From 88bc17df053022a7c2a3753b299b06a9eff19c1a Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Mon, 12 Feb 2018 11:26:51 +0100
Subject: pkg/report: improve corrupted report detection

Detect informational kernel reports that are not bugs in itself,
but contain stack traces. If we see them in the middle of another
report, we know stacks are intermixed and the report is potentially
corrupted.
---
 pkg/report/linux.go | 47 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 10 deletions(-)

(limited to 'pkg/report/linux.go')

diff --git a/pkg/report/linux.go b/pkg/report/linux.go
index e0f47df54..1892f2266 100644
--- a/pkg/report/linux.go
+++ b/pkg/report/linux.go
@@ -19,16 +19,17 @@ import (
 )
 
 type linux struct {
-	kernelSrc           string
-	kernelObj           string
-	vmlinux             string
-	symbols             map[string][]symbolizer.Symbol
-	ignores             []*regexp.Regexp
-	consoleOutputRe     *regexp.Regexp
-	questionableRe      *regexp.Regexp
-	guiltyFileBlacklist []*regexp.Regexp
-	reportStartIgnores  [][]byte
-	eoi                 []byte
+	kernelSrc             string
+	kernelObj             string
+	vmlinux               string
+	symbols               map[string][]symbolizer.Symbol
+	ignores               []*regexp.Regexp
+	consoleOutputRe       *regexp.Regexp
+	questionableRe        *regexp.Regexp
+	guiltyFileBlacklist   []*regexp.Regexp
+	reportStartIgnores    [][]byte
+	infoMessagesWithStack [][]byte
+	eoi                   []byte
 }
 
 func ctorLinux(kernelSrc, kernelObj string, symbols map[string][]symbolizer.Symbol,
@@ -84,6 +85,13 @@ func ctorLinux(kernelSrc, kernelObj string, symbols map[string][]symbolizer.Symb
 		[]byte("invalid opcode: 0000"),
 		[]byte("Kernel panic - not syncing: panic_on_warn set"),
 	}
+	// These pattern math kernel reports which are not bugs in itself but contain stack traces.
+	// If we see them in the middle of another report, we know that the report is potentially corrupted.
+	ctx.infoMessagesWithStack = [][]byte{
+		[]byte("vmalloc: allocation failure:"),
+		[]byte("FAULT_INJECTION: forcing a failure"),
+		[]byte("FAULT_FLAG_ALLOW_RETRY missing"),
+	}
 	return ctx, nil
 }
 
@@ -114,6 +122,14 @@ func (ctx *linux) Parse(output []byte) *Report {
 		for _, oops1 := range linuxOopses {
 			match := matchOops(line, oops1, ctx.ignores)
 			if match == -1 {
+				if oops != nil && secondReportPos == 0 {
+					for _, pattern := range ctx.infoMessagesWithStack {
+						if bytes.Contains(line, pattern) {
+							secondReportPos = pos
+							break
+						}
+					}
+				}
 				continue
 			}
 			if oops == nil {
@@ -873,6 +889,17 @@ var linuxOopses = []*oops{
 				report: compile("INFO: inconsistent lock state \\](?:.*\\n)+?.*takes(?:.*\\n)+?.*at: {{PC}} +{{FUNC}}"),
 				fmt:    "inconsistent lock state in %[1]v",
 			},
+			{
+				title: linuxRcuStall,
+				fmt:   "INFO: rcu detected stall in %[1]v",
+				stack: &stackFmt{
+					parts: []*regexp.Regexp{
+						compile("apic_timer_interrupt"),
+						parseStackTrace,
+					},
+					skip: []string{"apic_timer_interrupt", "rcu"},
+				},
+			},
 			{
 				title: linuxRcuStall,
 				fmt:   "INFO: rcu detected stall in %[1]v",
-- 
cgit mrf-deployment