================================================================== BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:673 [inline] BUG: KASAN: use-after-free in enqueue_timer kernel/time/timer.c:520 [inline] BUG: KASAN: use-after-free in __mod_timer kernel/time/timer.c:1021 [inline] BUG: KASAN: use-after-free in mod_timer_pending+0x11d5/0x14e0 kernel/time/timer.c:1045 Write of size 8 at addr ffff8801d3254148 by task syz-executor6/6639 CPU: 0 PID: 6639 Comm: syz-executor6 Not tainted 4.13.0-next-20170904+ #14 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x24e/0x340 mm/kasan/report.c:409 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435 hlist_add_head include/linux/list.h:673 [inline] enqueue_timer kernel/time/timer.c:520 [inline] __mod_timer kernel/time/timer.c:1021 [inline] mod_timer_pending+0x11d5/0x14e0 kernel/time/timer.c:1045 tcp_check_req+0x11a5/0x1630 net/ipv4/tcp_minisocks.c:620 tcp_v4_rcv+0x1f57/0x2f20 net/ipv4/tcp_ipv4.c:1674 ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216 NF_HOOK include/linux/netfilter.h:249 [inline] ip_local_deliver+0x1ce/0x6e0 net/ipv4/ip_input.c:257 dst_input include/net/dst.h:478 [inline] ip_rcv_finish+0x8db/0x19c0 net/ipv4/ip_input.c:397 NF_HOOK include/linux/netfilter.h:249 [inline] ip_rcv+0xc3f/0x17d0 net/ipv4/ip_input.c:488 __netif_receive_skb_core+0x19af/0x33d0 net/core/dev.c:4418 __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4456 netif_receive_skb_internal+0x10b/0x5e0 net/core/dev.c:4527 netif_receive_skb+0xae/0x390 net/core/dev.c:4551 tun_rx_batched.isra.43+0x5ed/0x860 drivers/net/tun.c:1218 tun_get_user+0x11dd/0x2150 drivers/net/tun.c:1539 tun_chr_write_iter+0xde/0x190 drivers/net/tun.c:1565 call_write_iter include/linux/fs.h:1744 [inline] new_sync_write fs/read_write.c:457 [inline] __vfs_write+0x68a/0x970 fs/read_write.c:470 vfs_write+0x18f/0x510 fs/read_write.c:518 SYSC_write fs/read_write.c:565 [inline] SyS_write+0xef/0x220 fs/read_write.c:557 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x40c2c1 RSP: 002b:00007f888d6dcc10 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000007180b0 RCX: 000000000040c2c1 RDX: 000000000000003e RSI: 0000000020002000 RDI: 0000000000000015 RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000f4240 R11: 0000000000000293 R12: 00000000004bd980 R13: 00000000ffffffff R14: ffffffffffffffff R15: 0000000000000084 Allocated by task 6293: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 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:3689 [inline] __kmalloc_node+0x47/0x70 mm/slab.c:3696 kmalloc_node include/linux/slab.h:535 [inline] kvmalloc_node+0x64/0xd0 mm/util.c:397 kvmalloc include/linux/mm.h:529 [inline] kvzalloc include/linux/mm.h:537 [inline] alloc_netdev_mqs+0x16e/0xed0 net/core/dev.c:8011 tun_set_iff drivers/net/tun.c:2008 [inline] __tun_chr_ioctl+0x12be/0x3d20 drivers/net/tun.c:2262 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2507 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 entry_SYSCALL_64_fastpath+0x1f/0xbe Freed by task 6293: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 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:3503 [inline] kfree+0xca/0x250 mm/slab.c:3820 kvfree+0x36/0x60 mm/util.c:416 netdev_freemem net/core/dev.c:7963 [inline] free_netdev+0x2cf/0x360 net/core/dev.c:8125 tun_set_iff drivers/net/tun.c:2091 [inline] __tun_chr_ioctl+0x2cf6/0x3d20 drivers/net/tun.c:2262 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2507 vfs_ioctl fs/ioctl.c:45 [inline] do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691 entry_SYSCALL_64_fastpath+0x1f/0xbe The buggy address belongs to the object at ffff8801d3250d40 which belongs to the cache kmalloc-16384 of size 16384 The buggy address is located 13320 bytes inside of 16384-byte region [ffff8801d3250d40, ffff8801d3254d40) The buggy address belongs to the page: page:ffffea00074c9400 count:1 mapcount:0 mapping:ffff8801d3250d40 index:0x0 compound_mapcount: 0 flags: 0x200000000008100(slab|head) raw: 0200000000008100 ffff8801d3250d40 0000000000000000 0000000100000001 raw: ffffea0007044c20 ffffea0007358c20 ffff8801dac02200 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d3254000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d3254080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801d3254100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d3254180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d3254200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================