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> --- I committed this to the sparc GIT tree and will queue this up for -stable. arch/sparc/mm/init_64.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index 16b58ff..db5ddde 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)); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
