================================================================== BUG: KASAN: use-after-free in enqueue_timer include/linux/list.h:673 [inline] BUG: KASAN: use-after-free in __mod_timer kernel/time/timer.c:1021 [inline] BUG: KASAN: use-after-free in mod_timer+0x11d3/0x15b0 kernel/time/timer.c:1071 Write of size 8 at addr ffff88004a09b888 by task syz-executor4/6497 CPU: 3 PID: 6497 Comm: syz-executor4 Not tainted 4.13.0-rc7-next-20170901+ #13 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 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 enqueue_timer include/linux/list.h:673 [inline] __mod_timer kernel/time/timer.c:1021 [inline] mod_timer+0x11d3/0x15b0 kernel/time/timer.c:1071 sk_reset_timer+0x22/0x50 net/core/sock.c:2664 inet_csk_reset_xmit_timer include/net/inet_connection_sock.h:243 [inline] tcp_v4_err+0x16f7/0x17e0 net/ipv4/tcp_ipv4.c:492 icmp_socket_deliver+0x21a/0x440 net/ipv4/icmp.c:771 icmp_unreach+0x3d0/0xc50 net/ipv4/icmp.c:879 icmp_rcv+0x6b6/0x1250 net/ipv4/icmp.c:1060 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 process_backlog+0x203/0x740 net/core/dev.c:5132 napi_poll net/core/dev.c:5530 [inline] net_rx_action+0x792/0x1910 net/core/dev.c:5596 __do_softirq+0x2bb/0xbd0 kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 [inline] irq_exit+0x1d3/0x210 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:638 [inline] smp_apic_timer_interrupt+0x177/0x710 arch/x86/kernel/apic/apic.c:1048 apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:577 RIP: 0033:0x406a30 RSP: 002b:0000000000a5f8a0 EFLAGS: 00000a83 ORIG_RAX: ffffffffffffff10 RAX: 000000008433c581 RBX: 0000000000708000 RCX: 000000000000059d RDX: 000000008171d48d RSI: 000000001a8165a0 RDI: 000000009cc517fa RBP: 00000000000000d3 R08: 0000000000000328 R09: 0000005a0000002b R10: 0000000000a5f960 R11: 0000000000000206 R12: 0000000000002b85 R13: 0000000000004a16 R14: 0000000000000000 R15: 00000000f93b22ad Allocated by task 6225: 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:8010 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 6225: 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:7962 [inline] free_netdev+0x2cf/0x360 net/core/dev.c:8124 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 ffff88004a098480 which belongs to the cache kmalloc-16384 of size 16384 The buggy address is located 13320 bytes inside of 16384-byte region [ffff88004a098480, ffff88004a09c480) The buggy address belongs to the page: page:ffffea0001282600 count:1 mapcount:0 mapping:ffff88004a098480 index:0x0 compound_mapcount: 0 flags: 0x500000000008100(slab|head) raw: 0500000000008100 ffff88004a098480 0000000000000000 0000000100000001 raw: ffffea0001285220 ffffea000130b420 ffff88003e802200 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88004a09b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88004a09b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88004a09b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88004a09b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88004a09b980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================