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

[Aleksandr Mishin]

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 at t-argos.ru>
---
 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--);
 
 	return -EINVAL;
 }
-- 
2.30.2