* [PATCH] mm: make apply_to_page_range more robust
@ 2016-01-15 5:41 ` Mika Penttilä
0 siblings, 0 replies; 6+ messages in thread
From: Mika Penttilä @ 2016-01-15 5:41 UTC (permalink / raw)
To: LKML, linux-mm
Recent changes (4.4.0+) in module loader triggered oops on ARM. While
loading a module, size in :
apply_to_page_range(struct mm_struct *mm, unsigned long addr, unsigned
long size, pte_fn_t fn, void *data);
can be 0 triggering the bug BUG_ON(addr >= end);.
Fix by letting call with zero size succeed.
--Mika
Signed-off-by: mika.penttila@nextfour.com
---
diff --git a/mm/memory.c b/mm/memory.c
index c387430..c3d1a2e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1884,6 +1884,9 @@ int apply_to_page_range(struct mm_struct *mm,
unsigned long addr,
unsigned long end = addr + size;
int err;
+ if (!size)
+ return 0;
+
BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr);
do {
--
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^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] mm: make apply_to_page_range more robust
@ 2016-01-15 5:41 ` Mika Penttilä
0 siblings, 0 replies; 6+ messages in thread
From: Mika Penttilä @ 2016-01-15 5:41 UTC (permalink / raw)
To: LKML, linux-mm
Recent changes (4.4.0+) in module loader triggered oops on ARM. While
loading a module, size in :
apply_to_page_range(struct mm_struct *mm, unsigned long addr, unsigned
long size, pte_fn_t fn, void *data);
can be 0 triggering the bug BUG_ON(addr >= end);.
Fix by letting call with zero size succeed.
--Mika
Signed-off-by: mika.penttila@nextfour.com
---
diff --git a/mm/memory.c b/mm/memory.c
index c387430..c3d1a2e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1884,6 +1884,9 @@ int apply_to_page_range(struct mm_struct *mm,
unsigned long addr,
unsigned long end = addr + size;
int err;
+ if (!size)
+ return 0;
+
BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr);
do {
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] mm: make apply_to_page_range more robust
2016-01-15 5:41 ` Mika Penttilä
@ 2016-01-17 10:02 ` Pekka Enberg
-1 siblings, 0 replies; 6+ messages in thread
From: Pekka Enberg @ 2016-01-17 10:02 UTC (permalink / raw)
To: Mika Penttilä; +Cc: LKML, linux-mm@kvack.org, Andrew Morton
On Fri, Jan 15, 2016 at 7:41 AM, Mika Penttilä
<mika.penttila@nextfour.com> wrote:
> Recent changes (4.4.0+) in module loader triggered oops on ARM. While
> loading a module, size in :
>
> apply_to_page_range(struct mm_struct *mm, unsigned long addr, unsigned
> long size, pte_fn_t fn, void *data);
>
> can be 0 triggering the bug BUG_ON(addr >= end);.
>
> Fix by letting call with zero size succeed.
>
> --Mika
>
> Signed-off-by: mika.penttila@nextfour.com
Reviewed-by: Pekka Enberg <penberg@kernel.org>
We could also replace that BUG_ON() with a WARN_ON() and return -EINVAL.
> ---
>
> diff --git a/mm/memory.c b/mm/memory.c
> index c387430..c3d1a2e 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1884,6 +1884,9 @@ int apply_to_page_range(struct mm_struct *mm,
> unsigned long addr,
> unsigned long end = addr + size;
> int err;
>
> + if (!size)
> + return 0;
> +
> BUG_ON(addr >= end);
> pgd = pgd_offset(mm, addr);
> do {
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mm: make apply_to_page_range more robust
@ 2016-01-17 10:02 ` Pekka Enberg
0 siblings, 0 replies; 6+ messages in thread
From: Pekka Enberg @ 2016-01-17 10:02 UTC (permalink / raw)
To: Mika Penttilä; +Cc: LKML, linux-mm@kvack.org, Andrew Morton
On Fri, Jan 15, 2016 at 7:41 AM, Mika Penttilä
<mika.penttila@nextfour.com> wrote:
> Recent changes (4.4.0+) in module loader triggered oops on ARM. While
> loading a module, size in :
>
> apply_to_page_range(struct mm_struct *mm, unsigned long addr, unsigned
> long size, pte_fn_t fn, void *data);
>
> can be 0 triggering the bug BUG_ON(addr >= end);.
>
> Fix by letting call with zero size succeed.
>
> --Mika
>
> Signed-off-by: mika.penttila@nextfour.com
Reviewed-by: Pekka Enberg <penberg@kernel.org>
We could also replace that BUG_ON() with a WARN_ON() and return -EINVAL.
> ---
>
> diff --git a/mm/memory.c b/mm/memory.c
> index c387430..c3d1a2e 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1884,6 +1884,9 @@ int apply_to_page_range(struct mm_struct *mm,
> unsigned long addr,
> unsigned long end = addr + size;
> int err;
>
> + if (!size)
> + return 0;
> +
> BUG_ON(addr >= end);
> pgd = pgd_offset(mm, addr);
> do {
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm: make apply_to_page_range more robust
2016-01-15 5:41 ` Mika Penttilä
@ 2016-01-19 22:21 ` David Rientjes
-1 siblings, 0 replies; 6+ messages in thread
From: David Rientjes @ 2016-01-19 22:21 UTC (permalink / raw)
To: Mika Penttilä; +Cc: LKML, linux-mm
[-- Attachment #1: Type: TEXT/PLAIN, Size: 1137 bytes --]
On Fri, 15 Jan 2016, Mika PenttilA? wrote:
> Recent changes (4.4.0+) in module loader triggered oops on ARM. While
> loading a module, size in :
>
> apply_to_page_range(struct mm_struct *mm, unsigned long addr, unsigned
> long size, pte_fn_t fn, void *data);
>
> can be 0 triggering the bug BUG_ON(addr >= end);.
>
> Fix by letting call with zero size succeed.
>
> --Mika
>
> Signed-off-by: mika.penttila@nextfour.com
> ---
>
> diff --git a/mm/memory.c b/mm/memory.c
> index c387430..c3d1a2e 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1884,6 +1884,9 @@ int apply_to_page_range(struct mm_struct *mm,
> unsigned long addr,
> unsigned long end = addr + size;
> int err;
>
> + if (!size)
> + return 0;
> +
> BUG_ON(addr >= end);
> pgd = pgd_offset(mm, addr);
> do {
What is calling apply_to_page_range() with size == 0? I'm not sure we
should be adding "robust"ness here and that size == 0 is actually an
indication of a bug somewhere else that we want to know about.
Btw, your patch is line-wrapped and your sign-off-line doesn't include
your full name.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mm: make apply_to_page_range more robust
@ 2016-01-19 22:21 ` David Rientjes
0 siblings, 0 replies; 6+ messages in thread
From: David Rientjes @ 2016-01-19 22:21 UTC (permalink / raw)
To: Mika Penttilä; +Cc: LKML, linux-mm
[-- Attachment #1: Type: TEXT/PLAIN, Size: 1137 bytes --]
On Fri, 15 Jan 2016, Mika Penttilä wrote:
> Recent changes (4.4.0+) in module loader triggered oops on ARM. While
> loading a module, size in :
>
> apply_to_page_range(struct mm_struct *mm, unsigned long addr, unsigned
> long size, pte_fn_t fn, void *data);
>
> can be 0 triggering the bug BUG_ON(addr >= end);.
>
> Fix by letting call with zero size succeed.
>
> --Mika
>
> Signed-off-by: mika.penttila@nextfour.com
> ---
>
> diff --git a/mm/memory.c b/mm/memory.c
> index c387430..c3d1a2e 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1884,6 +1884,9 @@ int apply_to_page_range(struct mm_struct *mm,
> unsigned long addr,
> unsigned long end = addr + size;
> int err;
>
> + if (!size)
> + return 0;
> +
> BUG_ON(addr >= end);
> pgd = pgd_offset(mm, addr);
> do {
What is calling apply_to_page_range() with size == 0? I'm not sure we
should be adding "robust"ness here and that size == 0 is actually an
indication of a bug somewhere else that we want to know about.
Btw, your patch is line-wrapped and your sign-off-line doesn't include
your full name.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-01-19 22:21 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-01-15 5:41 [PATCH] mm: make apply_to_page_range more robust Mika Penttilä
2016-01-15 5:41 ` Mika Penttilä
2016-01-17 10:02 ` Pekka Enberg
2016-01-17 10:02 ` Pekka Enberg
2016-01-19 22:21 ` David Rientjes
2016-01-19 22:21 ` David Rientjes
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