Attachment 4334 Details for Bug 26661

[patch] 686-bigmem VM deadlock

93_26661_x86-mm-Fix-pgd_lock-deadlock.patch (text/plain), 6.79 KB, created by Philipp Hahn on 2012-04-19 08:57 CEST

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Creator: Philipp Hahn

Created: 2012-04-19 08:57 CEST

Size: 6.79 KB

patch

obsolete

>Bug #26661: 686-bigmem VM deadlock
>--- /dev/null
>+++ linux-2.6.32-2.6.32/debian/patches/bugfix/x86/x86-mm-Fix-pgd_lock-deadlock.patch
>@@ -0,0 +1,217 @@
>+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>
>+Git-commit: a79e53d85683c6dd9f99c90511028adc2043031f
>+--- a/arch/x86/mm/fault.c
>++++ b/arch/x86/mm/fault.c
>+@@ -223,15 +223,14 @@ void vmalloc_sync_all(void)
>+ 	     address >= TASK_SIZE && address < FIXADDR_TOP;
>+ 	     address += PMD_SIZE) {
>+ 
>+-		unsigned long flags;
>+ 		struct page *page;
>+ 
>+-		spin_lock_irqsave(&pgd_lock, flags);
>++		spin_lock(&pgd_lock);
>+ 		list_for_each_entry(page, &pgd_list, lru) {
>+ 			if (!vmalloc_sync_one(page_address(page), address))
>+ 				break;
>+ 		}
>+-		spin_unlock_irqrestore(&pgd_lock, flags);
>++		spin_unlock(&pgd_lock);
>+ 	}
>+ }
>+ 
>+@@ -331,13 +330,12 @@ void vmalloc_sync_all(void)
>+ 	     address += PGDIR_SIZE) {
>+ 
>+ 		const pgd_t *pgd_ref = pgd_offset_k(address);
>+-		unsigned long flags;
>+ 		struct page *page;
>+ 
>+ 		if (pgd_none(*pgd_ref))
>+ 			continue;
>+ 
>+-		spin_lock_irqsave(&pgd_lock, flags);
>++		spin_lock(&pgd_lock);
>+ 		list_for_each_entry(page, &pgd_list, lru) {
>+ 			pgd_t *pgd;
>+ 			pgd = (pgd_t *)page_address(page) + pgd_index(address);
>+@@ -346,7 +344,7 @@ void vmalloc_sync_all(void)
>+ 			else
>+ 				BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
>+ 		}
>+-		spin_unlock_irqrestore(&pgd_lock, flags);
>++		spin_unlock(&pgd_lock);
>+ 	}
>+ }
>+ 
>+--- a/arch/x86/mm/pageattr.c
>++++ b/arch/x86/mm/pageattr.c
>+@@ -56,12 +56,10 @@ static unsigned long direct_pages_count[
>+ 
>+ void update_page_count(int level, unsigned long pages)
>+ {
>+-	unsigned long flags;
>+-
>+ 	/* Protect against CPA */
>+-	spin_lock_irqsave(&pgd_lock, flags);
>++	spin_lock(&pgd_lock);
>+ 	direct_pages_count[level] += pages;
>+-	spin_unlock_irqrestore(&pgd_lock, flags);
>++	spin_unlock(&pgd_lock);
>+ }
>+ 
>+ static void split_page_count(int level)
>+@@ -354,7 +352,7 @@ static int
>+ try_preserve_large_page(pte_t *kpte, unsigned long address,
>+ 			struct cpa_data *cpa)
>+ {
>+-	unsigned long nextpage_addr, numpages, pmask, psize, flags, addr, pfn;
>++	unsigned long nextpage_addr, numpages, pmask, psize, addr, pfn;
>+ 	pte_t new_pte, old_pte, *tmp;
>+ 	pgprot_t old_prot, new_prot;
>+ 	int i, do_split = 1;
>+@@ -363,7 +361,7 @@ try_preserve_large_page(pte_t *kpte, uns
>+ 	if (cpa->force_split)
>+ 		return 1;
>+ 
>+-	spin_lock_irqsave(&pgd_lock, flags);
>++	spin_lock(&pgd_lock);
>+ 	/*
>+ 	 * Check for races, another CPU might have split this page
>+ 	 * up already:
>+@@ -458,14 +456,14 @@ try_preserve_large_page(pte_t *kpte, uns
>+ 	}
>+ 
>+ out_unlock:
>+-	spin_unlock_irqrestore(&pgd_lock, flags);
>++	spin_unlock(&pgd_lock);
>+ 
>+ 	return do_split;
>+ }
>+ 
>+ static int split_large_page(pte_t *kpte, unsigned long address)
>+ {
>+-	unsigned long flags, pfn, pfninc = 1;
>++	unsigned long pfn, pfninc = 1;
>+ 	unsigned int i, level;
>+ 	pte_t *pbase, *tmp;
>+ 	pgprot_t ref_prot;
>+@@ -479,7 +477,7 @@ static int split_large_page(pte_t *kpte,
>+ 	if (!base)
>+ 		return -ENOMEM;
>+ 
>+-	spin_lock_irqsave(&pgd_lock, flags);
>++	spin_lock(&pgd_lock);
>+ 	/*
>+ 	 * Check for races, another CPU might have split this page
>+ 	 * up for us already:
>+@@ -551,7 +549,7 @@ out_unlock:
>+ 	 */
>+ 	if (base)
>+ 		__free_page(base);
>+-	spin_unlock_irqrestore(&pgd_lock, flags);
>++	spin_unlock(&pgd_lock);
>+ 
>+ 	return 0;
>+ }
>+--- a/arch/x86/mm/pgtable.c
>++++ b/arch/x86/mm/pgtable.c
>+@@ -110,14 +110,12 @@ static void pgd_ctor(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);
>+ }
>+ 
>+ /*
>+@@ -248,7 +246,6 @@ 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);
>+ 
>+@@ -268,12 +265,12 @@ 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(pgd);
>+ 	pgd_prepopulate_pmd(mm, pgd, pmds);
>+ 
>+-	spin_unlock_irqrestore(&pgd_lock, flags);
>++	spin_unlock(&pgd_lock);
>+ 
>+ 	return pgd;
>+ 
>+--- a/arch/x86/xen/mmu.c
>++++ b/arch/x86/xen/mmu.c
>+@@ -988,10 +988,9 @@ static void xen_pgd_pin(struct mm_struct
>+  */
>+ void xen_mm_pin_all(void)
>+ {
>+-	unsigned long flags;
>+ 	struct page *page;
>+ 
>+-	spin_lock_irqsave(&pgd_lock, flags);
>++	spin_lock(&pgd_lock);
>+ 
>+ 	list_for_each_entry(page, &pgd_list, lru) {
>+ 		if (!PagePinned(page)) {
>+@@ -1000,7 +999,7 @@ void xen_mm_pin_all(void)
>+ 		}
>+ 	}
>+ 
>+-	spin_unlock_irqrestore(&pgd_lock, flags);
>++	spin_unlock(&pgd_lock);
>+ }
>+ 
>+ /*
>+@@ -1101,10 +1100,9 @@ static void xen_pgd_unpin(struct mm_stru
>+  */
>+ void xen_mm_unpin_all(void)
>+ {
>+-	unsigned long flags;
>+ 	struct page *page;
>+ 
>+-	spin_lock_irqsave(&pgd_lock, flags);
>++	spin_lock(&pgd_lock);
>+ 
>+ 	list_for_each_entry(page, &pgd_list, lru) {
>+ 		if (PageSavePinned(page)) {
>+@@ -1114,7 +1112,7 @@ void xen_mm_unpin_all(void)
>+ 		}
>+ 	}
>+ 
>+-	spin_unlock_irqrestore(&pgd_lock, flags);
>++	spin_unlock(&pgd_lock);
>+ }
>+ 
>+ void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
>--- linux-2.6.32-2.6.32/debian/patches/series/37-extra
>+++ linux-2.6.32-2.6.32/debian/patches/series/37-extra
>@@ -12,6 +12,7 @@
> + features/all/vserver/vs2.3.0.36.29.7.patch featureset=vserver
> + features/all/vserver/vserver-complete-fix-for-CVE-2010-4243.patch featureset=vserver
> 
>+- bugfix/x86/x86-mm-Fix-pgd_lock-deadlock.patch featureset=xen
> + features/all/xen/pvops.patch featureset=xen
> + features/all/xen/xen-netfront-make-smartpoll-optional-and-default-off.patch featureset=xen
> + features/all/xen/xen-grant-table-do-not-truncate-machine-address-on-g.patch featureset=xen
>--- linux-2.6.32-2.6.32/debian/patches/series/38
>+++ linux-2.6.32-2.6.32/debian/patches/series/38
>@@ -5,3 +5,5 @@
> + bugfix/x86/92_23258_kvm-clock-reset.patch
> + bugfix/x86/92_5f4e3f882731c65b5d64a2ff743fda96eaebb9ee.patch
> + bugfix/x86/92_7c4c0f4fd5c3e82234c0ab61c7e7ffdb8f3af07b.patch
>+
>++ bugfix/x86/x86-mm-Fix-pgd_lock-deadlock.patch

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