From: Andrey Konovalov <andreyknvl@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Peter Collingbourne <pcc@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Christoph Hellwig <hch@infradead.org>,
kasan-dev <kasan-dev@googlegroups.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
Date: Fri, 5 Mar 2021 18:04:27 +0100 [thread overview]
Message-ID: <CAAeHK+wyh=vpw=Gbi+NqZ0A1z-0a8pQS8q0OkOfLc9o=zhMEUA@mail.gmail.com> (raw)
In-Reply-To: <1aa83e48627978de8068d5e3314185f3a0d7a849.1614302398.git.andreyknvl@google.com>
On Fri, Feb 26, 2021 at 2:25 AM Andrey Konovalov <andreyknvl@google.com> wrote:
>
> Currently, kasan_free_nondeferred_pages()->kasan_free_pages() is called
> after debug_pagealloc_unmap_pages(). This causes a crash when
> debug_pagealloc is enabled, as HW_TAGS KASAN can't set tags on an
> unmapped page.
>
> This patch puts kasan_free_nondeferred_pages() before
> debug_pagealloc_unmap_pages().
>
> Besides fixing the crash, this also makes the annotation order consistent
> with debug_pagealloc_map_pages() preceding kasan_alloc_pages().
>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---
> mm/page_alloc.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index c89e7b107514..54bc237fd319 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1311,10 +1311,14 @@ static __always_inline bool free_pages_prepare(struct page *page,
> */
> arch_free_page(page, order);
>
> - debug_pagealloc_unmap_pages(page, 1 << order);
> -
> + /*
> + * With hardware tag-based KASAN, memory tags must be set
> + * before unmapping the page with debug_pagealloc.
> + */
> kasan_free_nondeferred_pages(page, order, fpi_flags);
Looking at this again, I think we need to move kasan_() callback above
arch_free_page(), as that can also make the page unavailable. I'll
send v2.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
prev parent reply other threads:[~2021-03-05 17:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 1:25 [PATCH] kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC Andrey Konovalov
2021-03-03 23:23 ` Andrew Morton
2021-03-05 15:43 ` Andrey Konovalov
2021-03-05 17:04 ` Andrey Konovalov [this message]
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='CAAeHK+wyh=vpw=Gbi+NqZ0A1z-0a8pQS8q0OkOfLc9o=zhMEUA@mail.gmail.com' \
--to=andreyknvl@google.com \
--cc=Branislav.Rankov@arm.com \
--cc=akpm@linux-foundation.org \
--cc=aryabinin@virtuozzo.com \
--cc=catalin.marinas@arm.com \
--cc=dvyukov@google.com \
--cc=elver@google.com \
--cc=eugenis@google.com \
--cc=glider@google.com \
--cc=hch@infradead.org \
--cc=kasan-dev@googlegroups.com \
--cc=kevin.brodsky@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=pcc@google.com \
--cc=vincenzo.frascino@arm.com \
--cc=will.deacon@arm.com \
/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;
as well as URLs for NNTP newsgroup(s).