All of lore.kernel.org
 help / color / mirror / Atom feed
From: Catalin Marinas <catalin.marinas@arm.com>
To: Qian Cai <quic_qiancai@quicinc.com>
Cc: Mike Rapoport <rppt@kernel.org>, Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: Track no early_pgtable_alloc() for kmemleak
Date: Fri, 5 Nov 2021 10:08:05 +0000	[thread overview]
Message-ID: <YYUChdTeXP/OQUwS@arm.com> (raw)
In-Reply-To: <9bb6fe11-c10a-a373-9288-d44a5ba976fa@quicinc.com>

On Thu, Nov 04, 2021 at 01:57:03PM -0400, Qian Cai wrote:
> On 11/4/21 1:06 PM, Mike Rapoport wrote:
> > I think I'll be better to rename MEMBLOCK_ALLOC_KASAN to, say,
> > MEMBLOCK_ALLOC_NOKMEMLEAK and use that for both KASAN and page table cases.
> 
> Okay, that would look a bit nicer.

Or MEMBLOCK_ALLOC_ACCESSIBLE_NOLEAKTRACE to match SLAB_NOLEAKTRACE and
also hint that it's accessible memory.

> > But more generally, we are going to hit this again and again.
> > Couldn't we add a memblock allocation as a mean to get more memory to
> > kmemleak::mem_pool_alloc()?
> 
> For the last 5 years, this is the second time I am ware of this kind of
> issue just because of the 64KB->4KB switch on those servers, although I
> agree it could happen again in the future due to some new debugging
> features etc. I don't feel a strong need to rewrite it now though. Not
> sure if Catalin saw things differently. Anyway, Mike, do you agree that
> we could rewrite that separately in the future?

I was talking to Mike on IRC last night and I think you still need a
flag, otherwise you could get a recursive memblock -> kmemleak ->
memblock call (that's why we have SLAB_NOLEAKTRACE). So for the time
being, a new MEMBLOCK_* definition would do.

I wonder whether we could actually use the bottom bits in the end/limit
as actual flags so one can do (MEMBLOCK_ALLOC_ACCESSIBLE |
MEMBLOCK_NOLEAKTRACE). But that could be for a separate clean-up.

-- 
Catalin

WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com>
To: Qian Cai <quic_qiancai@quicinc.com>
Cc: Mike Rapoport <rppt@kernel.org>, Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: Track no early_pgtable_alloc() for kmemleak
Date: Fri, 5 Nov 2021 10:08:05 +0000	[thread overview]
Message-ID: <YYUChdTeXP/OQUwS@arm.com> (raw)
In-Reply-To: <9bb6fe11-c10a-a373-9288-d44a5ba976fa@quicinc.com>

On Thu, Nov 04, 2021 at 01:57:03PM -0400, Qian Cai wrote:
> On 11/4/21 1:06 PM, Mike Rapoport wrote:
> > I think I'll be better to rename MEMBLOCK_ALLOC_KASAN to, say,
> > MEMBLOCK_ALLOC_NOKMEMLEAK and use that for both KASAN and page table cases.
> 
> Okay, that would look a bit nicer.

Or MEMBLOCK_ALLOC_ACCESSIBLE_NOLEAKTRACE to match SLAB_NOLEAKTRACE and
also hint that it's accessible memory.

> > But more generally, we are going to hit this again and again.
> > Couldn't we add a memblock allocation as a mean to get more memory to
> > kmemleak::mem_pool_alloc()?
> 
> For the last 5 years, this is the second time I am ware of this kind of
> issue just because of the 64KB->4KB switch on those servers, although I
> agree it could happen again in the future due to some new debugging
> features etc. I don't feel a strong need to rewrite it now though. Not
> sure if Catalin saw things differently. Anyway, Mike, do you agree that
> we could rewrite that separately in the future?

I was talking to Mike on IRC last night and I think you still need a
flag, otherwise you could get a recursive memblock -> kmemleak ->
memblock call (that's why we have SLAB_NOLEAKTRACE). So for the time
being, a new MEMBLOCK_* definition would do.

I wonder whether we could actually use the bottom bits in the end/limit
as actual flags so one can do (MEMBLOCK_ALLOC_ACCESSIBLE |
MEMBLOCK_NOLEAKTRACE). But that could be for a separate clean-up.

-- 
Catalin

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-11-05 10:08 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-04 15:56 [PATCH] arm64: Track no early_pgtable_alloc() for kmemleak Qian Cai
2021-11-04 15:56 ` Qian Cai
2021-11-04 17:06 ` Mike Rapoport
2021-11-04 17:06   ` Mike Rapoport
2021-11-04 17:57   ` Qian Cai
2021-11-04 17:57     ` Qian Cai
2021-11-05 10:08     ` Catalin Marinas [this message]
2021-11-05 10:08       ` Catalin Marinas
2021-11-05 11:05       ` Mike Rapoport
2021-11-05 11:05         ` Mike Rapoport
2021-11-05 10:49     ` Mike Rapoport
2021-11-05 10:49       ` Mike Rapoport
2021-11-04 17:09 ` Catalin Marinas
2021-11-04 17:09   ` Catalin Marinas

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=YYUChdTeXP/OQUwS@arm.com \
    --to=catalin.marinas@arm.com \
    --cc=akpm@linux-foundation.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=quic_qiancai@quicinc.com \
    --cc=rppt@kernel.org \
    --cc=will@kernel.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.