netlink: 2 bytes leftover after parsing attributes in process `syz-executor5'.
============================================
WARNING: possible recursive locking detected
4.15.0-rc2-mm1+ #39 Not tainted
--------------------------------------------
syz-executor3/3809 is trying to acquire lock:
(rtnl_mutex){+.+.}, at: [<000000000f228262>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
but task is already holding lock:
(rtnl_mutex){+.+.}, at: [<000000000f228262>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(rtnl_mutex);
lock(rtnl_mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
1 lock held by syz-executor3/3809:
#0: (rtnl_mutex){+.+.}, at: [<000000000f228262>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
stack backtrace:
CPU: 1 PID: 3809 Comm: syz-executor3 Not tainted 4.15.0-rc2-mm1+ #39
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+0x194/0x257 lib/dump_stack.c:53
print_deadlock_bug kernel/locking/lockdep.c:1809 [inline]
check_deadlock kernel/locking/lockdep.c:1856 [inline]
validate_chain kernel/locking/lockdep.c:2457 [inline]
__lock_acquire+0x11cf/0x47f0 kernel/locking/lockdep.c:3500
lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
tun_free_netdev+0x158/0x1f0 drivers/net/tun.c:2068
register_netdevice+0x97b/0x1010 net/core/dev.c:7774
tun_set_iff drivers/net/tun.c:2389 [inline]
__tun_chr_ioctl+0x1ca3/0x3f10 drivers/net/tun.c:2613
tun_chr_ioctl+0x2a/0x40 drivers/net/tun.c:2866
vfs_ioctl fs/ioctl.c:46 [inline]
do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:686
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:00007ff9e830ac58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09
RDX: 0000000020927fd8 RSI: 00000000400454ca RDI: 0000000000000014
RBP: 0000000000000588 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f5560
R13: 00000000ffffffff R14: 00007ff9e830b6d4 R15: 0000000000000000