diff options
| -rw-r--r-- | mm/internal.h | 19 | ||||
| -rw-r--r-- | mm/util.c | 41 | ||||
| -rw-r--r-- | mm/vma.c | 26 | ||||
| -rw-r--r-- | tools/testing/vma/include/dup.h | 8 |
4 files changed, 40 insertions, 54 deletions
diff --git a/mm/internal.h b/mm/internal.h index 4dddd89153d4..241510e21f4b 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1863,6 +1863,25 @@ static inline int io_remap_pfn_range_prepare(struct vm_area_desc *desc) return 0; } +/* + * When we succeed an mmap action or just before we unmap a VMA on error, we + * need to ensure any rmap lock held is released. On unmap it's required to + * avoid a deadlock. + */ +static inline void maybe_rmap_unlock_action(struct vm_area_struct *vma, + struct mmap_action *action) +{ + struct file *file; + + if (!action->hide_from_rmap_until_complete) + return; + + VM_WARN_ON_ONCE(vma_is_anonymous(vma)); + file = vma->vm_file; + i_mmap_unlock_write(file->f_mapping); + action->hide_from_rmap_until_complete = false; +} + #ifdef CONFIG_MMU_NOTIFIER static inline bool clear_flush_young_ptes_notify(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, unsigned int nr) diff --git a/mm/util.c b/mm/util.c index 54eab29adb56..e272efca8c0e 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1219,13 +1219,7 @@ int compat_vma_mmap(struct file *file, struct vm_area_struct *vma) action->hide_from_rmap_until_complete = false; set_vma_from_desc(vma, &desc); - err = mmap_action_complete(vma, action); - if (err) { - const size_t len = vma_pages(vma) << PAGE_SHIFT; - - do_munmap(current->mm, vma->vm_start, len, NULL); - } - return err; + return mmap_action_complete(vma, action); } EXPORT_SYMBOL(compat_vma_mmap); @@ -1320,26 +1314,30 @@ again: static int mmap_action_finish(struct vm_area_struct *vma, struct mmap_action *action, int err) { + size_t len; + + if (!err && action->success_hook) + err = action->success_hook(vma); + + /* do_munmap() might take rmap lock, so release if held. */ + maybe_rmap_unlock_action(vma, action); + if (!err) + return 0; + /* * If an error occurs, unmap the VMA altogether and return an error. We * only clear the newly allocated VMA, since this function is only * invoked if we do NOT merge, so we only clean up the VMA we created. */ - if (err) { - if (action->error_hook) { - /* We may want to filter the error. */ - err = action->error_hook(err); - - /* The caller should not clear the error. */ - VM_WARN_ON_ONCE(!err); - } - return err; + len = vma_pages(vma) << PAGE_SHIFT; + do_munmap(current->mm, vma->vm_start, len, NULL); + if (action->error_hook) { + /* We may want to filter the error. */ + err = action->error_hook(err); + /* The caller should not clear the error. */ + VM_WARN_ON_ONCE(!err); } - - if (action->success_hook) - return action->success_hook(vma); - - return 0; + return err; } #ifdef CONFIG_MMU @@ -1377,7 +1375,6 @@ EXPORT_SYMBOL(mmap_action_prepare); */ int mmap_action_complete(struct vm_area_struct *vma, struct mmap_action *action) - { int err = 0; @@ -2729,30 +2729,6 @@ static bool can_set_ksm_flags_early(struct mmap_state *map) return false; } -static int call_action_complete(struct mmap_state *map, - struct mmap_action *action, - struct vm_area_struct *vma) -{ - int err; - - err = mmap_action_complete(vma, action); - - /* If we held the file rmap we need to release it. */ - if (action->hide_from_rmap_until_complete) { - struct file *file = vma->vm_file; - - i_mmap_unlock_write(file->f_mapping); - } - - if (err) { - const size_t len = vma_pages(vma) << PAGE_SHIFT; - - do_munmap(current->mm, vma->vm_start, len, NULL); - } - - return err; -} - static unsigned long __mmap_region(struct file *file, unsigned long addr, unsigned long len, vma_flags_t vma_flags, unsigned long pgoff, struct list_head *uf) @@ -2804,7 +2780,7 @@ static unsigned long __mmap_region(struct file *file, unsigned long addr, __mmap_complete(&map, vma); if (have_mmap_prepare && allocated_new) { - error = call_action_complete(&map, &desc.action, vma); + error = mmap_action_complete(vma, &desc.action); if (error) return error; diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/dup.h index 64bb56980b9c..a95a4b07f68b 100644 --- a/tools/testing/vma/include/dup.h +++ b/tools/testing/vma/include/dup.h @@ -1300,13 +1300,7 @@ static inline int compat_vma_mmap(struct file *file, struct vm_area_struct *vma) action->hide_from_rmap_until_complete = false; set_vma_from_desc(vma, &desc); - err = mmap_action_complete(vma, action); - if (err) { - const size_t len = vma_pages(vma) << PAGE_SHIFT; - - do_munmap(current->mm, vma->vm_start, len, NULL); - } - return err; + return mmap_action_complete(vma, action); } static inline void vma_iter_init(struct vma_iterator *vmi, |