[PATCH 3.10 19/24] sparc64: Do not insert non-valid PTEs into the TSB hash table.
From: Greg Kroah-Hartman
Date: Fri Aug 08 2014 - 18:06:45 EST
3.10-stable review patch. If anyone has any objections, please let me know.
From: "David S. Miller" <davem@xxxxxxxxxxxxx>
[ Upstream commit 18f38132528c3e603c66ea464727b29e9bbcb91b ]
The assumption was that update_mmu_cache() (and the equivalent for PMDs) would
only be called when the PTE being installed will be accessible by the user.
This is not true for code paths originating from remove_migration_pte().
There are dire consequences for placing a non-valid PTE into the TSB. The TLB
miss frramework assumes thatwhen a TSB entry matches we can just load it into
the TLB and return from the TLB miss trap.
So if a non-valid PTE is in there, we will deadlock taking the TLB miss over
and over, never satisfying the miss.
Just exit early from update_mmu_cache() and friends in this situation.
Based upon a report and patch from Christopher Alexander Tobias Schulze.
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
arch/sparc/mm/init_64.c | 4 ++++
1 file changed, 4 insertions(+)
@@ -350,6 +350,10 @@ void update_mmu_cache(struct vm_area_str
mm = vma->vm_mm;
+ /* Don't insert a non-valid PTE into the TSB, we'll deadlock. */
+ if (!pte_accessible(mm, pte))
#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
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