patches for DPDK stable branches
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From: Thomas Monjalon <thomas@monjalon.net>
To: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: dev@dpdk.org, stable@dpdk.org
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] eal: fix end for bounded malloc elements
Date: Fri, 12 Jan 2018 15:54:33 +0100	[thread overview]
Message-ID: <17429603.yn0ZjX41h2@xps> (raw)
In-Reply-To: <be459294da93f5013e8a7be203a0253787224b2d.1513865614.git.anatoly.burakov@intel.com>

21/12/2017 17:54, Anatoly Burakov:
> In cases when alignment is bigger than boundary, we may incorrectly
> calculate end of a bounded malloc element.
> 
> Consider this: suppose we are allocating a bounded malloc element
> that should be of 128 bytes in size, bounded to 128 bytes and
> aligned on a 256-byte boundary. Suppose our malloc element ends
> at 0x140 - that is, 256 plus one cacheline.
> 
> So, right at the start, we are aligning our new_data_start to
> include the required element size, and to be aligned on a specified
> boundary - so new_data_start becomes 0. This fails the following
> bounds check, because our element cannot go above 128 bytes from
> the start, and we are at 320. So, we enter the bounds handling
> branch.
> 
> While we're in there, we are aligning end_pt to our boundedness
> requirement of 128 byte, and end up with 0x100 (since 256 is
> 128-byte aligned). We recalculate new_data_size and it stays at
> 0, however our end is at 0x100, which is beyond the 128 byte
> boundary, and we report inability to reserve a bounded element
> when we could have.
> 
> This patch adds an end_pt recalculation after new_data_start
> adjustment - we already know that size <= bound, so we can do it
> safely - and we then correctly report that we can, in fact, try
> using this element for bounded malloc allocation.
> 
> Fixes: fafcc11985a2 ("mem: rework memzone to be allocated by malloc")
> Cc: sergio.gonzalez.monroy@intel.com
> Cc: stable@dpdk.org
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>

It looks to be a headache, but as the maintainer of DPDK memory,
I trust you :)

Applied, thanks

      reply	other threads:[~2018-01-12 14:55 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-21 16:54 [dpdk-stable] " Anatoly Burakov
2018-01-12 14:54 ` Thomas Monjalon [this message]

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