[igt-dev] [PATCH i-g-t v2] runner: Make taint abort messages more verbose

[Arkadiusz Hiler]

Since not everyone is familiar with kernel taints, and it is easy to get
confused and attribute an abort to an innocent TAINT_USER caused by an
unsafe module option, which is usually the first thing people find
greping dmesg for "taint", we should provide more guidance.

This patch extends the abort log by printing the taint names, as found
in the kernel, along with a short explanation, so people know what to
look for in the dmesg.

v2: rebase, reword

Cc: Petri Latvala <petri.latvala at intel.com>
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler at intel.com>
---
 runner/executor.c | 38 ++++++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/runner/executor.c b/runner/executor.c
index 54c530b7..c0639a66 100644
--- a/runner/executor.c
+++ b/runner/executor.c
@@ -137,13 +137,23 @@ static char *handle_lockdep(void)
 	return NULL;
 }
 
+/* see Linux's include/linux/kernel.h */
+static const struct {
+	unsigned long bit;
+	const char *explanation;
+} abort_taints[] = {
+  {(1 << 5), "TAINT_BAD_PAGE: Bad page reference or an unexpected page flags."},
+  {(1 << 7), "TAINT_DIE: Kernel has died - BUG/OOPS."},
+  {(1 << 9), "TAINT_WARN: WARN_ON has happened."},
+  {0, 0}};
+
 static unsigned long tainted(unsigned long *taints)
 {
-	const unsigned long bad_taints =
-		0x20  | /* TAINT_PAGE */
-		0x80  | /* TAINT_DIE */
-		0x200; /* TAINT_OOPS */
 	FILE *f;
+	unsigned long bad_taints = 0;
+
+	for (typeof(*abort_taints) *taint = abort_taints; taint->bit; taint++)
+		bad_taints |= taint->bit;
 
 	*taints = 0;
 
@@ -158,14 +168,26 @@ static unsigned long tainted(unsigned long *taints)
 
 static char *handle_taint(void)
 {
-	unsigned long taints, bad_taints;
+	unsigned long taints;
 	char *reason;
 
-	bad_taints = tainted(&taints);
-	if (!bad_taints)
+	if (!tainted(&taints))
 		return NULL;
 
-	asprintf(&reason, "Kernel tainted (%#lx -- %lx)", taints, bad_taints);
+	asprintf(&reason, "Kernel badly tainted (%#lx) (check dmesg for details):\n",
+		 taints);
+
+	for (typeof(*abort_taints) *taint = abort_taints; taint->bit; taint++) {
+		if (taint->bit & taints) {
+			char *old_reason = reason;
+			asprintf(&reason, "%s\t(%#lx) %s\n",
+					old_reason,
+					taint->bit,
+					taint->explanation);
+			free(old_reason);
+		}
+	}
+
 	return reason;
 }
 
-- 
2.19.2