From: Magnus Leatti <magnusleatti@kernelriot.com>
To: syzbot+9ef743bba3a17c756174@syzkaller.appspotmail.com
Cc: syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, oe-linux-nfc@lists.linux.dev,
David Heidelberg <david@ixit.cz>,
Johannes Berg <johannes@sipsolutions.net>,
Deepanshu Kartikey <kartikey406@gmail.com>
Subject: Re: [syzbot] INFO: task hung in rfkill_sync_work
Date: Thu, 12 Nov 2026 07:36:01 -0300 [thread overview]
Message-ID: <20261112103601.1848657-1-magnusleatti@kernelriot.com> (raw)
In-Reply-To: <000000000000788a6905f0c06160@google.com>
Hi,
This looks like the device_lock vs rfkill_global_mutex inversion
fixed by 1ab526d97a57 ("net: nfc: fix deadlock between
nfc_unregister_device and rfkill_fop_write"). That fix credited a
different syzbot report, so this one was never linked to it.
The report shows one task holding rfkill_global_mutex in
rfkill_fop_write and waiting for the NFC device lock in nfc_dev_down,
while another holds that device lock in nfc_unregister_device and
waits in rfkill_unregister. rfkill_sync_work is stuck behind them.
The C reproducer, 600 s per kernel, x86_64 under QEMU/KVM:
1ab526d97a57^ hung task report at 60 s
1ab526d97a57 no hang
9d66f26fefac no hang (mainline)
#syz fix: net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write
Thanks,
Magnus
prev parent reply other threads:[~2026-11-12 10:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-26 19:45 syzbot
2022-12-26 19:47 ` Johannes Berg
2023-01-26 14:18 ` syzbot
2026-11-12 10:36 ` Magnus Leatti [this message]
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