ptrace attach of "/root/syz-executor.1 exec"[23567] was attempted by "/root/syz-executor.1 exec"[26661] netlink: 4 bytes leftover after parsing attributes in process `syz-executor.4'. ================================================================== BUG: KASAN: use-after-free in ex_handler_refcount+0x18f/0x1c0 arch/x86/mm/extable.c:49 Write of size 4 at addr ffff888099b65300 by task kworker/1:3/7841 CPU: 1 PID: 7841 Comm: kworker/1:3 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events sco_sock_timeout Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354 kasan_report mm/kasan/report.c:412 [inline] __asan_report_store4_noabort+0x88/0x90 mm/kasan/report.c:437 ex_handler_refcount+0x18f/0x1c0 arch/x86/mm/extable.c:49 fixup_exception+0x8a/0xd0 arch/x86/mm/extable.c:197 do_trap_no_signal arch/x86/kernel/traps.c:209 [inline] do_trap+0x61/0x250 arch/x86/kernel/traps.c:258 do_error_trap+0x15d/0x310 arch/x86/kernel/traps.c:303 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038 RIP: 0010:__noinstr_text_end+0x60f9/0x7813 Code: 8d 80 00 00 00 0f 0b 49 8d 8d e4 00 00 00 0f 0b 49 8d 8d 80 00 00 00 0f 0b 49 8d 8c 24 80 00 00 00 0f 0b 48 8d 8d 80 00 00 00 <0f> 0b 48 8d 8d 80 00 00 00 0f 0b 49 8d 8c 24 80 00 00 00 0f 0b 49 RSP: 0018:ffff8880906e7d28 EFLAGS: 00010287 RAX: ffff88809e36e400 RBX: 0000000000000000 RCX: ffff888099b65300 RDX: 0000000000000000 RSI: ffffffff87462a68 RDI: ffff888098e282c0 RBP: ffff888099b65280 R08: 0000000000000001 R09: ffffed10131c5051 R10: ffff888098e2828b R11: 0000000000074071 R12: ffff888098e28288 R13: ffff8880b4d09200 R14: ffff8880ba12a8c0 R15: ffff8880ba12f000 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Allocated by task 25747: __do_kmalloc_node mm/slab.c:3689 [inline] __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3703 __kmalloc_reserve net/core/skbuff.c:137 [inline] pskb_expand_head+0x159/0xf20 net/core/skbuff.c:1473 skb_realloc_headroom+0xa4/0x110 net/core/skbuff.c:1555 ip6_xmit+0x173e/0x20a0 net/ipv6/ip6_output.c:248 inet6_csk_xmit+0x2fb/0x5c0 net/ipv6/inet6_connection_sock.c:139 l2tp_xmit_core net/l2tp/l2tp_core.c:1041 [inline] l2tp_xmit_skb+0xec6/0x1590 net/l2tp/l2tp_core.c:1139 pppol2tp_sendmsg+0x473/0x660 net/l2tp/l2tp_ppp.c:329 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xc3/0x120 net/socket.c:661 ___sys_sendmsg+0x3b3/0x8e0 net/socket.c:2227 __sys_sendmmsg+0x195/0x470 net/socket.c:2322 __do_sys_sendmmsg net/socket.c:2351 [inline] __se_sys_sendmmsg net/socket.c:2348 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2348 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 25823: __cache_free mm/slab.c:3503 [inline] kfree+0xcc/0x210 mm/slab.c:3822 skb_free_head net/core/skbuff.c:563 [inline] skb_release_data+0x6de/0x920 net/core/skbuff.c:583 skb_release_all net/core/skbuff.c:640 [inline] __kfree_skb net/core/skbuff.c:654 [inline] kfree_skb+0x11a/0x3d0 net/core/skbuff.c:672 neigh_invalidate+0x22c/0x540 net/core/neighbour.c:900 neigh_timer_handler+0x9b2/0xc70 net/core/neighbour.c:986 call_timer_fn+0x177/0x700 kernel/time/timer.c:1338 expire_timers+0x243/0x4e0 kernel/time/timer.c:1375 __run_timers kernel/time/timer.c:1696 [inline] run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1709 __do_softirq+0x265/0x980 kernel/softirq.c:292 The buggy address belongs to the object at ffff888099b65280 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff888099b65280, ffff888099b65a80) The buggy address belongs to the page: page:ffffea000266d900 count:1 mapcount:0 mapping:ffff88813bff0c40 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffffea00027f4888 ffffea00015ec588 ffff88813bff0c40 raw: 0000000000000000 ffff888099b64180 0000000100000003 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888099b65200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888099b65280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888099b65300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888099b65380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888099b65400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================