diff options
| author | David S. Miller <davem@davemloft.net> | 2014-08-04 16:34:01 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-09-13 23:41:50 +0100 |
| commit | 0d675523fae75f7435886bc7601ef7caed2446aa (patch) | |
| tree | 1e24ed83ed21886709488739445e62c7b6e5d1d6 | |
| parent | 47fbb3be6dfb86d6cf27b68f660115a4e6694c4d (diff) | |
sparc64: Do not insert non-valid PTEs into the TSB hash table.
[ 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@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | arch/sparc/mm/init_64.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index b4989f9aed30..77ad81510a23 100644 --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -309,6 +309,10 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t * tsb_index = MM_TSB_BASE; tsb_hash_shift = PAGE_SHIFT; + /* Don't insert a non-valid PTE into the TSB, we'll deadlock. */ + if (!(pte_val(pte) & _PAGE_VALID)) + return; + spin_lock_irqsave(&mm->context.lock, flags); #ifdef CONFIG_HUGETLB_PAGE |