Replace vma_start_write() with vma_start_write_killable() when process_vma_walk_lock() is used with PGWALK_WRLOCK option. Adjust its direct and indirect users to check for a possible error and handle it. Ensure users handle EINTR correctly and do not ignore it. Suggested-by: Matthew Wilcox Signed-off-by: Suren Baghdasaryan --- fs/proc/task_mmu.c | 12 ++++++------ mm/mempolicy.c | 1 + mm/pagewalk.c | 22 +++++++++++++++------- 3 files changed, 22 insertions(+), 13 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index e091931d7ca1..33e5094a7842 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1774,15 +1774,15 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, struct vm_area_struct *vma; enum clear_refs_types type; int itype; - int rv; + int err; if (count > sizeof(buffer) - 1) count = sizeof(buffer) - 1; if (copy_from_user(buffer, buf, count)) return -EFAULT; - rv = kstrtoint(strstrip(buffer), 10, &itype); - if (rv < 0) - return rv; + err = kstrtoint(strstrip(buffer), 10, &itype); + if (err) + return err; type = (enum clear_refs_types)itype; if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST) return -EINVAL; @@ -1824,7 +1824,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, 0, mm, 0, -1UL); mmu_notifier_invalidate_range_start(&range); } - walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp); + err = walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp); if (type == CLEAR_REFS_SOFT_DIRTY) { mmu_notifier_invalidate_range_end(&range); flush_tlb_mm(mm); @@ -1837,7 +1837,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, } put_task_struct(task); - return count; + return err ? : count; } const struct file_operations proc_clear_refs_operations = { diff --git a/mm/mempolicy.c b/mm/mempolicy.c index c38a90487531..336753a4b2b2 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -969,6 +969,7 @@ static const struct mm_walk_ops queue_pages_lock_vma_walk_ops = { * (a hugetlbfs page or a transparent huge page being counted as 1). * -EIO - a misplaced page found, when MPOL_MF_STRICT specified without MOVEs. * -EFAULT - a hole in the memory range, when MPOL_MF_DISCONTIG_OK unspecified. + * -EINTR - walk got terminated due to pending fatal signal. */ static long queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end, diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 3ae2586ff45b..eca7bc711617 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -443,14 +443,13 @@ static inline void process_mm_walk_lock(struct mm_struct *mm, mmap_assert_write_locked(mm); } -static inline void process_vma_walk_lock(struct vm_area_struct *vma, - enum page_walk_lock walk_lock) +static int process_vma_walk_lock(struct vm_area_struct *vma, + enum page_walk_lock walk_lock) { #ifdef CONFIG_PER_VMA_LOCK switch (walk_lock) { case PGWALK_WRLOCK: - vma_start_write(vma); - break; + return vma_start_write_killable(vma); case PGWALK_WRLOCK_VERIFY: vma_assert_write_locked(vma); break; @@ -462,6 +461,7 @@ static inline void process_vma_walk_lock(struct vm_area_struct *vma, break; } #endif + return 0; } /* @@ -505,7 +505,9 @@ int walk_page_range_mm_unsafe(struct mm_struct *mm, unsigned long start, if (ops->pte_hole) err = ops->pte_hole(start, next, -1, &walk); } else { /* inside vma */ - process_vma_walk_lock(vma, ops->walk_lock); + err = process_vma_walk_lock(vma, ops->walk_lock); + if (err) + break; walk.vma = vma; next = min(end, vma->vm_end); vma = find_vma(mm, vma->vm_end); @@ -722,6 +724,7 @@ int walk_page_range_vma_unsafe(struct vm_area_struct *vma, unsigned long start, .vma = vma, .private = private, }; + int err; if (start >= end || !walk.mm) return -EINVAL; @@ -729,7 +732,9 @@ int walk_page_range_vma_unsafe(struct vm_area_struct *vma, unsigned long start, return -EINVAL; process_mm_walk_lock(walk.mm, ops->walk_lock); - process_vma_walk_lock(vma, ops->walk_lock); + err = process_vma_walk_lock(vma, ops->walk_lock); + if (err) + return err; return __walk_page_range(start, end, &walk); } @@ -752,6 +757,7 @@ int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops, .vma = vma, .private = private, }; + int err; if (!walk.mm) return -EINVAL; @@ -759,7 +765,9 @@ int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops, return -EINVAL; process_mm_walk_lock(walk.mm, ops->walk_lock); - process_vma_walk_lock(vma, ops->walk_lock); + err = process_vma_walk_lock(vma, ops->walk_lock); + if (err) + return err; return __walk_page_range(vma->vm_start, vma->vm_end, &walk); } -- 2.53.0.1018.g2bb0e51243-goog