[PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs

[PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs

[Alexander Gordeev]

Commit 2d6261583be0 ("lib: rework bitmap_parse()") does
not take into account order of halfwords on 64-bit big
endian architectures.

Fixes: 2d6261583be0 ("lib: rework bitmap_parse()")
Cc: stable@vger.kernel.org
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Amritha Nambiar <amritha.nambiar@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: "Tobin C . Harding" <tobin@kernel.org>
Cc: Vineet Gupta <vineet.gupta1@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
---
 lib/bitmap.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 89260aa..a725e46 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -717,6 +717,19 @@ static const char *bitmap_get_x32_reverse(const char *start,
 	return end;
 }
 
+#if defined(__BIG_ENDIAN) && defined(CONFIG_64BIT)
+static void save_x32_chunk(unsigned long *maskp, u32 chunk, int chunk_idx)
+{
+	maskp += (chunk_idx / 2);
+	((u32 *)maskp)[(chunk_idx & 1) ^ 1] = chunk;
+}
+#else
+static void save_x32_chunk(unsigned long *maskp, u32 chunk, int chunk_idx)
+{
+	((u32 *)maskp)[chunk_idx] = chunk;
+}
+#endif
+
 /**
  * bitmap_parse - convert an ASCII hex string into a bitmap.
  * @start: pointer to buffer containing string.
@@ -738,7 +751,8 @@ int bitmap_parse(const char *start, unsigned int buflen,
 {
 	const char *end = strnchrnul(start, buflen, '\n') - 1;
 	int chunks = BITS_TO_U32(nmaskbits);
-	u32 *bitmap = (u32 *)maskp;
+	int chunk_idx = 0;
+	u32 chunk;
 	int unset_bit;
 
 	while (1) {
@@ -749,9 +763,11 @@ int bitmap_parse(const char *start, unsigned int buflen,
 		if (!chunks--)
 			return -EOVERFLOW;
 
-		end = bitmap_get_x32_reverse(start, end, bitmap++);
+		end = bitmap_get_x32_reverse(start, end, &chunk);
 		if (IS_ERR(end))
 			return PTR_ERR(end);
+
+		save_x32_chunk(maskp, chunk, chunk_idx++);
 	}
 
 	unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
-- 
1.8.3.1

Re: [PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs

[Andy Shevchenko]

On Mon, May 18, 2020 at 1:40 PM Alexander Gordeev
<agordeev@linux.ibm.com> wrote:
>
> Commit 2d6261583be0 ("lib: rework bitmap_parse()") does
> not take into account order of halfwords on 64-bit big
> endian architectures.

Thanks for report and the patch!

Did it work before? Can we have a test case for that that we will see
the failure?

> Fixes: 2d6261583be0 ("lib: rework bitmap_parse()")
> Cc: stable@vger.kernel.org
> Cc: Yury Norov <yury.norov@gmail.com>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Amritha Nambiar <amritha.nambiar@intel.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Miklos Szeredi <mszeredi@redhat.com>
> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> Cc: Steffen Klassert <steffen.klassert@secunet.com>
> Cc: "Tobin C . Harding" <tobin@kernel.org>
> Cc: Vineet Gupta <vineet.gupta1@synopsys.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Willem de Bruijn <willemb@google.com>
> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
> ---
>  lib/bitmap.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 89260aa..a725e46 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -717,6 +717,19 @@ static const char *bitmap_get_x32_reverse(const char *start,
>         return end;
>  }
>
> +#if defined(__BIG_ENDIAN) && defined(CONFIG_64BIT)
> +static void save_x32_chunk(unsigned long *maskp, u32 chunk, int chunk_idx)
> +{
> +       maskp += (chunk_idx / 2);
> +       ((u32 *)maskp)[(chunk_idx & 1) ^ 1] = chunk;
> +}
> +#else
> +static void save_x32_chunk(unsigned long *maskp, u32 chunk, int chunk_idx)
> +{
> +       ((u32 *)maskp)[chunk_idx] = chunk;
> +}
> +#endif
> +
>  /**
>   * bitmap_parse - convert an ASCII hex string into a bitmap.
>   * @start: pointer to buffer containing string.
> @@ -738,7 +751,8 @@ int bitmap_parse(const char *start, unsigned int buflen,
>  {
>         const char *end = strnchrnul(start, buflen, '\n') - 1;
>         int chunks = BITS_TO_U32(nmaskbits);
> -       u32 *bitmap = (u32 *)maskp;
> +       int chunk_idx = 0;
> +       u32 chunk;
>         int unset_bit;
>
>         while (1) {
> @@ -749,9 +763,11 @@ int bitmap_parse(const char *start, unsigned int buflen,
>                 if (!chunks--)
>                         return -EOVERFLOW;
>
> -               end = bitmap_get_x32_reverse(start, end, bitmap++);
> +               end = bitmap_get_x32_reverse(start, end, &chunk);
>                 if (IS_ERR(end))
>                         return PTR_ERR(end);
> +
> +               save_x32_chunk(maskp, chunk, chunk_idx++);
>         }
>
>         unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
> --
> 1.8.3.1
>


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs

[Andy Shevchenko]

On Mon, May 18, 2020 at 2:33 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Mon, May 18, 2020 at 1:40 PM Alexander Gordeev
> <agordeev@linux.ibm.com> wrote:
> >
> > Commit 2d6261583be0 ("lib: rework bitmap_parse()") does
> > not take into account order of halfwords on 64-bit big
> > endian architectures.
>
> Thanks for report and the patch!
>
> Did it work before? Can we have a test case for that that we will see
> the failure?

Sorry, I wasn't clear enough. I meant a test case that is
arch-independent for this very issue (so, that I can run it on LE 64
machine and see a problem).

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs

[Alexander Gordeev]

On Mon, May 18, 2020 at 02:33:43PM +0300, Andy Shevchenko wrote:
> On Mon, May 18, 2020 at 1:40 PM Alexander Gordeev
> <agordeev@linux.ibm.com> wrote:
> >
> > Commit 2d6261583be0 ("lib: rework bitmap_parse()") does
> > not take into account order of halfwords on 64-bit big
> > endian architectures.
> 
> Thanks for report and the patch!
> 
> Did it work before? Can we have a test case for that that we will see
> the failure?

The test exists and enabled with CONFIG_TEST_BITMAP.
It does not appear ever passed before on 64 BE.
It does not fail on 64 LE for me either.

Thanks!

[...]

> -- 
> With Best Regards,
> Andy Shevchenko

Re: [PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs

[Alexander Gordeev]

On Mon, May 18, 2020 at 01:50:59PM +0200, Alexander Gordeev wrote:
> On Mon, May 18, 2020 at 02:33:43PM +0300, Andy Shevchenko wrote:
> > On Mon, May 18, 2020 at 1:40 PM Alexander Gordeev
> > <agordeev@linux.ibm.com> wrote:
> > >
> > > Commit 2d6261583be0 ("lib: rework bitmap_parse()") does
> > > not take into account order of halfwords on 64-bit big
> > > endian architectures.
> > 
> > Thanks for report and the patch!
> > 
> > Did it work before? Can we have a test case for that that we will see
> > the failure?
> 
> The test exists and enabled with CONFIG_TEST_BITMAP.
> It does not appear ever passed before on 64 BE.
> It does not fail on 64 LE for me either.

Hi Andy et al,

Any feedback on the fix? Does it work on 64 LE for you?

Thanks!

> Thanks!
> 
> [...]
> 
> > -- 
> > With Best Regards,
> > Andy Shevchenko

Re: [PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs

[Andy Shevchenko]

On Tue, Jun 02, 2020 at 12:24:31PM +0200, Alexander Gordeev wrote:
> On Mon, May 18, 2020 at 01:50:59PM +0200, Alexander Gordeev wrote:
> > On Mon, May 18, 2020 at 02:33:43PM +0300, Andy Shevchenko wrote:
> > > On Mon, May 18, 2020 at 1:40 PM Alexander Gordeev
> > > <agordeev@linux.ibm.com> wrote:
> > > >
> > > > Commit 2d6261583be0 ("lib: rework bitmap_parse()") does
> > > > not take into account order of halfwords on 64-bit big
> > > > endian architectures.
> > > 
> > > Thanks for report and the patch!
> > > 
> > > Did it work before? Can we have a test case for that that we will see
> > > the failure?
> > 
> > The test exists and enabled with CONFIG_TEST_BITMAP.
> > It does not appear ever passed before on 64 BE.
> > It does not fail on 64 LE for me either.
> 
> Hi Andy et al,
> 
> Any feedback on the fix? Does it work on 64 LE for you?

Test case, please.

Yes, you can simulate BE test case on LE platform and vise versa.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH RESEND] lib: fix bitmap_parse() on 64-bit big endian archs

[Alexander Gordeev]

On Fri, Jun 05, 2020 at 04:25:58PM +0300, Andy Shevchenko wrote:
> Test case, please.

Hi Andy,

Below is the output of the runtime kernel test "test_bitmap".
I resent the patch with Andrew Morton on CC, but did not include
the excessive test output:

test_bitmap: parse: 4: input is 1, result is 0x100000000, expected 0x1
test_bitmap: parse: 5: input is deadbeef, result is 0xdeadbeef00000000, expected 0xdeadbeef
test_bitmap: parse: 6: input is 1,0, result is 0x1, expected 0x100000000
test_bitmap: parse: 7: input is deadbeef,,0,1, result is 0x1, expected 0xdeadbeef
test_bitmap: parse: 8: input is deadbeef,1,0, result is 0x1, expected 0x100000000
test_bitmap: parse: 9: input is baadf00d,deadbeef,1,0, result is 0x1, expected 0x100000000
test_bitmap: parse: 10: input is badf00d,deadbeef,1,0, errno is -75, expected 0
test_bitmap: parse: 11: input is badf00d,deadbeef,1,0, errno is -75, expected 0
test_bitmap: parse: 12: input is   badf00d,deadbeef,1,0  , errno is -75, expected 0
test_bitmap: parse: 13: input is  , badf00d,deadbeef,1,0 , , errno is -75, expected 0
test_bitmap: parse: 14: input is  , badf00d, ,, ,,deadbeef,1,0 , , errno is -75, expected 0
test_bitmap: parse: 16: input is 3,0, errno is 0, expected -75
test_bitmap: parse_user: 4: input is 1, result is 0x100000000, expected 0x1
test_bitmap: parse_user: 5: input is deadbeef, result is 0xdeadbeef00000000, expected 0xdeadbeef
test_bitmap: parse_user: 6: input is 1,0, result is 0x1, expected 0x100000000
test_bitmap: parse_user: 7: input is deadbeef,,0,1, result is 0x1, expected 0xdeadbeef
test_bitmap: parse_user: 8: input is deadbeef,1,0, result is 0x1, expected 0x100000000
test_bitmap: parse_user: 9: input is baadf00d,deadbeef,1,0, result is 0x1, expected 0x100000000
test_bitmap: parse_user: 10: input is badf00d,deadbeef,1,0, errno is -75, expected 0
test_bitmap: parse_user: 11: input is badf00d,deadbeef,1,0, errno is -75, expected 0
test_bitmap: parse_user: 12: input is   badf00d,deadbeef,1,0  , errno is -75, expected 0
test_bitmap: parse_user: 13: input is  , badf00d,deadbeef,1,0 , , errno is -75, expected 0
test_bitmap: parse_user: 14: input is  , badf00d, ,, ,,deadbeef,1,0 , , errno is -75, expected 0
test_bitmap: parse_user: 16: input is 3,0, errno is 0, expected -75

Thanks!


> Yes, you can simulate BE test case on LE platform and vise versa.
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
>