diff options
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 46 |
1 files changed, 36 insertions, 10 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index f19efcf75418..4c5981651407 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -44,6 +44,7 @@ #include <linux/userfaultfd_k.h> #include <linux/moduleparam.h> #include <linux/pkeys.h> +#include <linux/oom.h> #include <linux/uaccess.h> #include <asm/cacheflush.h> @@ -2639,13 +2640,6 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, if (vma->vm_start >= end) return 0; - if (uf) { - int error = userfaultfd_unmap_prep(vma, start, end, uf); - - if (error) - return error; - } - /* * If we need to split any vma, do it now to save pain later. * @@ -2679,6 +2673,21 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, } vma = prev ? prev->vm_next : mm->mmap; + if (unlikely(uf)) { + /* + * If userfaultfd_unmap_prep returns an error the vmas + * will remain splitted, but userland will get a + * highly unexpected error anyway. This is no + * different than the case where the first of the two + * __split_vma fails, but we don't undo the first + * split, despite we could. This is unlikely enough + * failure that it's not worth optimizing it for. + */ + int error = userfaultfd_unmap_prep(vma, start, end, uf); + if (error) + return error; + } + /* * unlock any mlock()ed ranges before detaching vmas */ @@ -2993,6 +3002,23 @@ void exit_mmap(struct mm_struct *mm) /* Use -1 here to ensure all VMAs in the mm are unmapped */ unmap_vmas(&tlb, vma, 0, -1); + set_bit(MMF_OOM_SKIP, &mm->flags); + if (unlikely(tsk_is_oom_victim(current))) { + /* + * Wait for oom_reap_task() to stop working on this + * mm. Because MMF_OOM_SKIP is already set before + * calling down_read(), oom_reap_task() will not run + * on this "mm" post up_write(). + * + * tsk_is_oom_victim() cannot be set from under us + * either because current->mm is already set to NULL + * under task_lock before calling mmput and oom_mm is + * set not NULL by the OOM killer only if current->mm + * is found not NULL while holding the task_lock. + */ + down_write(&mm->mmap_sem); + up_write(&mm->mmap_sem); + } free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING); tlb_finish_mmu(&tlb, 0, -1); @@ -3514,7 +3540,7 @@ static int init_user_reserve(void) { unsigned long free_kbytes; - free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); return 0; @@ -3535,7 +3561,7 @@ static int init_admin_reserve(void) { unsigned long free_kbytes; - free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); return 0; @@ -3579,7 +3605,7 @@ static int reserve_mem_notifier(struct notifier_block *nb, break; case MEM_OFFLINE: - free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); if (sysctl_user_reserve_kbytes > free_kbytes) { init_user_reserve(); |