SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3072 ================================================================== do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 BUG: KASAN: use-after-free in p9_client_clunk+0x1fc/0x240 net/9p/client.c:1505 entry_SYSCALL_64_after_hwframe+0x46/0xbb Read of size 8 at addr ffff8880a5102200 by task syz-executor.0/14826 RIP: 0033:0x45deb9 RSP: 002b:00007fd16ca82c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000021800 RCX: 000000000045deb9 RDX: 0000000020000100 RSI: 0000000020000040 RDI: 0000000000000000 RBP: 00007fd16ca82ca0 R08: 0000000020000080 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007ffd3f17dcff R14: 00007fd16ca839c0 R15: 000000000118bf2c CPU: 1 PID: 14826 Comm: syz-executor.0 Not tainted 4.14.206-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351 kasan_report mm/kasan/report.c:409 [inline] __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430 p9_client_clunk+0x1fc/0x240 net/9p/client.c:1505 v9fs_mount+0x69f/0x860 fs/9p/vfs_super.c:200 mount_fs+0x92/0x2a0 fs/super.c:1237 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0xe53/0x2a00 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3072 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45deb9 RSP: 002b:00007f005de9cc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000021800 RCX: 000000000045deb9 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 RDX: 0000000020000100 RSI: 0000000020000040 RDI: 0000000000000000 RBP: 00007f005de9cca0 R08: 0000000020000200 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000025 R13: 00007ffe44611dcf R14: 00007f005de9d9c0 R15: 000000000118bf2c Allocated by task 14826: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551 CPU: 0 PID: 14863 Comm: syz-executor.2 Not tainted 4.14.206-syzkaller #0 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 kmalloc include/linux/slab.h:488 [inline] p9_fid_create+0x47/0x3a0 net/9p/client.c:918 Call Trace: p9_client_attach+0x6d/0x750 net/9p/client.c:1158 __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 v9fs_session_init+0xc03/0x1540 fs/9p/v9fs.c:471 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold+0x10a/0x154 lib/fault-inject.c:149 v9fs_mount+0x73/0x860 fs/9p/vfs_super.c:135 should_failslab+0xd6/0x130 mm/failslab.c:32 mount_fs+0x92/0x2a0 fs/super.c:1237 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc mm/slab.c:3376 [inline] kmem_cache_alloc+0x28e/0x3c0 mm/slab.c:3550 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046 kmem_cache_zalloc include/linux/slab.h:651 [inline] alloc_vfsmnt+0x23/0x7f0 fs/namespace.c:205 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0xe53/0x2a00 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3072 vfs_kern_mount.part.0+0x27/0x470 fs/namespace.c:1039 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0xe53/0x2a00 fs/namespace.c:2879 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 14826: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xc9/0x250 mm/slab.c:3815 p9_client_destroy.cold+0x67/0xaa net/9p/client.c:1121 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3072 v9fs_session_close+0x45/0x2c0 fs/9p/v9fs.c:511 v9fs_kill_super+0x49/0x90 fs/9p/vfs_super.c:233 deactivate_locked_super+0x6c/0xd0 fs/super.c:319 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 sget_userns+0x9c4/0xc10 fs/super.c:537 entry_SYSCALL_64_after_hwframe+0x46/0xbb sget+0xd1/0x110 fs/super.c:572 RIP: 0033:0x45deb9 v9fs_mount+0x9e/0x860 fs/9p/vfs_super.c:141 RSP: 002b:00007fd16ca82c78 EFLAGS: 00000246 mount_fs+0x92/0x2a0 fs/super.c:1237 ORIG_RAX: 00000000000000a5 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046 RAX: ffffffffffffffda RBX: 0000000000021800 RCX: 000000000045deb9 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0xe53/0x2a00 fs/namespace.c:2879 RDX: 0000000020000100 RSI: 0000000020000040 RDI: 0000000000000000 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3072 RBP: 00007fd16ca82ca0 R08: 0000000020000080 R09: 0000000000000000 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004 entry_SYSCALL_64_after_hwframe+0x46/0xbb R13: 00007ffd3f17dcff R14: 00007fd16ca839c0 R15: 000000000118bf2c The buggy address belongs to the object at ffff8880a5102200 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 0 bytes inside of 96-byte region [ffff8880a5102200, ffff8880a5102260) The buggy address belongs to the page: page:ffffea0002944080 count:1 mapcount:0 mapping:ffff8880a5102000 index:0xffff8880a5102100 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffff8880a5102000 ffff8880a5102100 000000010000001c raw: ffffea0002ad12e0 ffffea00028dcfe0 ffff88813fe824c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: FAULT_INJECTION: forcing a failure. name fail_page_alloc, interval 1, probability 0, space 0, times 0 ffff8880a5102100: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880a5102180: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff8880a5102200: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff8880a5102280: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff8880a5102300: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ================================================================== 9pnet: Insufficient options for proto=fd CPU: 0 PID: 14871 Comm: syz-executor.2 Tainted: G B 4.14.206-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011