[PATCH 38/41] mm: avoid assertion in untrack_pfn
From: Suren Baghdasaryan
Date: Mon Jan 09 2023 - 15:59:28 EST
untrack_pfn can be called after VMA was isolated and mmap_lock downgraded.
An attempt to lock affected VMA would cause an assertion, therefore
use mod_vm_flags_nolock in such situations.
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
---
arch/x86/mm/pat/memtype.c | 10 +++++++---
include/linux/mm.h | 2 +-
include/linux/pgtable.h | 5 +++--
mm/memory.c | 15 ++++++++-------
mm/memremap.c | 4 ++--
mm/mmap.c | 4 ++--
6 files changed, 23 insertions(+), 17 deletions(-)
diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index 9e490a372896..f71c8381430b 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -1045,7 +1045,7 @@ void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, pfn_t pfn)
* can be for the entire vma (in which case pfn, size are zero).
*/
void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
- unsigned long size)
+ unsigned long size, bool lock_vma)
{
resource_size_t paddr;
unsigned long prot;
@@ -1064,8 +1064,12 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
size = vma->vm_end - vma->vm_start;
}
free_pfn_range(paddr, size);
- if (vma)
- clear_vm_flags(vma, VM_PAT);
+ if (vma) {
+ if (lock_vma)
+ clear_vm_flags(vma, VM_PAT);
+ else
+ mod_vm_flags_nolock(vma, 0, VM_PAT);
+ }
}
/*
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7d436a5027cc..3158f33e268c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2135,7 +2135,7 @@ void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
unsigned long size, struct zap_details *details);
void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt,
struct vm_area_struct *start_vma, unsigned long start,
- unsigned long end);
+ unsigned long end, bool lock_vma);
struct mmu_notifier_range;
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 1159b25b0542..eaa831bd675d 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1214,7 +1214,8 @@ static inline int track_pfn_copy(struct vm_area_struct *vma)
* can be for the entire vma (in which case pfn, size are zero).
*/
static inline void untrack_pfn(struct vm_area_struct *vma,
- unsigned long pfn, unsigned long size)
+ unsigned long pfn, unsigned long size,
+ bool lock_vma)
{
}
@@ -1232,7 +1233,7 @@ extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
pfn_t pfn);
extern int track_pfn_copy(struct vm_area_struct *vma);
extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
- unsigned long size);
+ unsigned long size, bool lock_vma);
extern void untrack_pfn_moved(struct vm_area_struct *vma);
#endif
diff --git a/mm/memory.c b/mm/memory.c
index 12508f4d845a..5c7d5eaa60d8 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1610,7 +1610,7 @@ void unmap_page_range(struct mmu_gather *tlb,
static void unmap_single_vma(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long start_addr,
unsigned long end_addr,
- struct zap_details *details)
+ struct zap_details *details, bool lock_vma)
{
unsigned long start = max(vma->vm_start, start_addr);
unsigned long end;
@@ -1625,7 +1625,7 @@ static void unmap_single_vma(struct mmu_gather *tlb,
uprobe_munmap(vma, start, end);
if (unlikely(vma->vm_flags & VM_PFNMAP))
- untrack_pfn(vma, 0, 0);
+ untrack_pfn(vma, 0, 0, lock_vma);
if (start != end) {
if (unlikely(is_vm_hugetlb_page(vma))) {
@@ -1672,7 +1672,7 @@ static void unmap_single_vma(struct mmu_gather *tlb,
*/
void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt,
struct vm_area_struct *vma, unsigned long start_addr,
- unsigned long end_addr)
+ unsigned long end_addr, bool lock_vma)
{
struct mmu_notifier_range range;
struct zap_details details = {
@@ -1686,7 +1686,8 @@ void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt,
start_addr, end_addr);
mmu_notifier_invalidate_range_start(&range);
do {
- unmap_single_vma(tlb, vma, start_addr, end_addr, &details);
+ unmap_single_vma(tlb, vma, start_addr, end_addr, &details,
+ lock_vma);
} while ((vma = mas_find(&mas, end_addr - 1)) != NULL);
mmu_notifier_invalidate_range_end(&range);
}
@@ -1715,7 +1716,7 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long start,
update_hiwater_rss(vma->vm_mm);
mmu_notifier_invalidate_range_start(&range);
do {
- unmap_single_vma(&tlb, vma, start, range.end, NULL);
+ unmap_single_vma(&tlb, vma, start, range.end, NULL, false);
} while ((vma = mas_find(&mas, end - 1)) != NULL);
mmu_notifier_invalidate_range_end(&range);
tlb_finish_mmu(&tlb);
@@ -1750,7 +1751,7 @@ void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
* unmap 'address-end' not 'range.start-range.end' as range
* could have been expanded for hugetlb pmd sharing.
*/
- unmap_single_vma(&tlb, vma, address, end, details);
+ unmap_single_vma(&tlb, vma, address, end, details, false);
mmu_notifier_invalidate_range_end(&range);
tlb_finish_mmu(&tlb);
}
@@ -2519,7 +2520,7 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
err = remap_pfn_range_notrack(vma, addr, pfn, size, prot);
if (err)
- untrack_pfn(vma, pfn, PAGE_ALIGN(size));
+ untrack_pfn(vma, pfn, PAGE_ALIGN(size), true);
return err;
}
EXPORT_SYMBOL(remap_pfn_range);
diff --git a/mm/memremap.c b/mm/memremap.c
index 08cbf54fe037..2f88f43d4a01 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -129,7 +129,7 @@ static void pageunmap_range(struct dev_pagemap *pgmap, int range_id)
}
mem_hotplug_done();
- untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range));
+ untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);
pgmap_array_delete(range);
}
@@ -276,7 +276,7 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
if (!is_private)
kasan_remove_zero_shadow(__va(range->start), range_len(range));
err_kasan:
- untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range));
+ untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true);
err_pfn_remap:
pgmap_array_delete(range);
return error;
diff --git a/mm/mmap.c b/mm/mmap.c
index a256deca0bc0..332af383f7cd 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2209,7 +2209,7 @@ static void unmap_region(struct mm_struct *mm, struct maple_tree *mt,
lru_add_drain();
tlb_gather_mmu(&tlb, mm);
update_hiwater_rss(mm);
- unmap_vmas(&tlb, mt, vma, start, end);
+ unmap_vmas(&tlb, mt, vma, start, end, lock_vma);
free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS,
next ? next->vm_start : USER_PGTABLES_CEILING,
lock_vma);
@@ -3127,7 +3127,7 @@ void exit_mmap(struct mm_struct *mm)
tlb_gather_mmu_fullmm(&tlb, mm);
/* update_hiwater_rss(mm) here? but nobody should be looking */
/* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */
- unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX);
+ unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX, false);
mmap_read_unlock(mm);
/*
--
2.39.0