[symbolize] Fix bug in backtrace presenter
There was a bug in the backtrace presenter where header was assumed to be
non-nil. This caused a null reference exception when I tried to test kernel
crash symbolization.
Bug: ZX-2060 #comment Fix symbolize to handle no headers
Change-Id: Ief6f1d09280f5478b56d0fe0f80e71016aa47cdb
diff --git a/symbolize/demuxer_test.go b/symbolize/demuxer_test.go
index aa3cb73..11fbfe7 100644
--- a/symbolize/demuxer_test.go
+++ b/symbolize/demuxer_test.go
@@ -223,6 +223,47 @@
//[131.604] 01234.05678> Error at atan2 at atan2.c:49
}
+func ExampleNoHeaderBacktrace() {
+ // mock the input and outputs of llvm-symbolizer
+ symbo := newMockSymbolizer([]mockModule{
+ {"testdata/libc.elf", map[uint64][]SourceLocation{
+ 0x429c0: {{NewOptStr("math.h"), 51, NewOptStr("__DOUBLE_FLOAT")}, {NewOptStr("atan2.c"), 49, NewOptStr("atan2")}},
+ 0x43680: {{NewOptStr("pow.c"), 23, NewOptStr("pow")}},
+ 0x44987: {{NewOptStr("memcpy.c"), 76, NewOptStr("memcpy")}},
+ }},
+ })
+
+ // mock ids.txt
+ repo := NewRepo()
+ repo.AddSource(testBinaries)
+
+ // make a demuxer
+ demuxer := NewDemuxer(repo, symbo)
+
+ // define a little message that will need to be parsed
+ msg := "{{{module:1:libc.so:elf:4fcb712aa6387724a9f465a32cd8c14b}}}\n" +
+ "{{{mmap:0x12345000:0xcf6bc:load:1:rx:0x0}}}\n" +
+ "Backtrace:\n" +
+ "{{{bt:0:0x12388680}}}\n" +
+ "{{{bt:1:0x123879c0}}}\n"
+
+ // start sending InputLines to the demuxer
+ ctx := context.Background()
+ in := StartParsing(ctx, strings.NewReader(msg))
+ // start the demuxer which will cause filters to send output lines to 'out'
+ out := demuxer.Start(ctx, in)
+
+ Consume(ComposePostProcessors(ctx, out,
+ &FilterContextElements{},
+ NewBacktracePresenter(os.Stdout, NewBasicPresenter(os.Stdout, false))))
+
+ //Output:
+ //Backtrace:
+ // #0 0x0000000012388680 in pow pow.c:23 <libc.so>+0x43680
+ // #1.1 0x00000000123879c0 in __DOUBLE_FLOAT math.h:51 <libc.so>+0x429c0
+ // #1 0x00000000123879c0 in atan2 atan2.c:49 <libc.so>+0x429c0
+}
+
func ExampleNewBacktracePresenter() {
// mock the input and outputs of llvm-symbolizer
symbo := newMockSymbolizer([]mockModule{
diff --git a/symbolize/presenter.go b/symbolize/presenter.go
index 0049ac1..abae231 100644
--- a/symbolize/presenter.go
+++ b/symbolize/presenter.go
@@ -28,13 +28,17 @@
func printBacktrace(out io.Writer, hdr LineHeader, frame uint64, info addressInfo) {
modRelAddr := info.addr - info.seg.Vaddr + info.seg.ModRelAddr
+ var hdrString string
+ if hdr != nil {
+ hdrString = hdr.Present()
+ }
if len(info.locs) == 0 {
- fmt.Fprintf(out, "%s #%-4d %#016x in <%s>+%#x\n", hdr.Present(), frame, info.addr, info.mod.Name, modRelAddr)
+ fmt.Fprintf(out, "%s #%-4d %#016x in <%s>+%#x\n", hdrString, frame, info.addr, info.mod.Name, modRelAddr)
return
}
for i, loc := range info.locs {
i = len(info.locs) - i - 1
- fmt.Fprintf(out, "%s ", hdr.Present())
+ fmt.Fprintf(out, "%s ", hdrString)
var frameStr string
if i == 0 {
frameStr = fmt.Sprintf("#%d", frame)
