RDX: 000000000000fff6 RSI: 0000000020011fd2 RDI: 0000000000000016 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004c2d5c R14: 00000000004d4da0 R15: 0000000000000000 ================================================================== BUG: KASAN: use-after-free in memcpy include/linux/string.h:345 [inline] BUG: KASAN: use-after-free in iov_iter_copy_from_user_atomic+0xb8d/0xfa0 lib/iov_iter.c:916 Read of size 21 at addr ffff8801b55bb8a0 by task kworker/1:2/2137 CPU: 1 PID: 2137 Comm: kworker/1:2 Not tainted 4.18.0-rc5-next-20180720+ #12 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events p9_write_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 memcpy+0x23/0x50 mm/kasan/kasan.c:302 memcpy include/linux/string.h:345 [inline] iov_iter_copy_from_user_atomic+0xb8d/0xfa0 lib/iov_iter.c:916 generic_perform_write+0x469/0x6c0 mm/filemap.c:3058 __generic_file_write_iter+0x26e/0x630 mm/filemap.c:3175 ext4_file_write_iter+0x390/0x1450 fs/ext4/file.c:266 call_write_iter include/linux/fs.h:1826 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x6af/0x9d0 fs/read_write.c:487 vfs_write+0x1fc/0x560 fs/read_write.c:549 kernel_write+0xab/0x120 fs/read_write.c:526 p9_fd_write net/9p/trans_fd.c:427 [inline] p9_write_work+0x6f1/0xd50 net/9p/trans_fd.c:476 process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415 Allocated by task 27977: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 __do_kmalloc mm/slab.c:3718 [inline] __kmalloc+0x14e/0x760 mm/slab.c:3727 kmalloc include/linux/slab.h:518 [inline] p9_fcall_alloc+0x1e/0x90 net/9p/client.c:237 p9_tag_alloc net/9p/client.c:266 [inline] p9_client_prepare_req.part.8+0x107/0xa00 net/9p/client.c:640 p9_client_prepare_req net/9p/client.c:675 [inline] p9_client_rpc+0x242/0x1330 net/9p/client.c:675 p9_client_version net/9p/client.c:890 [inline] p9_client_create+0xca4/0x1537 net/9p/client.c:974 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 legacy_get_tree+0x131/0x460 fs/fs_context.c:674 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743 do_new_mount fs/namespace.c:2603 [inline] do_mount+0x6f2/0x1e20 fs/namespace.c:2927 ksys_mount+0x12d/0x140 fs/namespace.c:3143 __do_sys_mount fs/namespace.c:3157 [inline] __se_sys_mount fs/namespace.c:3154 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3154 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 27977: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 p9_free_req+0xb5/0x120 net/9p/client.c:338 p9_client_rpc+0xa8e/0x1330 net/9p/client.c:739 p9_client_version net/9p/client.c:890 [inline] p9_client_create+0xca4/0x1537 net/9p/client.c:974 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 legacy_get_tree+0x131/0x460 fs/fs_context.c:674 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743 do_new_mount fs/namespace.c:2603 [inline] do_mount+0x6f2/0x1e20 fs/namespace.c:2927 ksys_mount+0x12d/0x140 fs/namespace.c:3143 __do_sys_mount fs/namespace.c:3157 [inline] __se_sys_mount fs/namespace.c:3154 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3154 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 ffff8801b55bb880 which belongs to the cache kmalloc-16384 of size 16384 The buggy address is located 32 bytes inside of 16384-byte region [ffff8801b55bb880, ffff8801b55bf880) The buggy address belongs to the page: page:ffffea0006d56e00 count:1 mapcount:0 mapping:ffff8801da802200 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000010200(slab|head) raw: 02fffc0000010200 ffffea0006fe8e08 ffffea0006505a08 ffff8801da802200 raw: 0000000000000000 ffff8801b55bb880 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b55bb780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801b55bb800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801b55bb880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b55bb900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b55bb980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================