RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2f5604a6d4
R13: 00000000004c12ef R14: 00000000004d2108 R15: 0000000000000007
==================================================================
BUG: KASAN: use-after-free in tun_chr_read_iter+0x1bf/0x1e0 drivers/net/tun.c:2222
Read of size 8 at addr ffff8801650a4650 by task syz-executor2/3533

CPU: 1 PID: 3533 Comm: syz-executor2 Not tainted 4.19.0+ #309
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 tun_chr_read_iter+0x1bf/0x1e0 drivers/net/tun.c:2222
 call_read_iter include/linux/fs.h:1821 [inline]
 new_sync_read fs/read_write.c:406 [inline]
 __vfs_read+0x6ac/0x9b0 fs/read_write.c:418
 vfs_read+0x17f/0x3c0 fs/read_write.c:452
 ksys_pread64+0x181/0x1b0 fs/read_write.c:626
 __do_sys_pread64 fs/read_write.c:636 [inline]
 __se_sys_pread64 fs/read_write.c:633 [inline]
 __x64_sys_pread64+0x97/0xf0 fs/read_write.c:633
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2f56028c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457569
RDX: 0000000000000027 RSI: 0000000020000340 RDI: 0000000000000006
RBP: 000000000072bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2f560296d4
R13: 00000000004c32d7 R14: 00000000004d4ef8 R15: 00000000ffffffff

Allocated by task 3527:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 __do_kmalloc_node mm/slab.c:3684 [inline]
 __kmalloc_node+0x50/0x70 mm/slab.c:3691
 kmalloc_node include/linux/slab.h:589 [inline]
 kvmalloc_node+0xb9/0xf0 mm/util.c:416
 kvmalloc include/linux/mm.h:577 [inline]
 kvzalloc include/linux/mm.h:585 [inline]
 alloc_netdev_mqs+0x17b/0xfe0 net/core/dev.c:8937
 tun_set_iff drivers/net/tun.c:2725 [inline]
 __tun_chr_ioctl+0x2030/0x46e0 drivers/net/tun.c:3018
 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3282
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 3527:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xcf/0x230 mm/slab.c:3817
 kvfree+0x61/0x70 mm/util.c:445
 netdev_freemem net/core/dev.c:8891 [inline]
 free_netdev+0x393/0x450 net/core/dev.c:9040
 tun_set_iff drivers/net/tun.c:2813 [inline]
 __tun_chr_ioctl+0x2b54/0x46e0 drivers/net/tun.c:3018
 tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:3282
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801650a3380
 which belongs to the cache kmalloc-16k of size 16384
The buggy address is located 4816 bytes inside of
 16384-byte region [ffff8801650a3380, ffff8801650a7380)
The buggy address belongs to the page:
page:ffffea0005942800 count:1 mapcount:0 mapping:ffff8801da802200 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea000590b008 ffffea0005e15e08 ffff8801da802200
raw: 0000000000000000 ffff8801650a3380 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801650a4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801650a4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801650a4600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff8801650a4680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801650a4700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================