* [PATCH] mtd: sm_ftl: fix NULL pointer warning
@ 2020-01-07 21:24 Arnd Bergmann
2020-01-08 8:15 ` Miquel Raynal
2020-01-09 19:14 ` Miquel Raynal
0 siblings, 2 replies; 4+ messages in thread
From: Arnd Bergmann @ 2020-01-07 21:24 UTC (permalink / raw)
To: Miquel Raynal, Richard Weinberger, Vignesh Raghavendra
Cc: Oleksandr Natalenko, Arnd Bergmann, Wenwen Wang, linux-mtd, linux-kernel
With gcc -O3, we get a new warning:
In file included from arch/arm64/include/asm/processor.h:28,
from drivers/mtd/sm_ftl.c:8:
In function 'memset',
inlined from 'sm_read_sector.constprop' at drivers/mtd/sm_ftl.c:250:3:
include/linux/string.h:411:9: error: argument 1 null where non-null expected [-Werror=nonnull]
return __builtin_memset(p, c, size);
From all I can tell, this cannot happen (the function is called
either with a NULL buffer or with a -1 block number but not both),
but adding a check makes it more robust and avoids the warning.
Fixes: mmtom ("init/Kconfig: enable -O3 for all arches")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/mtd/sm_ftl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/sm_ftl.c b/drivers/mtd/sm_ftl.c
index 4744bf94ad9a..b9f272408c4d 100644
--- a/drivers/mtd/sm_ftl.c
+++ b/drivers/mtd/sm_ftl.c
@@ -247,7 +247,8 @@ static int sm_read_sector(struct sm_ftl *ftl,
/* FTL can contain -1 entries that are by default filled with bits */
if (block == -1) {
- memset(buffer, 0xFF, SM_SECTOR_SIZE);
+ if (buffer)
+ memset(buffer, 0xFF, SM_SECTOR_SIZE);
return 0;
}
--
2.20.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] mtd: sm_ftl: fix NULL pointer warning
2020-01-07 21:24 [PATCH] mtd: sm_ftl: fix NULL pointer warning Arnd Bergmann
@ 2020-01-08 8:15 ` Miquel Raynal
2020-01-08 8:18 ` Arnd Bergmann
2020-01-09 19:14 ` Miquel Raynal
1 sibling, 1 reply; 4+ messages in thread
From: Miquel Raynal @ 2020-01-08 8:15 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Richard Weinberger, Vignesh Raghavendra, Oleksandr Natalenko,
Wenwen Wang, linux-mtd, linux-kernel
Hi Arnd,
Arnd Bergmann <arnd@arndb.de> wrote on Tue, 7 Jan 2020 22:24:52 +0100:
> With gcc -O3, we get a new warning:
>
> In file included from arch/arm64/include/asm/processor.h:28,
> from drivers/mtd/sm_ftl.c:8:
> In function 'memset',
> inlined from 'sm_read_sector.constprop' at drivers/mtd/sm_ftl.c:250:3:
> include/linux/string.h:411:9: error: argument 1 null where non-null expected [-Werror=nonnull]
> return __builtin_memset(p, c, size);
>
> From all I can tell, this cannot happen (the function is called
> either with a NULL buffer or with a -1 block number but not both),
> but adding a check makes it more robust and avoids the warning.
>
> Fixes: mmtom ("init/Kconfig: enable -O3 for all arches")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/mtd/sm_ftl.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/sm_ftl.c b/drivers/mtd/sm_ftl.c
> index 4744bf94ad9a..b9f272408c4d 100644
> --- a/drivers/mtd/sm_ftl.c
> +++ b/drivers/mtd/sm_ftl.c
> @@ -247,7 +247,8 @@ static int sm_read_sector(struct sm_ftl *ftl,
>
> /* FTL can contain -1 entries that are by default filled with bits */
> if (block == -1) {
> - memset(buffer, 0xFF, SM_SECTOR_SIZE);
> + if (buffer)
> + memset(buffer, 0xFF, SM_SECTOR_SIZE);
> return 0;
> }
>
What about a simpler form:
if (buffer && block == -1) { ...
Instead of an additional indentation level?
Thanks,
Miquèl
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mtd: sm_ftl: fix NULL pointer warning
2020-01-08 8:15 ` Miquel Raynal
@ 2020-01-08 8:18 ` Arnd Bergmann
0 siblings, 0 replies; 4+ messages in thread
From: Arnd Bergmann @ 2020-01-08 8:18 UTC (permalink / raw)
To: Miquel Raynal
Cc: Richard Weinberger, Vignesh Raghavendra, Oleksandr Natalenko,
Wenwen Wang, linux-mtd, linux-kernel
On Wed, Jan 8, 2020 at 9:15 AM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
>
> Hi Arnd,
>
> Arnd Bergmann <arnd@arndb.de> wrote on Tue, 7 Jan 2020 22:24:52 +0100:
>
> > With gcc -O3, we get a new warning:
> >
> > In file included from arch/arm64/include/asm/processor.h:28,
> > from drivers/mtd/sm_ftl.c:8:
> > In function 'memset',
> > inlined from 'sm_read_sector.constprop' at drivers/mtd/sm_ftl.c:250:3:
> > include/linux/string.h:411:9: error: argument 1 null where non-null expected [-Werror=nonnull]
> > return __builtin_memset(p, c, size);
> >
> > From all I can tell, this cannot happen (the function is called
> > either with a NULL buffer or with a -1 block number but not both),
> > but adding a check makes it more robust and avoids the warning.
> >
> > Fixes: mmtom ("init/Kconfig: enable -O3 for all arches")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > drivers/mtd/sm_ftl.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/sm_ftl.c b/drivers/mtd/sm_ftl.c
> > index 4744bf94ad9a..b9f272408c4d 100644
> > --- a/drivers/mtd/sm_ftl.c
> > +++ b/drivers/mtd/sm_ftl.c
> > @@ -247,7 +247,8 @@ static int sm_read_sector(struct sm_ftl *ftl,
> >
> > /* FTL can contain -1 entries that are by default filled with bits */
> > if (block == -1) {
> > - memset(buffer, 0xFF, SM_SECTOR_SIZE);
> > + if (buffer)
> > + memset(buffer, 0xFF, SM_SECTOR_SIZE);
> > return 0;
> > }
> >
>
> What about a simpler form:
>
> if (buffer && block == -1) { ...
>
> Instead of an additional indentation level?
That would fail to return early from the function if we ever get block==-1
and buffer==NULL, probably resulting is worse problems later.
Arnd
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mtd: sm_ftl: fix NULL pointer warning
2020-01-07 21:24 [PATCH] mtd: sm_ftl: fix NULL pointer warning Arnd Bergmann
2020-01-08 8:15 ` Miquel Raynal
@ 2020-01-09 19:14 ` Miquel Raynal
1 sibling, 0 replies; 4+ messages in thread
From: Miquel Raynal @ 2020-01-09 19:14 UTC (permalink / raw)
To: Arnd Bergmann, Miquel Raynal, Richard Weinberger, Vignesh Raghavendra
Cc: Oleksandr Natalenko, Wenwen Wang, linux-mtd, linux-kernel
On Tue, 2020-01-07 at 21:24:52 UTC, Arnd Bergmann wrote:
> With gcc -O3, we get a new warning:
>
> In file included from arch/arm64/include/asm/processor.h:28,
> from drivers/mtd/sm_ftl.c:8:
> In function 'memset',
> inlined from 'sm_read_sector.constprop' at drivers/mtd/sm_ftl.c:250:3:
> include/linux/string.h:411:9: error: argument 1 null where non-null expected [-Werror=nonnull]
> return __builtin_memset(p, c, size);
>
> >From all I can tell, this cannot happen (the function is called
> either with a NULL buffer or with a -1 block number but not both),
> but adding a check makes it more robust and avoids the warning.
>
> Fixes: mmtom ("init/Kconfig: enable -O3 for all arches")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/fixes, thanks.
Miquel
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-01-08 8:15 ` Miquel Raynal
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2020-01-09 19:14 ` Miquel Raynal
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