From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: DMA: Fix kzalloc flags in __iommu_alloc_buffer()
Date: Mon, 08 Dec 2014 11:24 +0100 [thread overview]
Message-ID: <10532762.PXKTQM8KjH@wuerfel> (raw)
In-Reply-To: <1418027967-12923-1-git-send-email-acourbot@nvidia.com>
On Monday 08 December 2014 17:39:27 Alexandre Courbot wrote:
> There doesn't seem to be any valid reason to allocate the pages array
> with the same flags as the buffer itself. Doing so can eventually lead
> to the following safeguard in mm/slab.c to be hit:
>
> BUG_ON(flags & GFP_SLAB_BUG_MASK);
>
> This happens when buffers are allocated with __GFP_DMA32 or
> __GFP_HIGHMEM.
>
> Fix this by allocating the pages array with GFP_KERNEL to follow what is
> done elsewhere in this file. Using GFP_KERNEL in __iommu_alloc_buffer()
> is safe because atomic allocations are handled by __iommu_alloc_atomic().
>
I think you need to carry over the GFP_ATOMIC flag if that is set by the
caller, but not the GFP_HIGHMEM or GFP_DMA32. Not sure if it's better
to mask out flags from the caller mask, or to start with GFP_KERNEL
and adding in extra bits.
Arnd
next prev parent reply other threads:[~2014-12-08 10:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-08 8:39 [PATCH] ARM: DMA: Fix kzalloc flags in __iommu_alloc_buffer() Alexandre Courbot
2014-12-08 10:24 ` Arnd Bergmann [this message]
2014-12-09 2:57 ` Alexandre Courbot
2014-12-09 8:14 ` Arnd Bergmann
2014-12-11 11:12 ` Marek Szyprowski
2015-01-13 8:45 ` Alexandre Courbot
2015-01-13 11:20 ` Marek Szyprowski
2015-01-22 4:41 ` Alexandre Courbot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=10532762.PXKTQM8KjH@wuerfel \
--to=arnd@arndb.de \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox