On Sun, Dec 17, 2017 at 09:52:01PM -0800, syzbot wrote: > Hello, > > syzkaller hit the following crash on > f3b5ad89de16f5d42e8ad36fbdf85f705c1ae051 > git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > C reproducer is attached > syzkaller reproducer is attached. See https://goo.gl/kgGztJ > for information about syzkaller reproducers > > > ================================================================== > BUG: KASAN: double-free or invalid-free in skb_free_head+0x74/0xb0 > net/core/skbuff.c:550 > > CPU: 0 PID: 3142 Comm: sshd Not tainted 4.15.0-rc3+ #225 > 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_double_free+0x55/0x80 mm/kasan/report.c:333 > kasan_slab_free+0xa3/0xc0 mm/kasan/kasan.c:514 > __cache_free mm/slab.c:3488 [inline] > kfree+0xca/0x250 mm/slab.c:3803 > skb_free_head+0x74/0xb0 net/core/skbuff.c:550 > skb_release_data+0x58c/0x790 net/core/skbuff.c:570 > skb_release_all+0x4a/0x60 net/core/skbuff.c:627 > __kfree_skb net/core/skbuff.c:641 [inline] > consume_skb+0x153/0x490 net/core/skbuff.c:701 > __dev_kfree_skb_any+0x85/0xa0 net/core/dev.c:2515 > dev_consume_skb_any include/linux/netdevice.h:3276 [inline] > free_old_xmit_skbs.isra.28+0x15a/0x2c0 drivers/net/virtio_net.c:1167 > start_xmit+0x1b9/0x1650 drivers/net/virtio_net.c:1314 > __netdev_start_xmit include/linux/netdevice.h:4042 [inline] > netdev_start_xmit include/linux/netdevice.h:4051 [inline] > xmit_one net/core/dev.c:2991 [inline] > dev_hard_start_xmit+0x248/0xac0 net/core/dev.c:3007 > sch_direct_xmit+0x31d/0x6d0 net/sched/sch_generic.c:187 > __dev_xmit_skb net/core/dev.c:3189 [inline] > __dev_queue_xmit+0x16f4/0x2070 net/core/dev.c:3456 > dev_queue_xmit+0x17/0x20 net/core/dev.c:3521 > neigh_hh_output include/net/neighbour.h:472 [inline] > neigh_output include/net/neighbour.h:480 [inline] > ip_finish_output2+0xece/0x1460 net/ipv4/ip_output.c:229 > ip_finish_output+0x85e/0xd10 net/ipv4/ip_output.c:317 > NF_HOOK_COND include/linux/netfilter.h:239 [inline] > ip_output+0x1cc/0x860 net/ipv4/ip_output.c:405 > dst_output include/net/dst.h:460 [inline] > ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124 > ip_queue_xmit+0x8c6/0x18e0 net/ipv4/ip_output.c:504 > tcp_transmit_skb+0x1b12/0x38b0 net/ipv4/tcp_output.c:1176 > tcp_write_xmit+0x680/0x5190 net/ipv4/tcp_output.c:2367 > __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2543 > tcp_push+0x538/0x770 net/ipv4/tcp.c:730 > tcp_sendmsg_locked+0x2663/0x3b30 net/ipv4/tcp.c:1424 > tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1461 > inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 > sock_sendmsg_nosec net/socket.c:636 [inline] > sock_sendmsg+0xca/0x110 net/socket.c:646 > sock_write_iter+0x31a/0x5d0 net/socket.c:915 > call_write_iter include/linux/fs.h:1772 [inline] > new_sync_write fs/read_write.c:469 [inline] > __vfs_write+0x684/0x970 fs/read_write.c:482 > vfs_write+0x189/0x510 fs/read_write.c:544 > SYSC_write fs/read_write.c:589 [inline] > SyS_write+0xef/0x220 fs/read_write.c:581 > entry_SYSCALL_64_fastpath+0x1f/0x96 > RIP: 0033:0x7f7a61d22370 > RSP: 002b:00007ffc93b90b98 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > RAX: ffffffffffffffda RBX: 0000563815b397d0 RCX: 00007f7a61d22370 > RDX: 0000000000000038 RSI: 0000563815b2b460 RDI: 0000000000000003 > RBP: 00007ffc93b90b20 R08: 0000000000000001 R09: 0101010101010101 > R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000040 > R13: 000000000000005e R14: 0000563815b304e0 R15: 00007ffc93b90b70 > > Allocated by task 3142: > 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 > __do_kmalloc_node mm/slab.c:3672 [inline] > __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3686 > __kmalloc_reserve.isra.41+0x41/0xd0 net/core/skbuff.c:137 > __alloc_skb+0x13b/0x780 net/core/skbuff.c:205 > alloc_skb_fclone include/linux/skbuff.h:1025 [inline] > sk_stream_alloc_skb+0x11d/0x900 net/ipv4/tcp.c:870 > tcp_sendmsg_locked+0x1341/0x3b30 net/ipv4/tcp.c:1299 > tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1461 > inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 > sock_sendmsg_nosec net/socket.c:636 [inline] > sock_sendmsg+0xca/0x110 net/socket.c:646 > sock_write_iter+0x31a/0x5d0 net/socket.c:915 > call_write_iter include/linux/fs.h:1772 [inline] > new_sync_write fs/read_write.c:469 [inline] > __vfs_write+0x684/0x970 fs/read_write.c:482 > vfs_write+0x189/0x510 fs/read_write.c:544 > SYSC_write fs/read_write.c:589 [inline] > SyS_write+0xef/0x220 fs/read_write.c:581 > entry_SYSCALL_64_fastpath+0x1f/0x96 > > Freed by task 3142: > 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] > kfree+0xca/0x250 mm/slab.c:3803 > skb_free_head+0x74/0xb0 net/core/skbuff.c:550 > skb_release_data+0x58c/0x790 net/core/skbuff.c:570 > skb_release_all+0x4a/0x60 net/core/skbuff.c:627 > __kfree_skb net/core/skbuff.c:641 [inline] > consume_skb+0x153/0x490 net/core/skbuff.c:701 > __dev_kfree_skb_any+0x85/0xa0 net/core/dev.c:2515 > dev_consume_skb_any include/linux/netdevice.h:3276 [inline] > free_old_xmit_skbs.isra.28+0x15a/0x2c0 drivers/net/virtio_net.c:1167 > start_xmit+0x1b9/0x1650 drivers/net/virtio_net.c:1314 > __netdev_start_xmit include/linux/netdevice.h:4042 [inline] > netdev_start_xmit include/linux/netdevice.h:4051 [inline] > xmit_one net/core/dev.c:2991 [inline] > dev_hard_start_xmit+0x248/0xac0 net/core/dev.c:3007 > sch_direct_xmit+0x31d/0x6d0 net/sched/sch_generic.c:187 > __dev_xmit_skb net/core/dev.c:3189 [inline] > __dev_queue_xmit+0x16f4/0x2070 net/core/dev.c:3456 > dev_queue_xmit+0x17/0x20 net/core/dev.c:3521 > neigh_hh_output include/net/neighbour.h:472 [inline] > neigh_output include/net/neighbour.h:480 [inline] > ip_finish_output2+0xece/0x1460 net/ipv4/ip_output.c:229 > ip_finish_output+0x85e/0xd10 net/ipv4/ip_output.c:317 > NF_HOOK_COND include/linux/netfilter.h:239 [inline] > ip_output+0x1cc/0x860 net/ipv4/ip_output.c:405 > dst_output include/net/dst.h:460 [inline] > ip_local_out+0x95/0x160 net/ipv4/ip_output.c:124 > ip_queue_xmit+0x8c6/0x18e0 net/ipv4/ip_output.c:504 > tcp_transmit_skb+0x1b12/0x38b0 net/ipv4/tcp_output.c:1176 > tcp_write_xmit+0x680/0x5190 net/ipv4/tcp_output.c:2367 > __tcp_push_pending_frames+0xa0/0x250 net/ipv4/tcp_output.c:2543 > tcp_push+0x538/0x770 net/ipv4/tcp.c:730 > tcp_sendmsg_locked+0x2663/0x3b30 net/ipv4/tcp.c:1424 > tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1461 > inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763 > sock_sendmsg_nosec net/socket.c:636 [inline] > sock_sendmsg+0xca/0x110 net/socket.c:646 > sock_write_iter+0x31a/0x5d0 net/socket.c:915 > call_write_iter include/linux/fs.h:1772 [inline] > new_sync_write fs/read_write.c:469 [inline] > __vfs_write+0x684/0x970 fs/read_write.c:482 > vfs_write+0x189/0x510 fs/read_write.c:544 > SYSC_write fs/read_write.c:589 [inline] > SyS_write+0xef/0x220 fs/read_write.c:581 > entry_SYSCALL_64_fastpath+0x1f/0x96 > > The buggy address belongs to the object at ffff8801c719cdc0 > which belongs to the cache kmalloc-1024 of size 1024 > The buggy address is located 0 bytes inside of > 1024-byte region [ffff8801c719cdc0, ffff8801c719d1c0) > The buggy address belongs to the page: > page:0000000009b6561b count:1 mapcount:0 mapping:00000000749a03ca index:0x0 > compound_mapcount: 0 > flags: 0x2fffc0000008100(slab|head) > raw: 02fffc0000008100 ffff8801c719c040 0000000000000000 0000000100000007 > raw: ffffea00071edf20 ffffea00071c9220 ffff8801db000ac0 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801c719cc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801c719cd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ffff8801c719cd80: fb fb fb fb fb fb fb fb fb fb fb fb 00 00 00 00 > ^ > ffff8801c719ce00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff8801c719ce80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ================================================================== > > > --- > 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. > Please credit me with: Reported-by: syzbot <syzkal...@googlegroups.com> > > syzbot will keep track of this bug report. > Once a fix for this bug is merged into any tree, reply to this email with: > #syz fix: exact-commit-title
This crash is no longer occurring, and the reproducer actually used AF_ALG with "pcrypt", so this was probably the slab corruption fixed by commit d76c68109f37c: #syz fix: crypto: pcrypt - fix freeing pcrypt instances - Eric
