__dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold+0x10a/0x154 lib/fault-inject.c:149 ================================================================== should_failslab+0xd6/0x130 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc mm/slab.c:3376 [inline] __do_kmalloc mm/slab.c:3718 [inline] __kmalloc+0x2c1/0x400 mm/slab.c:3729 BUG: KASAN: use-after-free in p9_client_clunk+0x1fc/0x240 net/9p/client.c:1505 Read of size 8 at addr ffff88809aa74b00 by task syz-executor.1/13923 kmalloc include/linux/slab.h:493 [inline] SYSC_memfd_create mm/shmem.c:3738 [inline] SyS_memfd_create+0xbc/0x3c0 mm/shmem.c:3708 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45deb9 RSP: 002b:00007f349e053a28 EFLAGS: 00000246 ORIG_RAX: 000000000000013f RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 000000000045deb9 RDX: 0000000020000218 RSI: 0000000000000000 RDI: 00000000004c2927 RBP: 0000000000020000 R08: 0000000020000218 R09: 0000000000000000 R10: fe03f80fe03f80ff R11: 0000000000000246 R12: 0000000000000001 R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020000080 CPU: 1 PID: 13923 Comm: syz-executor.1 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 nla_parse: 7 callbacks suppressed netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. 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:00007f778c0acc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000021800 RCX: 000000000045deb9 RDX: 0000000020000000 RSI: 0000000020000040 RDI: 0000000000000000 RBP: 00007f778c0acca0 R08: 0000000020000140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000027 R13: 00007ffe0bb6416f R14: 00007f778c0ad9c0 R15: 000000000118bf2c Allocated by task 13923: 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 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] p9_fid_create+0x47/0x3a0 net/9p/client.c:918 p9_client_attach+0x6d/0x750 net/9p/client.c:1158 v9fs_session_init+0xc03/0x1540 fs/9p/v9fs.c:471 v9fs_mount+0x73/0x860 fs/9p/vfs_super.c:135 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 Freed by task 13923: 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 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 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 sget_userns+0x9c4/0xc10 fs/super.c:537 sget+0xd1/0x110 fs/super.c:572 v9fs_mount+0x9e/0x860 fs/9p/vfs_super.c:141 mount_fs+0x92/0x2a0 fs/super.c:1237 CPU: 0 PID: 13984 Comm: syz-executor.0 Not tainted 4.14.206-syzkaller #0 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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 Call Trace: do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 entry_SYSCALL_64_after_hwframe+0x46/0xbb fail_dump lib/fault-inject.c:51 [inline] should_fail.cold+0x10a/0x154 lib/fault-inject.c:149 should_failslab+0xd6/0x130 mm/failslab.c:32 The buggy address belongs to the object at ffff88809aa74b00 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 0 bytes inside of 96-byte region [ffff88809aa74b00, ffff88809aa74b60) slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc_node mm/slab.c:3297 [inline] kmem_cache_alloc_node+0x263/0x410 mm/slab.c:3640 The buggy address belongs to the page: __alloc_skb+0x5c/0x510 net/core/skbuff.c:193 page:ffffea00026a9d00 count:1 mapcount:0 mapping:ffff88809aa74000 index:0x0 alloc_skb include/linux/skbuff.h:980 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1159 [inline] netlink_sendmsg+0x901/0xb80 net/netlink/af_netlink.c:1853 flags: 0xfff00000000100(slab) raw: 00fff00000000100 ffff88809aa74000 0000000000000000 0000000100000020 raw: ffffea00027b17e0 ffffea000278f920 ffff88813fe824c0 0000000000000000 page dumped because: kasan: bad access detected sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 Memory state around the buggy address: ffff88809aa74a00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062 ffff88809aa74a80: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc >ffff88809aa74b00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff88809aa74b80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88809aa74c00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================