On Thu, 12 Dec 2019 12:29:49 +0300 Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> Hello Andrew Morton,
>
> The patch 3264ba9274f5: "mm-add-apply_to_existing_pages-helper-fix"
> from Dec 11, 2019, leads to the following static checker warning:
>
> mm/memory.c:2166 __apply_to_page_range()
> error: uninitialized symbol 'err'.
>
> mm/memory.c
> 2144 static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
> 2145 unsigned long size, pte_fn_t fn,
> 2146 void *data, bool create)
> 2147 {
> 2148 pgd_t *pgd;
> 2149 unsigned long next;
> 2150 unsigned long end = addr + size;
> 2151 int err;
> 2152
> 2153 if (WARN_ON(addr >= end))
> 2154 return -EINVAL;
> 2155
> 2156 pgd = pgd_offset(mm, addr);
> 2157 do {
> 2158 next = pgd_addr_end(addr, end);
> 2159 if (!create && pgd_none_or_clear_bad(pgd))
> 2160 continue;
> ^^^^^^^^^
> It feels unlikely that we would always hit this continue but Smatch
> complains.
>
Thanks.
--- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix-fix-fix
+++ a/mm/memory.c
@@ -2148,7 +2148,7 @@ static int __apply_to_page_range(struct
pgd_t *pgd;
unsigned long next;
unsigned long end = addr + size;
- int err;
+ int err = 0;
if (WARN_ON(addr >= end))
return -EINVAL;
Daniel, have you had a chance to runtime test these various fiddles?
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm-add-apply_to_existing_pages-helper-fix
reduce code duplication
Cc: Daniel Axtens <dja@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 43 +++++++++++++++++--------------------------
1 file changed, 17 insertions(+), 26 deletions(-)
--- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix
+++ a/mm/memory.c
@@ -2141,12 +2141,9 @@ static int apply_to_p4d_range(struct mm_
return err;
}
-/*
- * Scan a region of virtual memory, filling in page tables as necessary
- * and calling a provided function on each leaf page table.
- */
-int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
- unsigned long size, pte_fn_t fn, void *data)
+static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
+ unsigned long size, pte_fn_t fn,
+ void *data, bool create)
{
pgd_t *pgd;
unsigned long next;
@@ -2159,13 +2156,25 @@ int apply_to_page_range(struct mm_struct
pgd = pgd_offset(mm, addr);
do {
next = pgd_addr_end(addr, end);
- err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, true);
+ if (!create && pgd_none_or_clear_bad(pgd))
+ continue;
+ err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create);
if (err)
break;
} while (pgd++, addr = next, addr != end);
return err;
}
+
+/*
+ * Scan a region of virtual memory, filling in page tables as necessary
+ * and calling a provided function on each leaf page table.
+ */
+int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
+ unsigned long size, pte_fn_t fn, void *data)
+{
+ return __apply_to_page_range(mm, addr, size, fn, data, true);
+}
EXPORT_SYMBOL_GPL(apply_to_page_range);
/*
@@ -2178,25 +2187,7 @@ EXPORT_SYMBOL_GPL(apply_to_page_range);
int apply_to_existing_pages(struct mm_struct *mm, unsigned long addr,
unsigned long size, pte_fn_t fn, void *data)
{
- pgd_t *pgd;
- unsigned long next;
- unsigned long end = addr + size;
- int err = 0;
-
- if (WARN_ON(addr >= end))
- return -EINVAL;
-
- pgd = pgd_offset(mm, addr);
- do {
- next = pgd_addr_end(addr, end);
- if (pgd_none_or_clear_bad(pgd))
- continue;
- err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, false);
- if (err)
- break;
- } while (pgd++, addr = next, addr != end);
-
- return err;
+ return __apply_to_page_range(mm, addr, size, fn, data, false);
}
EXPORT_SYMBOL_GPL(apply_to_existing_pages);
_
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm-add-apply_to_existing_pages-helper-fix-fix
s/apply_to_existing_pages/apply_to_existing_page_range/
Cc: Daniel Axtens <dja@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 6 +++---
mm/memory.c | 6 +++---
2 files changed, 6 insertions(+), 6 deletions(-)
--- a/include/linux/mm.h~mm-add-apply_to_existing_pages-helper-fix-fix
+++ a/include/linux/mm.h
@@ -2621,9 +2621,9 @@ static inline int vm_fault_to_errno(vm_f
typedef int (*pte_fn_t)(pte_t *pte, unsigned long addr, void *data);
extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
unsigned long size, pte_fn_t fn, void *data);
-extern int apply_to_existing_pages(struct mm_struct *mm, unsigned long address,
- unsigned long size, pte_fn_t fn,
- void *data);
+extern int apply_to_existing_page_range(struct mm_struct *mm,
+ unsigned long address, unsigned long size,
+ pte_fn_t fn, void *data);
#ifdef CONFIG_PAGE_POISONING
extern bool page_poisoning_enabled(void);
--- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix-fix
+++ a/mm/memory.c
@@ -2184,12 +2184,12 @@ EXPORT_SYMBOL_GPL(apply_to_page_range);
* Unlike apply_to_page_range, this does _not_ fill in page tables
* where they are absent.
*/
-int apply_to_existing_pages(struct mm_struct *mm, unsigned long addr,
- unsigned long size, pte_fn_t fn, void *data)
+int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr,
+ unsigned long size, pte_fn_t fn, void *data)
{
return __apply_to_page_range(mm, addr, size, fn, data, false);
}
-EXPORT_SYMBOL_GPL(apply_to_existing_pages);
+EXPORT_SYMBOL_GPL(apply_to_existing_page_range);
/*
* handle_pte_fault chooses page fault handler according to an entry which was
_
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm-add-apply_to_existing_pages-helper-fix-fix-fix
initialize __apply_to_page_range::err
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Daniel Axtens <dja@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/memory.c~mm-add-apply_to_existing_pages-helper-fix-fix-fix
+++ a/mm/memory.c
@@ -2148,7 +2148,7 @@ static int __apply_to_page_range(struct
pgd_t *pgd;
unsigned long next;
unsigned long end = addr + size;
- int err;
+ int err = 0;
if (WARN_ON(addr >= end))
return -EINVAL;
_
