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From: Johan Hovold <johan@kernel.org>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Johan Hovold <johan@kernel.org>, Rob Clark <robdclark@gmail.com>,
	Sean Paul <sean@poorly.run>,
	Fabien Dessenne <fabien.dessenne@st.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Harald Freudenberger <freude@linux.ibm.com>,
	David Airlie <airlied@linux.ie>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
	freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	linux-media@vger.kernel.org, linux-s390@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH 0/4] treewide: fix interrupted release
Date: Fri, 11 Oct 2019 11:36:33 +0200	[thread overview]
Message-ID: <20191011093633.GD27819@localhost> (raw)
In-Reply-To: <20191010135043.GA16989@phenom.ffwll.local>

On Thu, Oct 10, 2019 at 03:50:43PM +0200, Daniel Vetter wrote:
> On Thu, Oct 10, 2019 at 03:13:29PM +0200, Johan Hovold wrote:
> > Two old USB drivers had a bug in them which could lead to memory leaks
> > if an interrupted process raced with a disconnect event.
> > 
> > Turns out we had a few more driver in other subsystems with the same
> > kind of bug in them.

> Random funny idea: Could we do some debug annotations (akin to
> might_sleep) that splats when you might_sleep_interruptible somewhere
> where interruptible sleeps are generally a bad idea? Like in
> fops->release?

There's nothing wrong with interruptible sleep in fops->release per se,
it's just that drivers cannot return -ERESTARTSYS and friends and expect
to be called again later.

The return value from release() is ignored by vfs, and adding a splat in
__fput() to catch these buggy drivers might be overkill.

Johan

WARNING: multiple messages have this Message-ID (diff)
From: Johan Hovold <johan@kernel.org>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	freedreno@lists.freedesktop.org,
	Vasily Gorbik <gor@linux.ibm.com>,
	linux-s390@vger.kernel.org, David Airlie <airlied@linux.ie>,
	linux-arm-msm@vger.kernel.org,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Johan Hovold <johan@kernel.org>,
	Fabien Dessenne <fabien.dessenne@st.com>,
	linux-kernel@vger.kernel.org,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Harald Freudenberger <freude@linux.ibm.com>,
	dri-devel@lists.freedesktop.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Sean Paul <sean@poorly.run>,
	linux-media@vger.kernel.org
Subject: Re: [PATCH 0/4] treewide: fix interrupted release
Date: Fri, 11 Oct 2019 11:36:33 +0200	[thread overview]
Message-ID: <20191011093633.GD27819@localhost> (raw)
In-Reply-To: <20191010135043.GA16989@phenom.ffwll.local>

On Thu, Oct 10, 2019 at 03:50:43PM +0200, Daniel Vetter wrote:
> On Thu, Oct 10, 2019 at 03:13:29PM +0200, Johan Hovold wrote:
> > Two old USB drivers had a bug in them which could lead to memory leaks
> > if an interrupted process raced with a disconnect event.
> > 
> > Turns out we had a few more driver in other subsystems with the same
> > kind of bug in them.

> Random funny idea: Could we do some debug annotations (akin to
> might_sleep) that splats when you might_sleep_interruptible somewhere
> where interruptible sleeps are generally a bad idea? Like in
> fops->release?

There's nothing wrong with interruptible sleep in fops->release per se,
it's just that drivers cannot return -ERESTARTSYS and friends and expect
to be called again later.

The return value from release() is ignored by vfs, and adding a splat in
__fput() to catch these buggy drivers might be overkill.

Johan
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  reply	other threads:[~2019-10-11  9:36 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-10 13:13 [PATCH 0/4] treewide: fix interrupted release Johan Hovold
2019-10-10 13:13 ` [PATCH 1/4] drm/msm: fix memleak on release Johan Hovold
2019-10-30 10:01   ` Johan Hovold
2019-10-30 10:01     ` Johan Hovold
2019-10-30 10:01     ` Johan Hovold
2019-11-12 10:40     ` Johan Hovold
2019-11-12 10:40       ` Johan Hovold
2019-11-12 14:01       ` Daniel Vetter
2019-11-12 14:01         ` Daniel Vetter
2019-11-12 16:32         ` Rob Clark
2019-11-12 16:32           ` Rob Clark
2019-11-12 20:42           ` Sean Paul
2019-11-12 20:42             ` Sean Paul
2019-11-12 20:42             ` Sean Paul
2019-10-10 13:13 ` [PATCH 2/4] media: bdisp: " Johan Hovold
2019-10-10 13:13   ` Johan Hovold
2019-10-10 14:07   ` Fabien DESSENNE
2019-10-10 13:13 ` [PATCH 3/4] media: radio: wl1273: fix interrupt masking " Johan Hovold
2019-10-10 13:13 ` [PATCH 4/4] s390/zcrypt: fix memleak at release Johan Hovold
2019-10-10 13:13   ` Johan Hovold
2019-10-14  6:18   ` Heiko Carstens
2019-10-10 13:50 ` [PATCH 0/4] treewide: fix interrupted release Daniel Vetter
2019-10-10 13:50   ` Daniel Vetter
2019-10-11  9:36   ` Johan Hovold [this message]
2019-10-11  9:36     ` Johan Hovold
2019-10-14  8:48     ` Daniel Vetter
2019-10-14 16:13       ` Johan Hovold
2019-10-15 14:07         ` Daniel Vetter
2019-10-15 14:07           ` Daniel Vetter
2019-10-21  9:55           ` Johan Hovold
2019-10-21  9:55             ` Johan Hovold

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