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-rw-r--r--include/linux/userfaultfd_k.h2
-rw-r--r--mm/hugetlb.c6
-rw-r--r--mm/mempolicy.c2
-rw-r--r--mm/mprotect.c63
-rw-r--r--mm/userfaultfd.c16
5 files changed, 59 insertions, 30 deletions
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 9df0b9a762cc..3767f18114ef 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -73,7 +73,7 @@ extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start,
extern int mwriteprotect_range(struct mm_struct *dst_mm,
unsigned long start, unsigned long len,
bool enable_wp, atomic_t *mmap_changing);
-extern void uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *vma,
+extern long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *vma,
unsigned long start, unsigned long len, bool enable_wp);
/* mm helpers */
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a0d6d0980064..6fe65f14d33b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6660,8 +6660,10 @@ long hugetlb_change_protection(struct vm_area_struct *vma,
* pre-allocations to install pte markers.
*/
ptep = huge_pte_alloc(mm, vma, address, psize);
- if (!ptep)
+ if (!ptep) {
+ pages = -ENOMEM;
break;
+ }
}
ptl = huge_pte_lock(h, mm, ptep);
if (huge_pmd_unshare(mm, vma, address, ptep)) {
@@ -6751,7 +6753,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma,
hugetlb_vma_unlock_write(vma);
mmu_notifier_invalidate_range_end(&range);
- return pages << h->order;
+ return pages > 0 ? (pages << h->order) : pages;
}
/* Return true if reservation was successful, false otherwise. */
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index a86b8f15e2f0..85a34f1f3ab8 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -636,7 +636,7 @@ unsigned long change_prot_numa(struct vm_area_struct *vma,
tlb_gather_mmu(&tlb, vma->vm_mm);
nr_updated = change_protection(&tlb, vma, addr, end, MM_CP_PROT_NUMA);
- if (nr_updated)
+ if (nr_updated > 0)
count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
tlb_finish_mmu(&tlb);
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 0af22ab59ea8..92fc6f3fa512 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -330,28 +330,34 @@ uffd_wp_protect_file(struct vm_area_struct *vma, unsigned long cp_flags)
/*
* If wr-protecting the range for file-backed, populate pgtable for the case
* when pgtable is empty but page cache exists. When {pte|pmd|...}_alloc()
- * failed it means no memory, we don't have a better option but stop.
+ * failed we treat it the same way as pgtable allocation failures during
+ * page faults by kicking OOM and returning error.
*/
#define change_pmd_prepare(vma, pmd, cp_flags) \
- do { \
+ ({ \
+ long err = 0; \
if (unlikely(uffd_wp_protect_file(vma, cp_flags))) { \
- if (WARN_ON_ONCE(pte_alloc(vma->vm_mm, pmd))) \
- break; \
+ if (pte_alloc(vma->vm_mm, pmd)) \
+ err = -ENOMEM; \
} \
- } while (0)
+ err; \
+ })
+
/*
* This is the general pud/p4d/pgd version of change_pmd_prepare(). We need to
* have separate change_pmd_prepare() because pte_alloc() returns 0 on success,
* while {pmd|pud|p4d}_alloc() returns the valid pointer on success.
*/
#define change_prepare(vma, high, low, addr, cp_flags) \
- do { \
+ ({ \
+ long err = 0; \
if (unlikely(uffd_wp_protect_file(vma, cp_flags))) { \
low##_t *p = low##_alloc(vma->vm_mm, high, addr); \
- if (WARN_ON_ONCE(p == NULL)) \
- break; \
+ if (p == NULL) \
+ err = -ENOMEM; \
} \
- } while (0)
+ err; \
+ })
static inline long change_pmd_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pud_t *pud, unsigned long addr,
@@ -367,11 +373,15 @@ static inline long change_pmd_range(struct mmu_gather *tlb,
pmd = pmd_offset(pud, addr);
do {
- long this_pages;
+ long ret;
next = pmd_addr_end(addr, end);
- change_pmd_prepare(vma, pmd, cp_flags);
+ ret = change_pmd_prepare(vma, pmd, cp_flags);
+ if (ret) {
+ pages = ret;
+ break;
+ }
/*
* Automatic NUMA balancing walks the tables with mmap_lock
* held for read. It's possible a parallel update to occur
@@ -401,7 +411,11 @@ static inline long change_pmd_range(struct mmu_gather *tlb,
* cleared; make sure pmd populated if
* necessary, then fall-through to pte level.
*/
- change_pmd_prepare(vma, pmd, cp_flags);
+ ret = change_pmd_prepare(vma, pmd, cp_flags);
+ if (ret) {
+ pages = ret;
+ break;
+ }
} else {
/*
* change_huge_pmd() does not defer TLB flushes,
@@ -422,9 +436,8 @@ static inline long change_pmd_range(struct mmu_gather *tlb,
}
/* fall through, the trans huge pmd just split */
}
- this_pages = change_pte_range(tlb, vma, pmd, addr, next,
- newprot, cp_flags);
- pages += this_pages;
+ pages += change_pte_range(tlb, vma, pmd, addr, next,
+ newprot, cp_flags);
next:
cond_resched();
} while (pmd++, addr = next, addr != end);
@@ -443,12 +456,14 @@ static inline long change_pud_range(struct mmu_gather *tlb,
{
pud_t *pud;
unsigned long next;
- long pages = 0;
+ long pages = 0, ret;
pud = pud_offset(p4d, addr);
do {
next = pud_addr_end(addr, end);
- change_prepare(vma, pud, pmd, addr, cp_flags);
+ ret = change_prepare(vma, pud, pmd, addr, cp_flags);
+ if (ret)
+ return ret;
if (pud_none_or_clear_bad(pud))
continue;
pages += change_pmd_range(tlb, vma, pud, addr, next, newprot,
@@ -464,12 +479,14 @@ static inline long change_p4d_range(struct mmu_gather *tlb,
{
p4d_t *p4d;
unsigned long next;
- long pages = 0;
+ long pages = 0, ret;
p4d = p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
- change_prepare(vma, p4d, pud, addr, cp_flags);
+ ret = change_prepare(vma, p4d, pud, addr, cp_flags);
+ if (ret)
+ return ret;
if (p4d_none_or_clear_bad(p4d))
continue;
pages += change_pud_range(tlb, vma, p4d, addr, next, newprot,
@@ -486,14 +503,18 @@ static long change_protection_range(struct mmu_gather *tlb,
struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd;
unsigned long next;
- long pages = 0;
+ long pages = 0, ret;
BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr);
tlb_start_vma(tlb, vma);
do {
next = pgd_addr_end(addr, end);
- change_prepare(vma, pgd, p4d, addr, cp_flags);
+ ret = change_prepare(vma, pgd, p4d, addr, cp_flags);
+ if (ret) {
+ pages = ret;
+ break;
+ }
if (pgd_none_or_clear_bad(pgd))
continue;
pages += change_p4d_range(tlb, vma, pgd, addr, next, newprot,
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 65ad172add27..53c3d916ff66 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -710,11 +710,12 @@ ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long start,
mmap_changing, 0);
}
-void uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma,
+long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma,
unsigned long start, unsigned long len, bool enable_wp)
{
unsigned int mm_cp_flags;
struct mmu_gather tlb;
+ long ret;
if (enable_wp)
mm_cp_flags = MM_CP_UFFD_WP;
@@ -730,8 +731,10 @@ void uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma,
if (!enable_wp && vma_wants_manual_pte_write_upgrade(dst_vma))
mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE;
tlb_gather_mmu(&tlb, dst_mm);
- change_protection(&tlb, dst_vma, start, start + len, mm_cp_flags);
+ ret = change_protection(&tlb, dst_vma, start, start + len, mm_cp_flags);
tlb_finish_mmu(&tlb);
+
+ return ret;
}
int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
@@ -740,7 +743,7 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
{
struct vm_area_struct *dst_vma;
unsigned long page_mask;
- int err;
+ long err;
/*
* Sanitize the command parameters:
@@ -779,9 +782,12 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
goto out_unlock;
}
- uffd_wp_range(dst_mm, dst_vma, start, len, enable_wp);
+ err = uffd_wp_range(dst_mm, dst_vma, start, len, enable_wp);
+
+ /* Return 0 on success, <0 on failures */
+ if (err > 0)
+ err = 0;
- err = 0;
out_unlock:
mmap_read_unlock(dst_mm);
return err;
generated by cgit (git 2.34.1) at 2024-06-20 10:04:02 +0000