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From: Alexander Potapenko <glider@google.com>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Marco Elver <elver@google.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	 Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	 kasan-dev <kasan-dev@googlegroups.com>,
	 Linux Memory Management List <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	 linux-s390 <linux-s390@vger.kernel.org>
Subject: Re: [PATCH 2/4] kfence: add function to mask address bits
Date: Thu, 29 Jul 2021 14:43:51 +0200	[thread overview]
Message-ID: <CAG_fn=VS_WFjL+qjm79Jvq5M0KaNScvX2vCw=aNxPx14Hffa0A@mail.gmail.com> (raw)
In-Reply-To: <20210728190254.3921642-3-hca@linux.ibm.com>

On Wed, Jul 28, 2021 at 9:03 PM Heiko Carstens <hca@linux.ibm.com> wrote:
>
> From: Sven Schnelle <svens@linux.ibm.com>
>
> s390 only reports the page address during a translation fault.
> To make the kfence unit tests pass, add a function that might
> be implemented by architectures to mask out address bits.
>
> Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
> ---
>  mm/kfence/kfence_test.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
> index 942cbc16ad26..eb6307c199ea 100644
> --- a/mm/kfence/kfence_test.c
> +++ b/mm/kfence/kfence_test.c
> @@ -23,8 +23,15 @@
>  #include <linux/tracepoint.h>
>  #include <trace/events/printk.h>
>
> +#include <asm/kfence.h>
> +
>  #include "kfence.h"
>
> +/* May be overridden by <asm/kfence.h>. */
> +#ifndef arch_kfence_test_address
> +#define arch_kfence_test_address(addr) (addr)
> +#endif
> +
>  /* Report as observed from console. */
>  static struct {
>         spinlock_t lock;
> @@ -82,6 +89,7 @@ static const char *get_access_type(const struct expect_report *r)
>  /* Check observed report matches information in @r. */
>  static bool report_matches(const struct expect_report *r)
>  {
> +       unsigned long addr = (unsigned long)r->addr;
>         bool ret = false;
>         unsigned long flags;
>         typeof(observed.lines) expect;
> @@ -131,22 +139,25 @@ static bool report_matches(const struct expect_report *r)
>         switch (r->type) {
>         case KFENCE_ERROR_OOB:
>                 cur += scnprintf(cur, end - cur, "Out-of-bounds %s at", get_access_type(r));
> +               addr = arch_kfence_test_address(addr);

Can we normalize addr once before (or after) this switch?

>                 break;
>         case KFENCE_ERROR_UAF:
>                 cur += scnprintf(cur, end - cur, "Use-after-free %s at", get_access_type(r));
> +               addr = arch_kfence_test_address(addr);
>                 break;
>         case KFENCE_ERROR_CORRUPTION:
>                 cur += scnprintf(cur, end - cur, "Corrupted memory at");
>                 break;
>         case KFENCE_ERROR_INVALID:
>                 cur += scnprintf(cur, end - cur, "Invalid %s at", get_access_type(r));
> +               addr = arch_kfence_test_address(addr);
>                 break;
>         case KFENCE_ERROR_INVALID_FREE:
>                 cur += scnprintf(cur, end - cur, "Invalid free of");
>                 break;
>         }
>
> -       cur += scnprintf(cur, end - cur, " 0x%p", (void *)r->addr);
> +       cur += scnprintf(cur, end - cur, " 0x%p", (void *)addr);
>
>         spin_lock_irqsave(&observed.lock, flags);
>         if (!report_available())
> --
> 2.25.1
>


-- 
Alexander Potapenko
Software Engineer

Google Germany GmbH
Erika-Mann-Straße, 33
80636 München

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  parent reply	other threads:[~2021-07-29 12:44 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-28 19:02 [PATCH 0/4] s390: add kfence support Heiko Carstens
2021-07-28 19:02 ` [PATCH 1/4] s390/mm: implement set_memory_4k() Heiko Carstens
2021-07-28 19:02 ` [PATCH 2/4] kfence: add function to mask address bits Heiko Carstens
2021-07-28 19:28   ` Christian Borntraeger
2021-07-29  7:48   ` Marco Elver
2021-07-29 12:25     ` Heiko Carstens
2021-07-29 12:27       ` Marco Elver
2021-07-29 12:43   ` Alexander Potapenko [this message]
2021-07-29 13:47     ` Sven Schnelle
2021-07-29 13:59       ` Alexander Potapenko
2021-07-28 19:02 ` [PATCH 3/4] s390: add support for KFENCE Heiko Carstens
2021-07-28 19:02 ` [PATCH 4/4] s390: add kfence region to pagetable dumper Heiko Carstens

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