[PATCH] genirq/proc: size IRQ directory names for 10-digit IRQ values

[Pengpeng Hou]

`/proc/irq/<n>/` directory names are built in `char name[10]` buffers
with `sprintf(name, "%u", irq)`.

Ten-digit IRQ numbers already need 11 bytes including the trailing NUL,
and current sparse-IRQ configurations still allow IRQ numbers in that
range.

Size the temporary name buffer for the current decimal form and switch
to bounded formatting when creating or removing the proc entry.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 kernel/irq/proc.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index b0999a4f1f68..dfa0b0723642 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -10,6 +10,7 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/interrupt.h>
+#include <linux/kernel.h>
 #include <linux/kernel_stat.h>
 #include <linux/mutex.h>
 #include <linux/string.h>
@@ -326,7 +327,7 @@ void register_handler_proc(unsigned int irq, struct irqaction *action)
 
 #undef MAX_NAMELEN
 
-#define MAX_NAMELEN 10
+#define MAX_NAMELEN 11
 
 void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 {
@@ -348,7 +349,7 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 		return;
 
 	/* create /proc/irq/1234 */
-	sprintf(name, "%u", irq);
+	snprintf(name, MAX_NAMELEN, "%u", irq);
 	desc->dir = proc_mkdir(name, root_irq_dir);
 	if (!desc->dir)
 		return;
@@ -401,7 +402,7 @@ void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
 #endif
 	remove_proc_entry("spurious", desc->dir);
 
-	sprintf(name, "%u", irq);
+	snprintf(name, MAX_NAMELEN, "%u", irq);
 	remove_proc_entry(name, root_irq_dir);
 }
 
-- 
2.50.1 (Apple Git-155)