From: Pete Eberlein <pete@sensoray.com>
To: linux-media <linux-media@vger.kernel.org>
Cc: viro@ZenIV.linux.org.uk, mchehab@redhat.com
Subject: videobuf mmap deadlock
Date: Fri, 01 Nov 2013 11:54:42 -0700 [thread overview]
Message-ID: <5273F8F2.5070901@sensoray.com> (raw)
The patch "videobuf_vm_{open,close} race fixes"
https://linuxtv.org/patch/18365/ introduced a deadlock in 3.11.
My driver uses videobuf_vmalloc initialized with ext_lock set to NULL.
My driver's mmap function calls videobuf_mmap_mapper
videobuf_mmap_mapper calls videobuf_queue_lock on q
videobuf_mmap_mapper calls __videobuf_mmap_mapper
__videobuf_mmap_mapper calls videobuf_vm_open
videobuf_vm_open calls videobuf_queue_lock on q (introduced by above patch)
deadlocked
This is not an issue if ext_lock is non-NULL, since videobuf_queue_lock
is a no-op in that case.
Did I do something wrong, or is this a valid regression?
Regards,
Pete Eberlein
next reply other threads:[~2013-11-01 19:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-01 18:54 Pete Eberlein [this message]
2013-11-11 12:29 ` videobuf mmap deadlock Hans Verkuil
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