output.c:505 ip_queue_xmit+0x5a/0x70 include/net/ip.h:198 __tcp_transmit_skb+0x1add/0x3af0 net/ipv4/tcp_output.c:1160 tcp_transmit_skb net/ipv4/tcp_output.c:1176 [inline] tcp_write_xmit+0x108a/0x5bb0 net/ipv4/tcp_output.c:2401 __tcp_push_pending_frames+0xb4/0x350 net/ipv4/tcp_output.c:2577 tcp_push+0x632/0x8c0 net/ipv4/tcp.c:735 tcp_sendmsg_locked+0x2f79/0x3e80 net/ipv4/tcp.c:1406 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1443 inet_sendmsg+0x1af/0x740 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 sock_write_iter+0x379/0x5e0 net/socket.c:900 call_write_iter include/linux/fs.h:1862 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x764/0xb40 fs/read_write.c:487 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x105/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a3966d00 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff8880a3966d00, ffff8880a3967500) The buggy address belongs to the page: page:ffffea00028e5980 count:1 mapcount:0 mapping:ffff88812c3f0c40 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea00025e6c88 ffffea0002351208 ffff88812c3f0c40 raw: 0000000000000000 ffff8880a3966480 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a3966c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a3966d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a3966d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a3966e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a3966e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================