* [PATCH mm v2] mm, kasan: fix for "integrate page_alloc init with HW_TAGS"
@ 2021-03-30 16:37 Andrey Konovalov
2021-03-30 16:44 ` Vlastimil Babka
0 siblings, 1 reply; 3+ messages in thread
From: Andrey Konovalov @ 2021-03-30 16:37 UTC (permalink / raw)
To: Andrew Morton
Cc: Vlastimil Babka, Sergei Trofimovich, Alexander Potapenko,
Marco Elver, Dmitry Vyukov, Andrey Ryabinin, Andrey Konovalov,
kasan-dev, linux-mm, linux-kernel, Andrey Konovalov
My commit "integrate page_alloc init with HW_TAGS" changed the order of
kernel_unpoison_pages() and kernel_init_free_pages() calls. This leads
to complaints from the page unpoisoning code, as the poison pattern gets
overwritten for __GFP_ZERO allocations.
Fix by restoring the initial order. Also add a warning comment.
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
mm/page_alloc.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 033bd92e8398..d2c020563c0b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2328,6 +2328,13 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
arch_alloc_page(page, order);
debug_pagealloc_map_pages(page, 1 << order);
+ /*
+ * Page unpoisoning must happen before memory initialization.
+ * Otherwise, the poison pattern will be overwritten for __GFP_ZERO
+ * allocations and the page unpoisoning code will complain.
+ */
+ kernel_unpoison_pages(page, 1 << order);
+
/*
* As memory initialization might be integrated into KASAN,
* kasan_alloc_pages and kernel_init_free_pages must be
@@ -2338,7 +2345,6 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
if (init && !kasan_has_integrated_init())
kernel_init_free_pages(page, 1 << order);
- kernel_unpoison_pages(page, 1 << order);
set_page_owner(page, order, gfp_flags);
}
--
2.31.0.291.g576ba9dcdaf-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH mm v2] mm, kasan: fix for "integrate page_alloc init with HW_TAGS"
2021-03-30 16:37 [PATCH mm v2] mm, kasan: fix for "integrate page_alloc init with HW_TAGS" Andrey Konovalov
@ 2021-03-30 16:44 ` Vlastimil Babka
2021-03-30 18:11 ` Sergei Trofimovich
0 siblings, 1 reply; 3+ messages in thread
From: Vlastimil Babka @ 2021-03-30 16:44 UTC (permalink / raw)
To: Andrey Konovalov, Andrew Morton
Cc: Sergei Trofimovich, Alexander Potapenko, Marco Elver,
Dmitry Vyukov, Andrey Ryabinin, Andrey Konovalov, kasan-dev,
linux-mm, linux-kernel
On 3/30/21 6:37 PM, Andrey Konovalov wrote:
> My commit "integrate page_alloc init with HW_TAGS" changed the order of
> kernel_unpoison_pages() and kernel_init_free_pages() calls. This leads
> to complaints from the page unpoisoning code, as the poison pattern gets
> overwritten for __GFP_ZERO allocations.
>
> Fix by restoring the initial order. Also add a warning comment.
>
> Reported-by: Vlastimil Babka <vbabka@suse.cz>
> Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Tested that the bug indeed occurs in -next and is fixed by this. Thanks.
> ---
> mm/page_alloc.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 033bd92e8398..d2c020563c0b 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2328,6 +2328,13 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
> arch_alloc_page(page, order);
> debug_pagealloc_map_pages(page, 1 << order);
>
> + /*
> + * Page unpoisoning must happen before memory initialization.
> + * Otherwise, the poison pattern will be overwritten for __GFP_ZERO
> + * allocations and the page unpoisoning code will complain.
> + */
> + kernel_unpoison_pages(page, 1 << order);
> +
> /*
> * As memory initialization might be integrated into KASAN,
> * kasan_alloc_pages and kernel_init_free_pages must be
> @@ -2338,7 +2345,6 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
> if (init && !kasan_has_integrated_init())
> kernel_init_free_pages(page, 1 << order);
>
> - kernel_unpoison_pages(page, 1 << order);
> set_page_owner(page, order, gfp_flags);
> }
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH mm v2] mm, kasan: fix for "integrate page_alloc init with HW_TAGS"
2021-03-30 16:44 ` Vlastimil Babka
@ 2021-03-30 18:11 ` Sergei Trofimovich
0 siblings, 0 replies; 3+ messages in thread
From: Sergei Trofimovich @ 2021-03-30 18:11 UTC (permalink / raw)
To: Vlastimil Babka
Cc: Andrey Konovalov, Andrew Morton, Alexander Potapenko,
Marco Elver, Dmitry Vyukov, Andrey Ryabinin, Andrey Konovalov,
kasan-dev, linux-mm, linux-kernel
On Tue, 30 Mar 2021 18:44:09 +0200
Vlastimil Babka <vbabka@suse.cz> wrote:
> On 3/30/21 6:37 PM, Andrey Konovalov wrote:
> > My commit "integrate page_alloc init with HW_TAGS" changed the order of
> > kernel_unpoison_pages() and kernel_init_free_pages() calls. This leads
> > to complaints from the page unpoisoning code, as the poison pattern gets
> > overwritten for __GFP_ZERO allocations.
> >
> > Fix by restoring the initial order. Also add a warning comment.
> >
> > Reported-by: Vlastimil Babka <vbabka@suse.cz>
> > Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
>
> Tested that the bug indeed occurs in -next and is fixed by this. Thanks.
Reviewed-by: Sergei Trofimovich <slyfox@gentoo.org>
> > ---
> > mm/page_alloc.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index 033bd92e8398..d2c020563c0b 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -2328,6 +2328,13 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
> > arch_alloc_page(page, order);
> > debug_pagealloc_map_pages(page, 1 << order);
> >
> > + /*
> > + * Page unpoisoning must happen before memory initialization.
> > + * Otherwise, the poison pattern will be overwritten for __GFP_ZERO
> > + * allocations and the page unpoisoning code will complain.
> > + */
> > + kernel_unpoison_pages(page, 1 << order);
> > +
> > /*
> > * As memory initialization might be integrated into KASAN,
> > * kasan_alloc_pages and kernel_init_free_pages must be
> > @@ -2338,7 +2345,6 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
> > if (init && !kasan_has_integrated_init())
> > kernel_init_free_pages(page, 1 << order);
> >
> > - kernel_unpoison_pages(page, 1 << order);
> > set_page_owner(page, order, gfp_flags);
> > }
> >
> >
>
--
Sergei
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-03-30 18:12 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-30 16:37 [PATCH mm v2] mm, kasan: fix for "integrate page_alloc init with HW_TAGS" Andrey Konovalov
2021-03-30 16:44 ` Vlastimil Babka
2021-03-30 18:11 ` Sergei Trofimovich
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).