From: Johannes Berg <johannes@sipsolutions.net>
To: Walter Lozano <walter.lozano@collabora.com>,
linux-um@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: Sjoerd Simons <sjoerd.simons@collabora.com>,
ritesh sarraf <ritesh.sarraf@collabora.com>
Subject: Re: Occasional hung with UM after enable VMAP_STACK
Date: Tue, 04 Jan 2022 20:49:05 +0100 [thread overview]
Message-ID: <41fe09354fc736fb1ff2cb429e035633f24176ce.camel@sipsolutions.net> (raw)
In-Reply-To: <8c26a869-0cbe-a38c-8a8d-9f3f171f7e72@collabora.com>
On Tue, 2022-01-04 at 16:26 -0300, Walter Lozano wrote:
>
> Thank you for your quick response. The Debian configuration on package
> user-mode-linux have these settings
>
> CONFIG_HAVE_ARCH_VMAP_STACK=y
> CONFIG_VMAP_STACK=y
OK, so it actually _is_ enabled.
> as you can see in [1]. I did run some tests disabling those settings,
> which passed without any hung.
>
> Unfortunately the "occasional" behavior makes this issue a bit tricky to
> debug.
>
Right.
Hm. I've been running our tests with it for about three months and
haven't observed any hangs, but I guess that doesn't mean much.
To be honest, I have no particular reason to even want it, other than
that it catches accidental DMA from stack more easily ... so I guess if
we can't find anything, we might as well revert it.
Feels like it _should_ work though, since it's just a different location
for the stack.
johannes
WARNING: multiple messages have this Message-ID (diff)
From: Johannes Berg <johannes@sipsolutions.net>
To: Walter Lozano <walter.lozano@collabora.com>,
linux-um@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: Sjoerd Simons <sjoerd.simons@collabora.com>,
ritesh sarraf <ritesh.sarraf@collabora.com>
Subject: Re: Occasional hung with UM after enable VMAP_STACK
Date: Tue, 04 Jan 2022 20:49:05 +0100 [thread overview]
Message-ID: <41fe09354fc736fb1ff2cb429e035633f24176ce.camel@sipsolutions.net> (raw)
In-Reply-To: <8c26a869-0cbe-a38c-8a8d-9f3f171f7e72@collabora.com>
On Tue, 2022-01-04 at 16:26 -0300, Walter Lozano wrote:
>
> Thank you for your quick response. The Debian configuration on package
> user-mode-linux have these settings
>
> CONFIG_HAVE_ARCH_VMAP_STACK=y
> CONFIG_VMAP_STACK=y
OK, so it actually _is_ enabled.
> as you can see in [1]. I did run some tests disabling those settings,
> which passed without any hung.
>
> Unfortunately the "occasional" behavior makes this issue a bit tricky to
> debug.
>
Right.
Hm. I've been running our tests with it for about three months and
haven't observed any hangs, but I guess that doesn't mean much.
To be honest, I have no particular reason to even want it, other than
that it catches accidental DMA from stack more easily ... so I guess if
we can't find anything, we might as well revert it.
Feels like it _should_ work though, since it's just a different location
for the stack.
johannes
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next prev parent reply other threads:[~2022-01-04 19:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-04 18:10 Occasional hung with UM after enable VMAP_STACK Walter Lozano
2022-01-04 18:10 ` Walter Lozano
2022-01-04 19:04 ` Johannes Berg
2022-01-04 19:04 ` Johannes Berg
2022-01-04 19:26 ` Walter Lozano
2022-01-04 19:26 ` Walter Lozano
2022-01-04 19:49 ` Johannes Berg [this message]
2022-01-04 19:49 ` Johannes Berg
2022-01-05 12:58 ` Walter Lozano
2022-01-05 12:58 ` Walter Lozano
2022-01-04 21:39 ` Anton Ivanov
2022-01-04 21:39 ` Anton Ivanov
2022-01-05 12:59 ` Walter Lozano
2022-01-05 12:59 ` Walter Lozano
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