[syzbot] possible deadlock in cfg80211_netdev_notifier_call (2)

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syzbot

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May 10, 2021, 8:20:21 AMMay 10
to da...@davemloft.net, joha...@sipsolutions.net, ku...@kernel.org, linux-...@vger.kernel.org, linux-w...@vger.kernel.org, net...@vger.kernel.org, syzkall...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: b7415964 Merge tag 'riscv-for-linus-5.13-mw1' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1240ba0dd00000
kernel config: https://syzkaller.appspot.com/x/.config?x=b072be26137971e1
dashboard link: https://syzkaller.appspot.com/bug?extid=452ea4fbbef700ff0a56

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+452ea4...@syzkaller.appspotmail.com

============================================
WARNING: possible recursive locking detected
5.12.0-syzkaller #0 Not tainted
--------------------------------------------
syz-executor.1/16085 is trying to acquire lock:
ffff88804f3b05e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5273 [inline]
ffff88804f3b05e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_netdev_notifier_call+0x704/0x11d0 net/wireless/core.c:1429

but task is already holding lock:
ffff88804f3b05e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5273 [inline]
ffff88804f3b05e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: ieee80211_stop+0x6a/0xf0 net/mac80211/iface.c:644

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&rdev->wiphy.mtx);
lock(&rdev->wiphy.mtx);

*** DEADLOCK ***

May be due to missing lock nesting notation

2 locks held by syz-executor.1/16085:
#0: ffffffff8d6a4968 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x19f/0xb70 net/core/dev_ioctl.c:504
#1: ffff88804f3b05e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5273 [inline]
#1: ffff88804f3b05e8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: ieee80211_stop+0x6a/0xf0 net/mac80211/iface.c:644

stack backtrace:
CPU: 0 PID: 16085 Comm: syz-executor.1 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
print_deadlock_bug kernel/locking/lockdep.c:2831 [inline]
check_deadlock kernel/locking/lockdep.c:2874 [inline]
validate_chain kernel/locking/lockdep.c:3663 [inline]
__lock_acquire.cold+0x22f/0x3b4 kernel/locking/lockdep.c:4902
lock_acquire kernel/locking/lockdep.c:5512 [inline]
lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5477
__mutex_lock_common kernel/locking/mutex.c:949 [inline]
__mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
wiphy_lock include/net/cfg80211.h:5273 [inline]
cfg80211_netdev_notifier_call+0x704/0x11d0 net/wireless/core.c:1429
notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2121
call_netdevice_notifiers_extack net/core/dev.c:2133 [inline]
call_netdevice_notifiers net/core/dev.c:2147 [inline]
__dev_close_many+0xf3/0x2f0 net/core/dev.c:1667
dev_close_many+0x22c/0x620 net/core/dev.c:1718
dev_close net/core/dev.c:1744 [inline]
dev_close+0x16d/0x210 net/core/dev.c:1738
ieee80211_do_stop+0x1276/0x20e0 net/mac80211/iface.c:486
ieee80211_stop+0x77/0xf0 net/mac80211/iface.c:645
__dev_close_many+0x1b8/0x2f0 net/core/dev.c:1693
__dev_close net/core/dev.c:1705 [inline]
__dev_change_flags+0x2ca/0x750 net/core/dev.c:8739
dev_change_flags+0x93/0x170 net/core/dev.c:8812
dev_ifsioc+0x210/0xa60 net/core/dev_ioctl.c:254
dev_ioctl+0x1ad/0xb70 net/core/dev_ioctl.c:505
sock_do_ioctl+0x148/0x2d0 net/socket.c:1062
sock_ioctl+0x477/0x6a0 net/socket.c:1179
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:1069 [inline]
__se_sys_ioctl fs/ioctl.c:1055 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:1055
do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665f9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f59aeea3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665f9
RDX: 00000000200005c0 RSI: 0000000000008914 RDI: 0000000000000003
RBP: 00000000004bfce1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 0000000000a9fb1f R14: 00007f59aeea3300 R15: 0000000000022000


---
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