[PATCH v2 3/3] mm: use vma_start_write_killable() in process_vma_walk_lock()
Suren Baghdasaryan
surenb at google.com
Wed Feb 18 03:32:50 AEDT 2026
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.
Signed-off-by: Suren Baghdasaryan <surenb at google.com>
---
arch/s390/kvm/kvm-s390.c | 5 +++--
arch/s390/mm/gmap.c | 13 ++++++++++---
fs/proc/task_mmu.c | 7 ++++++-
mm/pagewalk.c | 20 ++++++++++++++------
4 files changed, 33 insertions(+), 12 deletions(-)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 56a50524b3ee..75aef9c66e03 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -958,6 +958,7 @@ static int kvm_s390_get_mem_control(struct kvm *kvm, struct kvm_device_attr *att
static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *attr)
{
int ret;
+ int err;
unsigned int idx;
switch (attr->attr) {
case KVM_S390_VM_MEM_ENABLE_CMMA:
@@ -990,10 +991,10 @@ static int kvm_s390_set_mem_control(struct kvm *kvm, struct kvm_device_attr *att
VM_EVENT(kvm, 3, "%s", "RESET: CMMA states");
mutex_lock(&kvm->lock);
idx = srcu_read_lock(&kvm->srcu);
- s390_reset_cmma(kvm->arch.gmap->mm);
+ err = s390_reset_cmma(kvm->arch.gmap->mm);
srcu_read_unlock(&kvm->srcu, idx);
mutex_unlock(&kvm->lock);
- ret = 0;
+ ret = (err < 0) ? err : 0;
break;
case KVM_S390_VM_MEM_LIMIT_SIZE: {
unsigned long new_limit;
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index dd85bcca817d..96054b124db5 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2271,6 +2271,7 @@ int s390_enable_skey(void)
{
struct mm_struct *mm = current->mm;
int rc = 0;
+ int err;
mmap_write_lock(mm);
if (mm_uses_skeys(mm))
@@ -2282,7 +2283,9 @@ int s390_enable_skey(void)
mm->context.uses_skeys = 0;
goto out_up;
}
- walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
+ err = walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
+ if (err < 0)
+ rc = err;
out_up:
mmap_write_unlock(mm);
@@ -2305,11 +2308,15 @@ static const struct mm_walk_ops reset_cmma_walk_ops = {
.walk_lock = PGWALK_WRLOCK,
};
-void s390_reset_cmma(struct mm_struct *mm)
+int s390_reset_cmma(struct mm_struct *mm)
{
+ int err;
+
mmap_write_lock(mm);
- walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
+ err = walk_page_range(mm, 0, TASK_SIZE, &reset_cmma_walk_ops, NULL);
mmap_write_unlock(mm);
+
+ return (err < 0) ? err : 0;
}
EXPORT_SYMBOL_GPL(s390_reset_cmma);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index d7d52e259055..91e806d65bd9 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1797,6 +1797,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
struct clear_refs_private cp = {
.type = type,
};
+ int err;
if (mmap_write_lock_killable(mm)) {
count = -EINTR;
@@ -1824,7 +1825,11 @@ 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 (err < 0) {
+ count = err;
+ goto out_unlock;
+ }
if (type == CLEAR_REFS_SOFT_DIRTY) {
mmu_notifier_invalidate_range_end(&range);
flush_tlb_mm(mm);
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index a94c401ab2cf..dc9f7a7709c6 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -425,14 +425,13 @@ 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,
+static inline 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;
@@ -444,6 +443,7 @@ static inline void process_vma_walk_lock(struct vm_area_struct *vma,
break;
}
#endif
+ return 0;
}
/*
@@ -487,7 +487,9 @@ 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);
@@ -704,6 +706,7 @@ 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;
@@ -711,7 +714,9 @@ 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);
}
@@ -734,6 +739,7 @@ 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;
@@ -741,7 +747,9 @@ 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);
}
--
2.53.0.273.g2a3d683680-goog
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