* + mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch added to -mm tree
@ 2022-02-01 19:34 Andrew Morton
2022-02-02 0:34 ` Waiman Long
0 siblings, 1 reply; 5+ messages in thread
From: Andrew Morton @ 2022-02-01 19:34 UTC (permalink / raw)
To: mm-commits, mingo, kirill.shutemov, jforbes, aquini, longman, akpm
The patch titled
Subject: mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning
has been added to the -mm tree. Its filename is
mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Waiman Long <longman@redhat.com>
Subject: mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning
The gcc 12 compiler reports a warning on the following code:
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
#ifdef CONFIG_SPARSEMEM_EXTREME
if (!mem_section)
return NULL;
#endif
:
With CONFIG_SPARSEMEM_EXTREME on, the mem_section definition is
extern struct mem_section **mem_section;
Obviously, mem_section cannot be NULL, but *mem_section can be if memory
hasn't been allocated for the dynamic mem_section[] array yet. Fix this
warning by checking for "!*mem_section" instead.
Link: https://lkml.kernel.org/r/20220201192924.672675-1-longman@redhat.com
Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Justin Forbes <jforbes@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/mmzone.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/mmzone.h~mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning
+++ a/include/linux/mmzone.h
@@ -1390,7 +1390,7 @@ static inline unsigned long *section_to_
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
#ifdef CONFIG_SPARSEMEM_EXTREME
- if (!mem_section)
+ if (!*mem_section)
return NULL;
#endif
if (!mem_section[SECTION_NR_TO_ROOT(nr)])
_
Patches currently in -mm which might be from longman@redhat.com are
mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
ipc-mqueue-use-get_tree_nodev-in-mqueue_get_tree.patch
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: + mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch added to -mm tree
2022-02-01 19:34 + mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch added to -mm tree Andrew Morton
@ 2022-02-02 0:34 ` Waiman Long
0 siblings, 0 replies; 5+ messages in thread
From: Waiman Long @ 2022-02-02 0:34 UTC (permalink / raw)
To: Andrew Morton, mm-commits, mingo, kirill.shutemov, jforbes, aquini
On 2/1/22 14:34, Andrew Morton wrote:
> The patch titled
> Subject: mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning
> has been added to the -mm tree. Its filename is
> mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
>
> This patch should soon appear at
> https://ozlabs.org/~akpm/mmots/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
> and later at
> https://ozlabs.org/~akpm/mmotm/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
>
> Before you just go and hit "reply", please:
> a) Consider who else should be cc'ed
> b) Prefer to cc a suitable mailing list as well
> c) Ideally: find the original patch on the mailing list and do a
> reply-to-all to that, adding suitable additional cc's
>
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
>
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
>
> ------------------------------------------------------
> From: Waiman Long <longman@redhat.com>
> Subject: mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning
>
> The gcc 12 compiler reports a warning on the following code:
>
> static inline struct mem_section *__nr_to_section(unsigned long nr)
> {
> #ifdef CONFIG_SPARSEMEM_EXTREME
> if (!mem_section)
> return NULL;
> #endif
> :
>
> With CONFIG_SPARSEMEM_EXTREME on, the mem_section definition is
>
> extern struct mem_section **mem_section;
>
> Obviously, mem_section cannot be NULL, but *mem_section can be if memory
> hasn't been allocated for the dynamic mem_section[] array yet. Fix this
> warning by checking for "!*mem_section" instead.
>
> Link: https://lkml.kernel.org/r/20220201192924.672675-1-longman@redhat.com
> Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
> Signed-off-by: Waiman Long <longman@redhat.com>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Justin Forbes <jforbes@redhat.com>
> Cc: Rafael Aquini <aquini@redhat.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
> include/linux/mmzone.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/include/linux/mmzone.h~mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning
> +++ a/include/linux/mmzone.h
> @@ -1390,7 +1390,7 @@ static inline unsigned long *section_to_
> static inline struct mem_section *__nr_to_section(unsigned long nr)
> {
> #ifdef CONFIG_SPARSEMEM_EXTREME
> - if (!mem_section)
> + if (!*mem_section)
> return NULL;
> #endif
> if (!mem_section[SECTION_NR_TO_ROOT(nr)])
> _
>
> Patches currently in -mm which might be from longman@redhat.com are
>
> mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
> ipc-mqueue-use-get_tree_nodev-in-mqueue_get_tree.patch
>
Sorry, this patch isn't complete. I will send out a v2 soon.
Thanks,
Longman
^ permalink raw reply [flat|nested] 5+ messages in thread
* + mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch added to -mm tree
@ 2022-03-31 21:54 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2022-03-31 21:54 UTC (permalink / raw)
To: mm-commits, mingo, kirill.shutemov, jforbes, aquini, longman, akpm
The patch titled
Subject: mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning
has been added to the -mm tree. Its filename is
mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Waiman Long <longman@redhat.com>
Subject: mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning
The gcc 12 compiler reports a "'mem_section' will never be NULL" warning
on the following code:
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
#ifdef CONFIG_SPARSEMEM_EXTREME
if (!mem_section)
return NULL;
#endif
if (!mem_section[SECTION_NR_TO_ROOT(nr)])
return NULL;
:
It happens with CONFIG_SPARSEMEM_EXTREME off. The mem_section definition
is
#ifdef CONFIG_SPARSEMEM_EXTREME
extern struct mem_section **mem_section;
#else
extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
#endif
In the !CONFIG_SPARSEMEM_EXTREME case, mem_section
is a static 2-dimensional array and so the check
"!mem_section[SECTION_NR_TO_ROOT(nr)]" doesn't make sense.
Fix this warning by moving the "!mem_section[SECTION_NR_TO_ROOT(nr)]"
check up inside the CONFIG_SPARSEMEM_EXTREME block and adding an explicit
NR_SECTION_ROOTS check to make sure that there is no out-of-bound array
access.
Link: https://lkml.kernel.org/r/20220331180246.2746210-1-longman@redhat.com
Fixes: 3e347261a80b ("sparsemem extreme implementation")
Signed-off-by: Waiman Long <longman@redhat.com>
Reported-by: Justin Forbes <jforbes@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/mmzone.h | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
--- a/include/linux/mmzone.h~mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning
+++ a/include/linux/mmzone.h
@@ -1397,13 +1397,16 @@ static inline unsigned long *section_to_
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
+ unsigned long root = SECTION_NR_TO_ROOT(nr);
+
+ if (unlikely(root >= NR_SECTION_ROOTS))
+ return NULL;
+
#ifdef CONFIG_SPARSEMEM_EXTREME
- if (!mem_section)
+ if (!mem_section || !mem_section[root])
return NULL;
#endif
- if (!mem_section[SECTION_NR_TO_ROOT(nr)])
- return NULL;
- return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
+ return &mem_section[root][nr & SECTION_ROOT_MASK];
}
extern size_t mem_section_usage_size(void);
_
Patches currently in -mm which might be from longman@redhat.com are
mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
mm-list_lru-fix-possible-race-in-memcg_reparent_list_lru_node.patch
ipc-mqueue-use-get_tree_nodev-in-mqueue_get_tree.patch
^ permalink raw reply [flat|nested] 5+ messages in thread
* + mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch added to -mm tree
@ 2022-03-31 21:53 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2022-03-31 21:53 UTC (permalink / raw)
To: mm-commits, mingo, kirill.shutemov, jforbes, aquini, longman, akpm
The patch titled
Subject: mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning
has been added to the -mm tree. Its filename is
mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Waiman Long <longman@redhat.com>
Subject: mm/sparsemem: fix 'mem_section' will never be NULL gcc 12 warning
The gcc 12 compiler reports a "'mem_section' will never be NULL" warning
on the following code:
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
#ifdef CONFIG_SPARSEMEM_EXTREME
if (!mem_section)
return NULL;
#endif
if (!mem_section[SECTION_NR_TO_ROOT(nr)])
return NULL;
:
It happens with CONFIG_SPARSEMEM_EXTREME off. The mem_section definition
is
#ifdef CONFIG_SPARSEMEM_EXTREME
extern struct mem_section **mem_section;
#else
extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
#endif
In the !CONFIG_SPARSEMEM_EXTREME case, mem_section
is a static 2-dimensional array and so the check
"!mem_section[SECTION_NR_TO_ROOT(nr)]" doesn't make sense.
Fix this warning by moving the "!mem_section[SECTION_NR_TO_ROOT(nr)]"
check up inside the CONFIG_SPARSEMEM_EXTREME block and adding an explicit
NR_SECTION_ROOTS check to make sure that there is no out-of-bound array
access.
Link: https://lkml.kernel.org/r/20220331180246.2746210-1-longman@redhat.com
Fixes: 3e347261a80b ("sparsemem extreme implementation")
Signed-off-by: Waiman Long <longman@redhat.com>
Reported-by: Justin Forbes <jforbes@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/mmzone.h | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
--- a/include/linux/mmzone.h~mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning
+++ a/include/linux/mmzone.h
@@ -1397,13 +1397,16 @@ static inline unsigned long *section_to_
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
+ unsigned long root = SECTION_NR_TO_ROOT(nr);
+
+ if (unlikely(root >= NR_SECTION_ROOTS))
+ return NULL;
+
#ifdef CONFIG_SPARSEMEM_EXTREME
- if (!mem_section)
+ if (!mem_section || !mem_section[root])
return NULL;
#endif
- if (!mem_section[SECTION_NR_TO_ROOT(nr)])
- return NULL;
- return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
+ return &mem_section[root][nr & SECTION_ROOT_MASK];
}
extern size_t mem_section_usage_size(void);
_
Patches currently in -mm which might be from longman@redhat.com are
mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
mm-list_lru-fix-possible-race-in-memcg_reparent_list_lru_node.patch
ipc-mqueue-use-get_tree_nodev-in-mqueue_get_tree.patch
^ permalink raw reply [flat|nested] 5+ messages in thread
* + mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch added to -mm tree
@ 2022-03-31 2:02 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2022-03-31 2:02 UTC (permalink / raw)
To: mm-commits, mingo, kirill.shutemov, jforbes, aquini, longman, akpm
The patch titled
Subject: mm/sparsemem: Fix 'mem_section' will never be NULL gcc 12 warning
has been added to the -mm tree. Its filename is
mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Waiman Long <longman@redhat.com>
Subject: mm/sparsemem: Fix 'mem_section' will never be NULL gcc 12 warning
The gcc 12 compiler reports a "'mem_section' will never be NULL"
warning on the following code:
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
#ifdef CONFIG_SPARSEMEM_EXTREME
if (!mem_section)
return NULL;
#endif
if (!mem_section[SECTION_NR_TO_ROOT(nr)])
return NULL;
:
It happens with CONFIG_SPARSEMEM_EXTREME off. The mem_section
definition is
#ifdef CONFIG_SPARSEMEM_EXTREME
extern struct mem_section **mem_section;
#else
extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
#endif
In the !CONFIG_SPARSEMEM_EXTREME case, mem_section
is a static 2-dimensional array and so the check
"!mem_section[SECTION_NR_TO_ROOT(nr)]" doesn't make sense.
Fix this warning by moving the "!mem_section[SECTION_NR_TO_ROOT(nr)]"
check up inside the CONFIG_SPARSEMEM_EXTREME block.
Link: https://lkml.kernel.org/r/20220330205919.2713275-1-longman@redhat.com
Fixes: 3e347261a80b ("sparsemem extreme implementation")
Signed-off-by: Waiman Long <longman@redhat.com>
Reported-by: Justin Forbes <jforbes@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/mmzone.h | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/include/linux/mmzone.h~mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning
+++ a/include/linux/mmzone.h
@@ -1398,11 +1398,9 @@ static inline unsigned long *section_to_
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
#ifdef CONFIG_SPARSEMEM_EXTREME
- if (!mem_section)
+ if (!mem_section || !mem_section[SECTION_NR_TO_ROOT(nr)])
return NULL;
#endif
- if (!mem_section[SECTION_NR_TO_ROOT(nr)])
- return NULL;
return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
}
extern size_t mem_section_usage_size(void);
_
Patches currently in -mm which might be from longman@redhat.com are
mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch
ipc-mqueue-use-get_tree_nodev-in-mqueue_get_tree.patch
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-03-31 21:54 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2022-02-01 19:34 + mm-sparsemem-fix-mem_section-will-never-be-null-gcc-12-warning.patch added to -mm tree Andrew Morton
2022-02-02 0:34 ` Waiman Long
2022-03-31 2:02 Andrew Morton
2022-03-31 21:53 Andrew Morton
2022-03-31 21:54 Andrew Morton
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