================================================================== BUG: KASAN: stack-out-of-bounds in iov_iter_advance+0x4b3/0x4f0 lib/iov_iter.c:491 Read of size 8 at addr ffff8800a08ff6f8 by task syz-executor.2/5469 CPU: 0 PID: 5469 Comm: syz-executor.2 Not tainted 4.4.174+ #17 0000000000000000 04c8eed45b758d7d ffff8800a08ff3a8 ffffffff81aad1a1 0000000000000000 ffffea0002823fc0 ffff8800a08ff6f8 0000000000000008 ffff8800a08ff6f0 ffff8800a08ff3e0 ffffffff81490120 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_address_description+0x6f/0x21b mm/kasan/report.c:252 [] kasan_report_error mm/kasan/report.c:351 [inline] [] kasan_report mm/kasan/report.c:408 [inline] [] kasan_report.cold+0x8c/0x2be mm/kasan/report.c:393 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429 [] iov_iter_advance+0x4b3/0x4f0 lib/iov_iter.c:491 [] tun_get_user+0x2c6/0x2640 drivers/net/tun.c:1124 [] tun_chr_write_iter+0xda/0x190 drivers/net/tun.c:1283 [] new_sync_write fs/read_write.c:480 [inline] [] __vfs_write+0x2e8/0x3d0 fs/read_write.c:493 [] __kernel_write+0x112/0x370 fs/read_write.c:513 [] write_pipe_buf+0x15d/0x1f0 fs/splice.c:1074 [] splice_from_pipe_feed fs/splice.c:776 [inline] [] __splice_from_pipe+0x37e/0x7a0 fs/splice.c:901 [] splice_from_pipe+0x108/0x170 fs/splice.c:936 [] default_file_splice_write+0x3c/0x80 fs/splice.c:1086 [] do_splice_from fs/splice.c:1128 [inline] [] direct_splice_actor+0x126/0x1a0 fs/splice.c:1294 [] splice_direct_to_actor+0x2ce/0x850 fs/splice.c:1247 [] do_splice_direct+0x1a5/0x260 fs/splice.c:1337 [] do_sendfile+0x4ed/0xba0 fs/read_write.c:1229 [] C_SYSC_sendfile fs/read_write.c:1311 [inline] [] compat_SyS_sendfile+0x144/0x160 fs/read_write.c:1294 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a The buggy address belongs to the page: page:ffffea0002823fc0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x0() page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8800a08ff580: 00 00 00 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 f3 ffff8800a08ff600: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8800a08ff680: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 f2 f2 ^ ffff8800a08ff700: 00 00 00 00 00 f2 f2 f2 f2 f2 00 00 00 00 00 f3 ffff8800a08ff780: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================