================================================================== BUG: KASAN: use-after-free in erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698 Read of size 2 at addr ffff8801ccae4c8b by task syz-executor5/29694 CPU: 1 PID: 29694 Comm: syz-executor5 Not tainted 4.15.0-rc9+ #279 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+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/report.c:440 erspan_build_header+0x3bf/0x3d0 net/ipv4/ip_gre.c:698 erspan_xmit+0x3b8/0x13b0 net/ipv4/ip_gre.c:740 __netdev_start_xmit include/linux/netdevice.h:4042 [inline] netdev_start_xmit include/linux/netdevice.h:4051 [inline] packet_direct_xmit+0x315/0x6b0 net/packet/af_packet.c:266 packet_snd net/packet/af_packet.c:2943 [inline] packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2968 sock_sendmsg_nosec net/socket.c:638 [inline] sock_sendmsg+0xca/0x110 net/socket.c:648 SYSC_sendto+0x361/0x5c0 net/socket.c:1729 SyS_sendto+0x40/0x50 net/socket.c:1697 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x452f19 RSP: 002b:00007f4b2125ac58 EFLAGS: 00000212 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f4b2125b700 RCX: 0000000000452f19 RDX: 0000000000000000 RSI: 0000000020011000 RDI: 0000000000000013 RBP: 0000000000000000 R08: 000000002000d000 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000a2f7cf R14: 00007f4b2125b9c0 R15: 0000000000000000 Allocated by task 27977: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc_node+0x144/0x760 mm/slab.c:3634 alloc_task_struct_node kernel/fork.c:156 [inline] dup_task_struct kernel/fork.c:521 [inline] copy_process.part.38+0x198d/0x4b20 kernel/fork.c:1590 copy_process kernel/fork.c:1565 [inline] _do_fork+0x1f7/0xfe0 kernel/fork.c:2044 SYSC_clone kernel/fork.c:2154 [inline] SyS_clone+0x37/0x50 kernel/fork.c:2148 do_syscall_64+0x273/0x920 arch/x86/entry/common.c:285 return_from_SYSCALL_64+0x0/0x75 Freed by task 27992: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3488 [inline] kmem_cache_free+0x83/0x2a0 mm/slab.c:3746 free_task_struct kernel/fork.c:161 [inline] free_task+0x148/0x1a0 kernel/fork.c:389 __put_task_struct+0x248/0x580 kernel/fork.c:426 put_task_struct include/linux/sched/task.h:96 [inline] delayed_put_task_struct+0xca/0x3d0 kernel/exit.c:180 __rcu_reclaim kernel/rcu/rcu.h:195 [inline] rcu_do_batch kernel/rcu/tree.c:2758 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:3012 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2979 [inline] rcu_process_callbacks+0xd6c/0x17f0 kernel/rcu/tree.c:2996 __do_softirq+0x2d7/0xb85 kernel/softirq.c:285 The buggy address belongs to the object at ffff8801ccae4580 which belongs to the cache task_struct of size 6016 The buggy address is located 1803 bytes inside of 6016-byte region [ffff8801ccae4580, ffff8801ccae5d00) The buggy address belongs to the page: page:ffffea000732b900 count:1 mapcount:0 mapping:ffff8801ccae4580 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffff8801ccae4580 0000000000000000 0000000100000001 raw: ffffea0007325620 ffffea00072d2b20 ffff8801dad30200 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801ccae4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801ccae4c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801ccae4c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801ccae4d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801ccae4d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================