From: Amit Shah <amit.shah@redhat.com>
To: Omar Sandoval <osandov@osandov.com>
Cc: virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH] virtio-console: avoid DMA from stack
Date: Wed, 1 Feb 2017 19:17:12 +0530 [thread overview]
Message-ID: <20170201134712.GA7935@amit-lp.rh> (raw)
In-Reply-To: <075115ddd99246ffc4228a3e050ba68eb36c6a8c.1485935920.git.osandov@fb.com>
On (Wed) 01 Feb 2017 [00:02:27], Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
>
> put_chars() stuffs the buffer it gets into an sg, but that buffer may be
> on the stack. This breaks with CONFIG_VMAP_STACK=y (for me, it
> manifested as printks getting turned into NUL bytes).
Seems reasonable. I wonder since all implementations of hvc do a
memcpy, if we can abstract it - but that'll need some work.
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Michael, please add to the virtio queue.
Amit
WARNING: multiple messages have this Message-ID (diff)
From: Amit Shah <amit.shah@redhat.com>
To: Omar Sandoval <osandov@osandov.com>
Cc: kernel-team@fb.com, "Michael S. Tsirkin" <mst@redhat.com>,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH] virtio-console: avoid DMA from stack
Date: Wed, 1 Feb 2017 19:17:12 +0530 [thread overview]
Message-ID: <20170201134712.GA7935@amit-lp.rh> (raw)
In-Reply-To: <075115ddd99246ffc4228a3e050ba68eb36c6a8c.1485935920.git.osandov@fb.com>
On (Wed) 01 Feb 2017 [00:02:27], Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
>
> put_chars() stuffs the buffer it gets into an sg, but that buffer may be
> on the stack. This breaks with CONFIG_VMAP_STACK=y (for me, it
> manifested as printks getting turned into NUL bytes).
Seems reasonable. I wonder since all implementations of hvc do a
memcpy, if we can abstract it - but that'll need some work.
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Michael, please add to the virtio queue.
Amit
next prev parent reply other threads:[~2017-02-01 13:47 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-01 8:02 [PATCH] virtio-console: avoid DMA from stack Omar Sandoval
2017-02-01 8:02 ` Omar Sandoval
2017-02-01 13:47 ` Amit Shah [this message]
2017-02-01 13:47 ` Amit Shah
2017-03-01 20:01 ` Omar Sandoval
2017-03-01 20:01 ` Omar Sandoval
2017-03-01 21:25 ` Michael S. Tsirkin
2017-03-01 21:25 ` Michael S. Tsirkin
2017-03-03 0:58 ` Jan Dakinevich
2017-03-03 0:58 ` Jan Dakinevich
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