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authorAndrea Arcangeli <aarcange@redhat.com>2011-02-16 15:45:22 -0800
committerIngo Molnar <mingo@elte.hu>2011-03-10 09:41:57 +0100
commita79e53d85683c6dd9f99c90511028adc2043031f (patch)
tree191f423331b608a5f7f134f484ce62a9ee7fb4a6 /arch/x86/mm/pgtable.c
parentf86268549f424f83b9eb0963989270e14fbfc3de (diff)
downloadop-kernel-dev-a79e53d85683c6dd9f99c90511028adc2043031f.zip
op-kernel-dev-a79e53d85683c6dd9f99c90511028adc2043031f.tar.gz
x86/mm: Fix pgd_lock deadlock
It's forbidden to take the page_table_lock with the irq disabled or if there's contention the IPIs (for tlb flushes) sent with the page_table_lock held will never run leading to a deadlock. Nobody takes the pgd_lock from irq context so the _irqsave can be removed. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@kernel.org> LKML-Reference: <201102162345.p1GNjMjm021738@imap1.linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/mm/pgtable.c')
-rw-r--r--arch/x86/mm/pgtable.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 500242d..0113d19 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -121,14 +121,12 @@ static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
static void pgd_dtor(pgd_t *pgd)
{
- unsigned long flags; /* can be called from interrupt context */
-
if (SHARED_KERNEL_PMD)
return;
- spin_lock_irqsave(&pgd_lock, flags);
+ spin_lock(&pgd_lock);
pgd_list_del(pgd);
- spin_unlock_irqrestore(&pgd_lock, flags);
+ spin_unlock(&pgd_lock);
}
/*
@@ -260,7 +258,6 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd;
pmd_t *pmds[PREALLOCATED_PMDS];
- unsigned long flags;
pgd = (pgd_t *)__get_free_page(PGALLOC_GFP);
@@ -280,12 +277,12 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
* respect to anything walking the pgd_list, so that they
* never see a partially populated pgd.
*/
- spin_lock_irqsave(&pgd_lock, flags);
+ spin_lock(&pgd_lock);
pgd_ctor(mm, pgd);
pgd_prepopulate_pmd(mm, pgd, pmds);
- spin_unlock_irqrestore(&pgd_lock, flags);
+ spin_unlock(&pgd_lock);
return pgd;
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