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Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c36
1 files changed, 20 insertions, 16 deletions
diff --git a/mm/memory.c b/mm/memory.c
index e158f7ac6730..fe2fba27ded2 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -68,6 +68,7 @@
#include <linux/debugfs.h>
#include <linux/userfaultfd_k.h>
#include <linux/dax.h>
+#include <linux/oom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
@@ -2893,6 +2894,7 @@ static int do_anonymous_page(struct vm_fault *vmf)
struct vm_area_struct *vma = vmf->vma;
struct mem_cgroup *memcg;
struct page *page;
+ int ret = 0;
pte_t entry;
/* File mapping without ->vm_ops ? */
@@ -2925,6 +2927,9 @@ static int do_anonymous_page(struct vm_fault *vmf)
vmf->address, &vmf->ptl);
if (!pte_none(*vmf->pte))
goto unlock;
+ ret = check_stable_address_space(vma->vm_mm);
+ if (ret)
+ goto unlock;
/* Deliver the page fault to userland, check inside PT lock */
if (userfaultfd_missing(vma)) {
pte_unmap_unlock(vmf->pte, vmf->ptl);
@@ -2959,6 +2964,10 @@ static int do_anonymous_page(struct vm_fault *vmf)
if (!pte_none(*vmf->pte))
goto release;
+ ret = check_stable_address_space(vma->vm_mm);
+ if (ret)
+ goto release;
+
/* Deliver the page fault to userland, check inside PT lock */
if (userfaultfd_missing(vma)) {
pte_unmap_unlock(vmf->pte, vmf->ptl);
@@ -2978,7 +2987,7 @@ setpte:
update_mmu_cache(vma, vmf->address, vmf->pte);
unlock:
pte_unmap_unlock(vmf->pte, vmf->ptl);
- return 0;
+ return ret;
release:
mem_cgroup_cancel_charge(page, memcg, false);
put_page(page);
@@ -3252,7 +3261,7 @@ int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
int finish_fault(struct vm_fault *vmf)
{
struct page *page;
- int ret;
+ int ret = 0;
/* Did we COW the page? */
if ((vmf->flags & FAULT_FLAG_WRITE) &&
@@ -3260,7 +3269,15 @@ int finish_fault(struct vm_fault *vmf)
page = vmf->cow_page;
else
page = vmf->page;
- ret = alloc_set_pte(vmf, vmf->memcg, page);
+
+ /*
+ * check even for read faults because we might have lost our CoWed
+ * page
+ */
+ if (!(vmf->vma->vm_flags & VM_SHARED))
+ ret = check_stable_address_space(vmf->vma->vm_mm);
+ if (!ret)
+ ret = alloc_set_pte(vmf, vmf->memcg, page);
if (vmf->pte)
pte_unmap_unlock(vmf->pte, vmf->ptl);
return ret;
@@ -3900,19 +3917,6 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
mem_cgroup_oom_synchronize(false);
}
- /*
- * This mm has been already reaped by the oom reaper and so the
- * refault cannot be trusted in general. Anonymous refaults would
- * lose data and give a zero page instead e.g. This is especially
- * problem for use_mm() because regular tasks will just die and
- * the corrupted data will not be visible anywhere while kthread
- * will outlive the oom victim and potentially propagate the date
- * further.
- */
- if (unlikely((current->flags & PF_KTHREAD) && !(ret & VM_FAULT_ERROR)
- && test_bit(MMF_UNSTABLE, &vma->vm_mm->flags)))
- ret = VM_FAULT_SIGBUS;
-
return ret;
}
EXPORT_SYMBOL_GPL(handle_mm_fault);