[PATCH v2] PCI: octep: Size the interrupt name buffer for the full format range

[PATCH v2] PCI: octep: Size the interrupt name buffer for the full format range

[xujiahao]

octep_hp_request_irq() formats the interrupt name with "octep_hp_%d"
into a 16-byte array.  The prefix is 9 bytes and a full-range %d
argument can add up to 11 more, so the worst case needs 21 bytes
including the terminator and 0-day reports:

  drivers/pci/hotplug/octep_hp.c:312:53: warning: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size 7 [-Wformat-truncation=]
  note: 'snprintf' output between 11 and 20 bytes into a destination of size 16

The values passed today are OCTEP_HP_INTR_ENA (0) and OCTEP_HP_INTR_DIS (1),
so no truncation actually happens, but the buffer carries no margin over the
format's worst case.  Give it the room so the warning stops coming back from
builds that cannot narrow the argument.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202507261457.SXXHOjUk-lkp@intel.com/
Signed-off-by: xujiahao <xujiahao@cmss.chinamobile.com>
---
Changes in v2:
- Keep the compiler warning text on single lines so it stays greppable in
  the git log (Bjorn Helgaas)
- Capitalize the subject to match drivers/pci/hotplug/ style (Bjorn Helgaas)
- Spell out the enum values passed to the format (Bjorn Helgaas)
---
 drivers/pci/hotplug/octep_hp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/hotplug/octep_hp.c b/drivers/pci/hotplug/octep_hp.c
index a0a7f9ccb..801c080e6 100644
--- a/drivers/pci/hotplug/octep_hp.c
+++ b/drivers/pci/hotplug/octep_hp.c
@@ -52,7 +52,7 @@ struct octep_hp_slot {
 struct octep_hp_intr_info {
 	enum octep_hp_intr_type type;
 	int number;
-	char name[16];
+	char name[24];
 };
 
 struct octep_hp_controller {
-- 
2.43.0

Re: [PATCH v2] PCI: octep: Size the interrupt name buffer for the full format range

[Bjorn Helgaas]

On Fri, Nov 06, 2026 at 09:21:26AM +0800, xujiahao wrote:
> octep_hp_request_irq() formats the interrupt name with "octep_hp_%d"
> into a 16-byte array.  The prefix is 9 bytes and a full-range %d
> argument can add up to 11 more, so the worst case needs 21 bytes
> including the terminator and 0-day reports:
> 
>   drivers/pci/hotplug/octep_hp.c:312:53: warning: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size 7 [-Wformat-truncation=]
>   note: 'snprintf' output between 11 and 20 bytes into a destination of size 16
> 
> The values passed today are OCTEP_HP_INTR_ENA (0) and OCTEP_HP_INTR_DIS (1),
> so no truncation actually happens, but the buffer carries no margin over the
> format's worst case.  Give it the room so the warning stops coming back from
> builds that cannot narrow the argument.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202507261457.SXXHOjUk-lkp@intel.com/
> Signed-off-by: xujiahao <xujiahao@cmss.chinamobile.com>

Applied to pci/hotplug for v7.5, thank you!

> ---
> Changes in v2:
> - Keep the compiler warning text on single lines so it stays greppable in
>   the git log (Bjorn Helgaas)
> - Capitalize the subject to match drivers/pci/hotplug/ style (Bjorn Helgaas)
> - Spell out the enum values passed to the format (Bjorn Helgaas)
> ---
>  drivers/pci/hotplug/octep_hp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/hotplug/octep_hp.c b/drivers/pci/hotplug/octep_hp.c
> index a0a7f9ccb..801c080e6 100644
> --- a/drivers/pci/hotplug/octep_hp.c
> +++ b/drivers/pci/hotplug/octep_hp.c
> @@ -52,7 +52,7 @@ struct octep_hp_slot {
>  struct octep_hp_intr_info {
>  	enum octep_hp_intr_type type;
>  	int number;
> -	char name[16];
> +	char name[24];
>  };
>  
>  struct octep_hp_controller {
> -- 
> 2.43.0
> 
> 
>