diff options
author | David S. Miller <davem@davemloft.net> | 2014-08-05 01:34:01 +0200 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2014-08-05 01:34:01 +0200 |
commit | 18f38132528c3e603c66ea464727b29e9bbcb91b (patch) | |
tree | 9600ee863f2b3fc4898ad218a1273cf77fe020d7 /arch/sparc | |
parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 (diff) | |
download | linux-18f38132528c3e603c66ea464727b29e9bbcb91b.tar.xz linux-18f38132528c3e603c66ea464727b29e9bbcb91b.zip |
sparc64: Do not insert non-valid PTEs into the TSB hash table.
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>
Diffstat (limited to 'arch/sparc')
-rw-r--r-- | arch/sparc/mm/init_64.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index 16b58ff11e65..db5ddde0b335 100644 --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -351,6 +351,10 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t * mm = vma->vm_mm; + /* Don't insert a non-valid PTE into the TSB, we'll deadlock. */ + if (!pte_accessible(mm, pte)) + return; + spin_lock_irqsave(&mm->context.lock, flags); #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) @@ -2619,6 +2623,10 @@ void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr, pte = pmd_val(entry); + /* Don't insert a non-valid PMD into the TSB, we'll deadlock. */ + if (!(pte & _PAGE_VALID)) + return; + /* We are fabricating 8MB pages using 4MB real hw pages. */ pte |= (addr & (1UL << REAL_HPAGE_SHIFT)); |