BUG: KASAN: use-after-free in skb_release_data+0x5cf/0x790 net/core/skbuff.c:567 Read of size 1 at addr ffff8801ce0c7d42 by task syz-executor3/3475 CPU: 0 PID: 3475 Comm: syz-executor3 Not tainted 4.13.0-rc5-next-20170815+ #3 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_load1_noabort+0x14/0x20 mm/kasan/report.c:427 skb_release_data+0x5cf/0x790 net/core/skbuff.c:567 skb_release_all+0x4a/0x60 net/core/skbuff.c:631 __kfree_skb net/core/skbuff.c:645 [inline] kfree_skb+0x15d/0x4c0 net/core/skbuff.c:663 ip_frag_queue net/ipv4/ip_fragment.c:474 [inline] ip_defrag+0xc69/0x4000 net/ipv4/ip_fragment.c:680 ip_local_deliver+0x174/0x6d0 net/ipv4/ip_input.c:253 dst_input include/net/dst.h:477 [inline] ip_rcv_finish+0x8db/0x19c0 net/ipv4/ip_input.c:397 NF_HOOK include/linux/netfilter.h:248 [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+0x5e7/0x860 drivers/net/tun.c:1221 tun_get_user+0x11dd/0x2150 drivers/net/tun.c:1542 tun_chr_write_iter+0xd8/0x190 drivers/net/tun.c:1568 call_write_iter include/linux/fs.h:1742 [inline] new_sync_write fs/read_write.c:457 [inline] __vfs_write+0x684/0x970 fs/read_write.c:470 vfs_write+0x189/0x510 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: 0033:0x40b751 RSP: 002b:00007fb3dbcfec10 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 000000000040b751 RDX: 0000000000000036 RSI: 0000000020002000 RDI: 0000000000000003 RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000f4246 R11: 0000000000000293 R12: 00000000004bab1b R13: 00000000ffffffff R14: 0000000000000036 R15: 0000000020002000 The buggy address belongs to the page: page:ffffea00073831c0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x200000000000000() raw: 0200000000000000 0000000000000000 0000000000000000 00000000ffffffff raw: 0000000000000000 0000000100000001 0000000000000000 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801ce0c7c00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8801ce0c7c80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8801ce0c7d00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8801ce0c7d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8801ce0c7e00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================