Re: [PATCH v2] coccinelle: api: check for propagation of error from platform_get_irq

From: Sergei Shtylyov
Date: Sat Dec 26 2015 - 17:27:27 EST


On 12/26/2015 11:58 PM, Julia Lawall wrote:

The error return value of platform_get_irq seems to often get dropped.

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>

---

v2: Check for the direct return case also. Added some mailing lists of
common offenders.

diff --git a/scripts/coccinelle/api/platform_get_irq_return.cocci b/scripts/coccinelle/api/platform_get_irq_return.cocci
new file mode 100644
index 0000000..44680d0
--- /dev/null
+++ b/scripts/coccinelle/api/platform_get_irq_return.cocci
@@ -0,0 +1,58 @@
+/// Propagate the return value of platform_get_irq.
+//# Sometimes the return value of platform_get_irq is tested using <= 0, but 0
+//# might not be an appropriate return value in an error case.
+///
+// Confidence: Moderate
+// Copyright: (C) 2015 Julia Lawall, Inria. GPLv2.
+// URL: http://coccinelle.lip6.fr/
+// Options: --no-includes --include-headers
+
+virtual context
+virtual org
+virtual report
+
+// ----------------------------------------------------------------------------
+
+@r depends on context || org || report@
+constant C;
+statement S;
+expression e, ret;
+position j0, j1;
+@@
+
+* e@j0 = platform_get_irq(...);
+(
+if@j1 (...) {
+ ...
+ return -C;
+} else S
+|
+if@j1 (...) {
+ ...
+ ret = -C;
+ ...
+ return ret;
+} else S

Well, this seems to also cover the (e <= 0) checks which do make same sense in the light of Linus considering IRQ0 invalid. So I'd be more specific about the checks here -- 0 should indeed be overridden with something if it's considered invalid.

MBR, Sergei

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