On Sun, Jan 28, 2018 at 11:24:01AM -0800, syzbot wrote: > Hello, > > syzbot hit the following crash on net-next commit > 6bb46bc57c8e9ce947cc605e555b7204b44d2b10 (Fri Jan 26 16:00:23 2018 +0000) > Merge branch 'cxgb4-fix-dump-collection-when-firmware-crashed' > > Unfortunately, I don't have any reproducer for this crash yet. > Raw console output is attached. > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+c8e66da874feb11aa...@syzkaller.appspotmail.com > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > ================================================================== > BUG: KASAN: out-of-bounds in ip6_dst_idev include/net/ip6_fib.h:192 [inline] > BUG: KASAN: out-of-bounds in ip6_xmit+0x1f76/0x2260 > net/ipv6/ip6_output.c:264 > Read of size 8 at addr ffff8801bcc8cc18 by task syz-executor2/11459 > > CPU: 0 PID: 11459 Comm: syz-executor2 Not tainted 4.15.0-rc9+ #212 > 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_load8_noabort+0x14/0x20 mm/kasan/report.c:430 > ip6_dst_idev include/net/ip6_fib.h:192 [inline] > ip6_xmit+0x1f76/0x2260 net/ipv6/ip6_output.c:264 > inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139 > l2tp_xmit_core net/l2tp/l2tp_core.c:1096 [inline] > l2tp_xmit_skb+0x105f/0x1410 net/l2tp/l2tp_core.c:1191 > pppol2tp_sendmsg+0x470/0x670 net/l2tp/l2tp_ppp.c:341 > sock_sendmsg_nosec net/socket.c:630 [inline] > sock_sendmsg+0xca/0x110 net/socket.c:640 > ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046 > __sys_sendmsg+0xe5/0x210 net/socket.c:2080 > SYSC_sendmsg net/socket.c:2091 [inline] > SyS_sendmsg+0x2d/0x50 net/socket.c:2087 > entry_SYSCALL_64_fastpath+0x29/0xa0 > RIP: 0033:0x453299 > RSP: 002b:00007fcfef194c58 EFLAGS: 00000212 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 000000000071bf58 RCX: 0000000000453299 > RDX: 0000000000000081 RSI: 000000002037ffc8 RDI: 0000000000000014 > RBP: 000000000000036f R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f4308 > R13: 00000000ffffffff R14: 00007fcfef1956d4 R15: 000000000000000b > > Allocated by task 11466: > 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+0x12e/0x760 mm/slab.c:3544 > dst_alloc+0x11f/0x1a0 net/core/dst.c:104 > rt_dst_alloc+0xe9/0x520 net/ipv4/route.c:1497 > ip_route_input_slow net/ipv4/route.c:2006 [inline] > ip_route_input_rcu+0x1076/0x3200 net/ipv4/route.c:2137 > ip_route_input_noref+0xf5/0x1e0 net/ipv4/route.c:2083 > ip_rcv_finish+0x3a6/0x2040 net/ipv4/ip_input.c:348 > NF_HOOK include/linux/netfilter.h:288 [inline] > ip_rcv+0xc5a/0x1840 net/ipv4/ip_input.c:493 > __netif_receive_skb_core+0x1a41/0x3460 net/core/dev.c:4547 > __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4612 > netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4686 > netif_receive_skb+0xae/0x390 net/core/dev.c:4710 > tun_rx_batched.isra.53+0x5ee/0x870 drivers/net/tun.c:1558 > tun_get_user+0x25de/0x3940 drivers/net/tun.c:1958 > tun_chr_write_iter+0xb9/0x160 drivers/net/tun.c:1986 > call_write_iter include/linux/fs.h:1772 [inline] > do_iter_readv_writev+0x525/0x7f0 fs/read_write.c:653 > do_iter_write+0x154/0x540 fs/read_write.c:932 > vfs_writev+0x18a/0x340 fs/read_write.c:977 > do_writev+0xfc/0x2a0 fs/read_write.c:1012 > SYSC_writev fs/read_write.c:1085 [inline] > SyS_writev+0x27/0x30 fs/read_write.c:1082 > entry_SYSCALL_64_fastpath+0x29/0xa0 > > Freed by task 7176: > 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 > dst_destroy+0x257/0x370 net/core/dst.c:140 > dst_destroy_rcu+0x16/0x20 net/core/dst.c:153 > __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 ffff8801bcc8cc00 > which belongs to the cache ip_dst_cache of size 168 > The buggy address is located 24 bytes inside of > 168-byte region [ffff8801bcc8cc00, ffff8801bcc8cca8) > The buggy address belongs to the page: > page:ffffea0006f32300 count:1 mapcount:0 mapping:ffff8801bcc8c000 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffff8801bcc8c000 0000000000000000 0000000100000010 > raw: ffffea00074da720 ffffea000743cb20 ffff8801d6fe34c0 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801bcc8cb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff8801bcc8cb80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc > > ffff8801bcc8cc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ^ > ffff8801bcc8cc80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc > ffff8801bcc8cd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This bug is generated by a dumb bot. It may contain errors. > See https://goo.gl/tpsmEJ for details. > Direct all questions to syzkal...@googlegroups.com. > > syzbot will keep track of this bug report. > If you forgot to add the Reported-by tag, once the fix for this bug is > merged > into any tree, please reply to this email with: > #syz fix: exact-commit-title
No reproducer and last occurred 58 days ago (on commit f44b1886a5f876c8). Probably was fixed by commit b954f94023dcc61: #syz fix: l2tp: fix races with ipv4-mapped ipv6 addresses - Eric