[PATCH] Driver core: platform: Add extra error check in devm_platform_get_irqs_affinity()

From: John Garry <john.garry@huawei.com>
To: <gregkh@linuxfoundation.org>, <rafael@kernel.org>,
	<maz@kernel.org>, <tglx@linutronix.de>
Cc: <linux-kernel@vger.kernel.org>, <dan.carpenter@oracle.com>,
	John Garry <john.garry@huawei.com>
Subject: [PATCH] Driver core: platform: Add extra error check in devm_platform_get_irqs_affinity()
Date: Mon, 21 Dec 2020 22:30:55 +0800	[thread overview]
Message-ID: <1608561055-231244-1-git-send-email-john.garry@huawei.com> (raw)

The current check of nvec < minvec for nvec returned from
platform_irq_count() will not detect a negative error code in nvec.

This is because minvec is unsigned, and, as such, nvec is promoted to
unsigned in that check, which will make it a huge number (if it contained
-EPROBE_DEFER).

In practice, an error should not occur in nvec for the only in-tree
user, but add a check anyway.

Fixes: e15f2fa959f2 ("driver core: platform: Add devm_platform_get_irqs_affinity()")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: John Garry <john.garry@huawei.com>
---
I hope that this can go through either irqchip or driver/core trees, thanks!

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 95fd1549f87d..8456d8384ac8 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -366,6 +366,8 @@ int devm_platform_get_irqs_affinity(struct platform_device *dev,
 		return -ERANGE;
 
 	nvec = platform_irq_count(dev);
+	if (nvec < 0)
+		return nvec;
 
 	if (nvec < minvec)
 		return -ENOSPC;
-- 
2.26.2

