================================================================== BUG: KASAN: use-after-free in p9_conn_cancel+0x9de/0xd30 net/9p/trans_fd.c:207 Read of size 4 at addr ffff8801b075c2e8 by task kworker/1:2/4574 CPU: 1 PID: 4574 Comm: kworker/1:2 Not tainted 4.18.0-rc4+ #41 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events p9_poll_workfn 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+0x242/0x2fe mm/kasan/report.c:412 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 p9_conn_cancel+0x9de/0xd30 net/9p/trans_fd.c:207 p9_poll_mux net/9p/trans_fd.c:620 [inline] p9_poll_workfn+0x4b2/0x6d0 net/9p/trans_fd.c:1107 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:412 Allocated by task 4689: 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 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 kmalloc include/linux/slab.h:513 [inline] kzalloc include/linux/slab.h:707 [inline] p9_fd_open net/9p/trans_fd.c:796 [inline] p9_fd_create+0x1a7/0x3f0 net/9p/trans_fd.c:1036 p9_client_create+0x915/0x16c9 net/9p/client.c:1062 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 mount_fs+0xae/0x328 fs/super.c:1277 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x581/0x30e0 fs/namespace.c:2848 __do_compat_sys_mount fs/compat.c:125 [inline] __se_compat_sys_mount fs/compat.c:92 [inline] __ia32_compat_sys_mount+0x5d5/0x860 fs/compat.c:92 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 Freed by task 4689: 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_fd_close+0x416/0x5b0 net/9p/trans_fd.c:893 p9_client_create+0xac2/0x16c9 net/9p/client.c:1076 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 mount_fs+0xae/0x328 fs/super.c:1277 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x581/0x30e0 fs/namespace.c:2848 __do_compat_sys_mount fs/compat.c:125 [inline] __se_compat_sys_mount fs/compat.c:92 [inline] __ia32_compat_sys_mount+0x5d5/0x860 fs/compat.c:92 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 The buggy address belongs to the object at ffff8801b075c2c0 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 40 bytes inside of 512-byte region [ffff8801b075c2c0, ffff8801b075c4c0) The buggy address belongs to the page: page:ffffea0006c1d700 count:1 mapcount:0 mapping:ffff8801da800940 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0006cc1c88 ffffea0006c48288 ffff8801da800940 raw: 0000000000000000 ffff8801b075c040 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801b075c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b075c200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8801b075c280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8801b075c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b075c380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================