This is a note to let you know that I've just added the patch titled
powerpc: Fix __get_user_pages_fast() irq handling
to the 3.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-fix-__get_user_pages_fast-irq-handling.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 95f715b08fa4a953771398d20cbe35a6803ea41d Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Date: Thu, 14 Nov 2013 15:01:43 +1100
Subject: powerpc: Fix __get_user_pages_fast() irq handling
From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
commit 95f715b08fa4a953771398d20cbe35a6803ea41d upstream.
__get_user_pages_fast() may be called with interrupts disabled (see e.g.
get_futex_key() in kernel/futex.c) and therefore should use local_irq_save()
and local_irq_restore() instead of local_irq_disable()/enable().
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/mm/gup.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c
@@ -123,6 +123,7 @@ int __get_user_pages_fast(unsigned long
struct mm_struct *mm = current->mm;
unsigned long addr, len, end;
unsigned long next;
+ unsigned long flags;
pgd_t *pgdp;
int nr = 0;
@@ -156,7 +157,7 @@ int __get_user_pages_fast(unsigned long
* So long as we atomically load page table pointers versus teardown,
* we can follow the address down to the the page and take a ref on it.
*/
- local_irq_disable();
+ local_irq_save(flags);
pgdp = pgd_offset(mm, addr);
do {
@@ -179,7 +180,7 @@ int __get_user_pages_fast(unsigned long
break;
} while (pgdp++, addr = next, addr != end);
- local_irq_enable();
+ local_irq_restore(flags);
return nr;
}
Patches currently in stable-queue which might be from heiko.carstens@xxxxxxxxxx are
queue-3.12/powerpc-fix-__get_user_pages_fast-irq-handling.patch
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