------------[ cut here ]------------ FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 refcount_t: underflow; use-after-free. CPU: 1 PID: 4239 Comm: syzkaller149381 Not tainted 4.16.0-rc2+ #20 WARNING: CPU: 0 PID: 4237 at lib/refcount.c:187 refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:187 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: Kernel panic - not syncing: panic_on_warn set ... __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 fail_dump lib/fault-inject.c:51 [inline] should_fail+0x8c0/0xa40 lib/fault-inject.c:149 should_failslab+0xec/0x120 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:422 [inline] slab_alloc mm/slab.c:3365 [inline] __do_kmalloc mm/slab.c:3703 [inline] __kmalloc+0x63/0x760 mm/slab.c:3714 kmalloc include/linux/slab.h:517 [inline] kzalloc include/linux/slab.h:701 [inline] register_shrinker+0x10e/0x2d0 mm/vmscan.c:268 sget_userns+0xbbf/0xe40 fs/super.c:520 mount_ns+0x6d/0x190 fs/super.c:1029 rpc_mount+0x9e/0xd0 net/sunrpc/rpc_pipe.c:1451 mount_fs+0x66/0x2d0 fs/super.c:1222 vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:2509 [inline] do_new_mount fs/namespace.c:2512 [inline] do_mount+0xea4/0x2bb0 fs/namespace.c:2842 SYSC_mount fs/namespace.c:3058 [inline] SyS_mount+0xab/0x120 fs/namespace.c:3035 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4460f9 RSP: 002b:00007fbcd769ad78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00000000006dcc6c RCX: 00000000004460f9 RDX: 0000000020000080 RSI: 0000000020000040 RDI: 0000000020000000 RBP: 00007fbcd769ad80 R08: 00000000200000c0 R09: 0000000000003131 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc68 R13: ffffffffffffffff R14: 0000000000000037 R15: 0030656c69662f2e CPU: 0 PID: 4237 Comm: syzkaller149381 Not tainted 4.16.0-rc2+ #20 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+0x194/0x24d lib/dump_stack.c:53 panic+0x1e4/0x41c kernel/panic.c:183 __warn+0x1dc/0x200 kernel/panic.c:547 report_bug+0x211/0x2d0 lib/bug.c:184 fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178 fixup_bug arch/x86/kernel/traps.c:247 [inline] do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 invalid_op+0x58/0x80 arch/x86/entry/entry_64.S:957 RIP: 0010:refcount_sub_and_test+0x167/0x1b0 lib/refcount.c:187 RSP: 0018:ffff8801b164f6d8 EFLAGS: 00010286 RAX: dffffc0000000008 RBX: 0000000000000000 RCX: ffffffff815ac30e RDX: 0000000000000000 RSI: 1ffff100362c9e8b RDI: 1ffff100362c9e60 RBP: ffff8801b164f768 R08: 0000000000000000 R09: 0000000000000000 R10: ffff8801b164f610 R11: 0000000000000000 R12: 1ffff100362c9edc R13: 00000000ffffffff R14: 0000000000000001 R15: ffff8801ae924044 refcount_dec_and_test+0x1a/0x20 lib/refcount.c:212 put_net include/net/net_namespace.h:220 [inline] rpc_kill_sb+0x253/0x3c0 net/sunrpc/rpc_pipe.c:1473 deactivate_locked_super+0x88/0xd0 fs/super.c:312 sget_userns+0xbda/0xe40 fs/super.c:522 mount_ns+0x6d/0x190 fs/super.c:1029 rpc_mount+0x9e/0xd0 net/sunrpc/rpc_pipe.c:1451 mount_fs+0x66/0x2d0 fs/super.c:1222 vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:2509 [inline] do_new_mount fs/namespace.c:2512 [inline] do_mount+0xea4/0x2bb0 fs/namespace.c:2842 SYSC_mount fs/namespace.c:3058 [inline] SyS_mount+0xab/0x120 fs/namespace.c:3035 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4460f9 RSP: 002b:00007fbcd76dcd78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00000000006dcc3c RCX: 00000000004460f9 RDX: 0000000020000080 RSI: 0000000020000040 RDI: 0000000020000000 RBP: 00007fbcd76dcd80 R08: 00000000200000c0 R09: 0000000000003131 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc38 R13: ffffffffffffffff R14: 0000000000000028 R15: 0030656c69662f2e Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 86400 seconds..