From: Mark Rutland <mark.rutland@arm.com>
To: Matthew Wilcox <willy@infradead.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
Courtney Cavin <courtney.cavin@sonymobile.com>
Subject: Re: Preemptible idr_alloc() in QRTR code
Date: Tue, 26 Jan 2021 16:21:54 +0000 [thread overview]
Message-ID: <20210126162154.GD80448@C02TD0UTHF1T.local> (raw)
In-Reply-To: <20210126145833.GM308988@casper.infradead.org>
On Tue, Jan 26, 2021 at 02:58:33PM +0000, Matthew Wilcox wrote:
> On Tue, Jan 26, 2021 at 10:47:34AM +0000, Mark Rutland wrote:
> > Hi,
> >
> > When fuzzing arm64 with Syzkaller, I'm seeing some splats where
> > this_cpu_ptr() is used in the bowels of idr_alloc(), by way of
> > radix_tree_node_alloc(), in a preemptible context:
>
> I sent a patch to fix this last June. The maintainer seems to be
> under the impression that I care an awful lot more about their
> code than I do.
>
> https://lore.kernel.org/netdev/20200605120037.17427-1-willy@infradead.org/
Ah; I hadn't spotted the (glaringly obvious) GFP_ATOMIC abuse, thanks
for the pointer, and sorry for the noise.
It looks like Eric was after a fix that trivially backported to v4.7
(and hence couldn't rely on xarray) but instead it just got left broken
for months. :/
Bjorn, is this something you care about? You seem to have the most
commits to the file, and otherwise the official maintainer is Dave
Miller per get_maintainer.pl.
It is very tempting to make the config option depend on BROKEN...
Thanks,
Mark.
next prev parent reply other threads:[~2021-01-26 16:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 10:47 Preemptible idr_alloc() in QRTR code Mark Rutland
2021-01-26 14:58 ` Matthew Wilcox
2021-01-26 16:21 ` Mark Rutland [this message]
2021-01-26 17:00 ` Bjorn Andersson
2021-01-26 18:36 ` Mark Rutland
2021-01-27 0:41 ` Matthew Wilcox
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