[PATCH AUTOSEL 5.12 18/49] ARM: OMAP1: Fix use of possibly uninitialized irq variable

Sasha Levin
2021-06-07T16:13:34Z

From: Maciej Falkowski <maciej.falkowski9@gmail.com>

[ Upstream commit 3c4e0147c269738a19c7d70cd32395600bcc0714 ]

The current control flow of IRQ number assignment to `irq` variable
allows a request of IRQ of unspecified value,
generating a warning under Clang compilation with omap1_defconfig on
linux-next:

arch/arm/mach-omap1/pm.c:656:11: warning: variable 'irq' is used
uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
else if (cpu_is_omap16xx())
^~~~~~~~~~~~~~~~~
./arch/arm/mach-omap1/include/mach/soc.h:123:30: note: expanded from macro
'cpu_is_omap16xx'
^~~~~~~~~~~~~
arch/arm/mach-omap1/pm.c:658:18: note: uninitialized use occurs here
if (request_irq(irq, omap_wakeup_interrupt, 0, "peripheral wakeup",
^~~
arch/arm/mach-omap1/pm.c:656:7: note: remove the 'if' if its condition is
always true
else if (cpu_is_omap16xx())
^~~~~~~~~~~~~~~~~~~~~~
arch/arm/mach-omap1/pm.c:611:9: note: initialize the variable 'irq' to
silence this warning
int irq;
^
= 0
1 warning generated.

The patch provides a default value to the `irq` variable
along with a validity check.

Signed-off-by: Maciej Falkowski <maciej.falkowski9@gmail.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1324
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/mach-omap1/pm.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-omap1/pm.c b/arch/arm/mach-omap1/pm.c
index 2c1e2b32b9b3..a745d64d4699 100644
--- a/arch/arm/mach-omap1/pm.c
+++ b/arch/arm/mach-omap1/pm.c
@@ -655,9 +655,13 @@ static int __init omap_pm_init(void)
irq = INT_7XX_WAKE_UP_REQ;
else if (cpu_is_omap16xx())
irq = INT_1610_WAKE_UP_REQ;
- if (request_irq(irq, omap_wakeup_interrupt, 0, "peripheral wakeup",
- NULL))
- pr_err("Failed to request irq %d (peripheral wakeup)\n", irq);
+ else
+ irq = -1;
+
+ if (irq >= 0) {
+ if (request_irq(irq, omap_wakeup_interrupt, 0, "peripheral wakeup", NULL))
+ pr_err("Failed to request irq %d (peripheral wakeup)\n", irq);
+ }

/* Program new power ramp-up time
* (0 for most boards since we don't lower voltage when in deep sleep)
--
2.30.2