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

Ye Liu <[email protected]> Wed, 5 Aug 2026 10:15:55 +0800
Newsgroups org.kvack.linux-mm,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
From: Ye Liu <[email protected]>

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 <[email protected]>
---
 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