[PATCH] mm/show_mem: fix format string inconsistencies and type mismatches

[PATCH] mm/show_mem: fix format string inconsistencies and type mismatches

[Ye Liu]

From: Ye Liu <liuye@kylinos.cn>

Fix five format string issues in show_free_areas() and __show_mem():

1-2. reserved_highatomic and free_highatomic: %luKB -> %lukB
   The uppercase "KB" is inconsistent with all other fields in the
   same output block and with /proc/meminfo convention.

3. local_pcp: %ukB -> %lukB with explicit (unsigned long) cast
   per_cpu_pages.count is int, so K(count) yields int. Using %u
   was a signed/unsigned mismatch. Cast to unsigned long and use
   %lu for consistency with all other K() usages in the file.

4. total pagecache pages: %ld -> %lu
   global_node_page_state() returns unsigned long. Using %ld is a
   signedness mismatch caught by gcc -Wformat-signedness.

5. hwpoisoned pages: %lu -> %ld
   atomic_long_read() returns long (signed). Using %lu is a
   signedness mismatch caught by gcc -Wformat-signedness.

Verified with: make KCFLAGS="-Wformat -Wformat-signedness" mm/show_mem.o

Signed-off-by: Ye Liu <liuye@kylinos.cn>
---
 mm/show_mem.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/show_mem.c b/mm/show_mem.c
index d1288b4c2b64..b938cbcd774a 100644
--- a/mm/show_mem.c
+++ b/mm/show_mem.c
@@ -309,8 +309,8 @@ static void show_free_areas(unsigned int filter, const nodemask_t *nodemask,
 			" min:%lukB"
 			" low:%lukB"
 			" high:%lukB"
-			" reserved_highatomic:%luKB"
-			" free_highatomic:%luKB"
+			" reserved_highatomic:%lukB"
+			" free_highatomic:%lukB"
 			" active_anon:%lukB"
 			" inactive_anon:%lukB"
 			" active_file:%lukB"
@@ -323,7 +323,7 @@ static void show_free_areas(unsigned int filter, const nodemask_t *nodemask,
 			" mlocked:%lukB"
 			" bounce:%lukB"
 			" free_pcp:%lukB"
-			" local_pcp:%ukB"
+			" local_pcp:%lukB"
 			" free_cma:%lukB"
 			"\n",
 			zone->name,
@@ -350,7 +350,7 @@ static void show_free_areas(unsigned int filter, const nodemask_t *nodemask,
 			K(zone_page_state(zone, NR_MLOCK)),
 			0UL,
 			K(free_pcp),
-			K(this_cpu_read(zone->per_cpu_pageset->count)),
+			K((unsigned long)this_cpu_read(zone->per_cpu_pageset->count)),
 			K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
 		printk("lowmem_reserve[]:");
 		for (i = 0; i < MAX_NR_ZONES; i++)
@@ -400,7 +400,7 @@ static void show_free_areas(unsigned int filter, const nodemask_t *nodemask,
 		hugetlb_show_meminfo_node(nid);
 	}
 
-	printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
+	printk("%lu total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
 
 	show_swap_cache_info();
 }
@@ -430,7 +430,7 @@ void __show_mem(unsigned int filter, const nodemask_t *nodemask,
 	printk("%lu pages cma reserved\n", totalcma_pages);
 #endif
 #ifdef CONFIG_MEMORY_FAILURE
-	printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages));
+	printk("%ld pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages));
 #endif
 #ifdef CONFIG_MEM_ALLOC_PROFILING
 	static DEFINE_SPINLOCK(mem_alloc_profiling_spinlock);
-- 
2.25.1

Re: [PATCH] mm/show_mem: fix format string inconsistencies and type mismatches

[Vlastimil Babka (SUSE)]

On 8/5/26 04:15, Ye Liu wrote:
> From: Ye Liu <liuye@kylinos.cn>
> 
> Fix five format string issues in show_free_areas() and __show_mem():
> 
> 1-2. reserved_highatomic and free_highatomic: %luKB -> %lukB
>    The uppercase "KB" is inconsistent with all other fields in the
>    same output block and with /proc/meminfo convention.
> 
> 3. local_pcp: %ukB -> %lukB with explicit (unsigned long) cast
>    per_cpu_pages.count is int, so K(count) yields int. Using %u
>    was a signed/unsigned mismatch. Cast to unsigned long and use
>    %lu for consistency with all other K() usages in the file.
> 
> 4. total pagecache pages: %ld -> %lu
>    global_node_page_state() returns unsigned long. Using %ld is a
>    signedness mismatch caught by gcc -Wformat-signedness.
> 
> 5. hwpoisoned pages: %lu -> %ld
>    atomic_long_read() returns long (signed). Using %lu is a
>    signedness mismatch caught by gcc -Wformat-signedness.
> 
> Verified with: make KCFLAGS="-Wformat -Wformat-signedness" mm/show_mem.o
> 
> Signed-off-by: Ye Liu <liuye@kylinos.cn>

Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>

> ---
>  mm/show_mem.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/mm/show_mem.c b/mm/show_mem.c
> index d1288b4c2b64..b938cbcd774a 100644
> --- a/mm/show_mem.c
> +++ b/mm/show_mem.c
> @@ -309,8 +309,8 @@ static void show_free_areas(unsigned int filter, const nodemask_t *nodemask,
>  			" min:%lukB"
>  			" low:%lukB"
>  			" high:%lukB"
> -			" reserved_highatomic:%luKB"
> -			" free_highatomic:%luKB"
> +			" reserved_highatomic:%lukB"
> +			" free_highatomic:%lukB"
>  			" active_anon:%lukB"
>  			" inactive_anon:%lukB"
>  			" active_file:%lukB"
> @@ -323,7 +323,7 @@ static void show_free_areas(unsigned int filter, const nodemask_t *nodemask,
>  			" mlocked:%lukB"
>  			" bounce:%lukB"
>  			" free_pcp:%lukB"
> -			" local_pcp:%ukB"
> +			" local_pcp:%lukB"
>  			" free_cma:%lukB"
>  			"\n",
>  			zone->name,
> @@ -350,7 +350,7 @@ static void show_free_areas(unsigned int filter, const nodemask_t *nodemask,
>  			K(zone_page_state(zone, NR_MLOCK)),
>  			0UL,
>  			K(free_pcp),
> -			K(this_cpu_read(zone->per_cpu_pageset->count)),
> +			K((unsigned long)this_cpu_read(zone->per_cpu_pageset->count)),
>  			K(zone_page_state(zone, NR_FREE_CMA_PAGES)));
>  		printk("lowmem_reserve[]:");
>  		for (i = 0; i < MAX_NR_ZONES; i++)
> @@ -400,7 +400,7 @@ static void show_free_areas(unsigned int filter, const nodemask_t *nodemask,
>  		hugetlb_show_meminfo_node(nid);
>  	}
>  
> -	printk("%ld total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
> +	printk("%lu total pagecache pages\n", global_node_page_state(NR_FILE_PAGES));
>  
>  	show_swap_cache_info();
>  }
> @@ -430,7 +430,7 @@ void __show_mem(unsigned int filter, const nodemask_t *nodemask,
>  	printk("%lu pages cma reserved\n", totalcma_pages);
>  #endif
>  #ifdef CONFIG_MEMORY_FAILURE
> -	printk("%lu pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages));
> +	printk("%ld pages hwpoisoned\n", atomic_long_read(&num_poisoned_pages));
>  #endif
>  #ifdef CONFIG_MEM_ALLOC_PROFILING
>  	static DEFINE_SPINLOCK(mem_alloc_profiling_spinlock);

Re: [PATCH] mm/show_mem: fix format string inconsistencies and type mismatches

[Johannes Weiner]

On Wed, Aug 05, 2026 at 10:15:55AM +0800, Ye Liu wrote:
> From: Ye Liu <liuye@kylinos.cn>
> 
> Fix five format string issues in show_free_areas() and __show_mem():
> 
> 1-2. reserved_highatomic and free_highatomic: %luKB -> %lukB
>    The uppercase "KB" is inconsistent with all other fields in the
>    same output block and with /proc/meminfo convention.
> 
> 3. local_pcp: %ukB -> %lukB with explicit (unsigned long) cast
>    per_cpu_pages.count is int, so K(count) yields int. Using %u
>    was a signed/unsigned mismatch. Cast to unsigned long and use
>    %lu for consistency with all other K() usages in the file.
> 
> 4. total pagecache pages: %ld -> %lu
>    global_node_page_state() returns unsigned long. Using %ld is a
>    signedness mismatch caught by gcc -Wformat-signedness.
> 
> 5. hwpoisoned pages: %lu -> %ld
>    atomic_long_read() returns long (signed). Using %lu is a
>    signedness mismatch caught by gcc -Wformat-signedness.
> 
> Verified with: make KCFLAGS="-Wformat -Wformat-signedness" mm/show_mem.o
> 
> Signed-off-by: Ye Liu <liuye@kylinos.cn>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>