From: Andrew Morton <akpm@linux-foundation.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Michal Hocko <mhocko@suse.com>,
Peter Zijlstra <peterz@infraded.org>,
Rik van Riel <riel@redhat.com>, Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH] Detect early free of a live mm
Date: Thu, 1 Mar 2018 17:16:09 -0800 [thread overview]
Message-ID: <20180301171609.c1968b89a15320186122e34e@linux-foundation.org> (raw)
In-Reply-To: <20180228121458.2230-1-mark.rutland@arm.com>
On Wed, 28 Feb 2018 12:14:58 +0000 Mark Rutland <mark.rutland@arm.com> wrote:
> KASAN splats indicate that in some cases we free a live mm, then
> continue to access it, with potentially disastrous results. This is
> likely due to a mismatched mmdrop() somewhere in the kernel, but so far
> the culprit remains elusive.
>
> Let's have __mmdrop() verify that the mm isn't live for the current
> task, similar to the existing check for init_mm. This way, we can catch
> this class of issue earlier, and without requiring KASAN.
Presumably the results usually aren't disastrous. But they will be if
we go and add BUG_ON()s! Can we make this WARN_ON[_ONCE]()? We should
still get the same info from testers.
next prev parent reply other threads:[~2018-03-02 1:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-28 12:14 [PATCH] Detect early free of a live mm Mark Rutland
2018-02-28 12:18 ` Mark Rutland
2018-03-01 9:35 ` Michal Hocko
2018-03-01 11:22 ` Mark Rutland
2018-03-01 12:40 ` Michal Hocko
2018-03-01 12:49 ` Mark Rutland
2018-03-02 1:16 ` Andrew Morton [this message]
2018-03-02 10:24 ` Mark Rutland
2018-03-09 21:11 ` 94d3a25408: kernel_BUG_at_kernel/fork.c kernel test robot
2018-03-12 13:46 ` Mark Rutland
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