Re: [PATCH] acpi/arm64: Adjust error handling procedure in gtdt_parse_timer_block()

From: Hanjun Guo
Date: Thu Aug 29 2024 - 09:53:00 EST


On 2024/8/27 18:12, Aleksandr Mishin wrote:
In case of error in gtdt_parse_timer_block() invalid 'gtdt_frame'
will be used in 'do {} while (i-- >= 0 && gtdt_frame--);' statement block
because do{} block will be executed even if 'i == 0'.

Adjust error handling procedure by replacing 'i-- >= 0' with 'i-- > 0'.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: a712c3ed9b8a ("acpi/arm64: Add memory-mapped timer support in GTDT driver")
Signed-off-by: Aleksandr Mishin <amishin@xxxxxxxxxx>
---
drivers/acpi/arm64/gtdt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c
index c0e77c1c8e09..eb6c2d360387 100644
--- a/drivers/acpi/arm64/gtdt.c
+++ b/drivers/acpi/arm64/gtdt.c
@@ -283,7 +283,7 @@ static int __init gtdt_parse_timer_block(struct acpi_gtdt_timer_block *block,
if (frame->virt_irq > 0)
acpi_unregister_gsi(gtdt_frame->virtual_timer_interrupt);
frame->virt_irq = 0;
- } while (i-- >= 0 && gtdt_frame--);
+ } while (i-- > 0 && gtdt_frame--);

Good catch,

Acked-by: Hanjun Guo <guohanjun@xxxxxxxxxx>

It's a fix in the error path, so I think it's OK for next release cycle.

Thanks
Hanjun