Re: [libvirt] [PATCH 4/4] Introduce new OOM testing support

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; The previous OOM testing support would re-run the entire "main" method each iteration, failing a different malloc each time. When a test suite has 'n' allocations, the number of repeats requires is (n * (n + 1) ) / 2. This gets very large, very quickly. This new OOM testing support instead integrates at the virtTestRun level, so each individual test case gets repeated, instead of the entire test suite. This means the values of 'n' are orders of magnitude smaller.

The simple usage is $ VIR_TEST_OOM=1 ./qemuxml2argvtest ... 29) QEMU XML-2-ARGV clock-utc ... OK Test OOM for nalloc=36 .................................... OK 30) QEMU XML-2-ARGV clock-localtime ... OK Test OOM for nalloc=36 .................................... OK 31) QEMU XML-2-ARGV clock-france ... OK Test OOM for nalloc=38 ...................................... OK ... the second lines reports how many mallocs have to be failed, and thus how many repeats of the test wil be run.

If it crashes, then running under valgrind will often show the problem $ VIR_TEST_OOM=1 ../run valgrind ./qemuxml2argvtest When debugging problems it is also helpful to select an individual test case $ VIR_TEST_RANGE=30 VIR_TEST_OOM=1 ../run valgrind ./qemuxml2argvtest When things get really tricky, it is possible to request that just specific allocs are failed. eg to fail allocs 5 -> 12, use $ VIR_TEST_RANGE=30 VIR_TEST_OOM=1:5-12 ../run valgrind ./qemuxml2argvtest

In the worse case, you might want to know the stack trace of the alloc which was failed then VIR_TEST_OOM_TRACE can be set. If it is set to 1 then it will only print if it things a mistake happened.

This is often not reliable, so setting it to 2 will make it print the stack trace for every alloc that is failed. $ VIR_TEST_OOM_TRACE=2 VIR_TEST_RANGE=30 VIR_TEST_OOM=1:5-5 ../run valgrind ./qemuxml2argvtest 30) QEMU XML-2-ARGV clock-localtime ... OK Test OOM for nalloc=36 !virAllocN /home/berrange/src/virt/libvirt/src/util/viralloc.c:180 virHashCreateFull /home/berrange/src/virt/libvirt/src/util/virhash.c:144 virDomainDefParseXML /home/berrange/src/virt/libvirt/src/conf/domain_conf.c:11745 virDomainDefParseNode /home/berrange/src/virt/libvirt/src/conf/domain_conf.c:12646 virDomainDefParse /home/berrange/src/virt/libvirt/src/conf/domain_conf.c:12590 testCompareXMLToArgvFiles /home/berrange/src/virt/libvirt/tests/qemuxml2argvtest.c:106 virtTestRun /home/berrange/src/virt/libvirt/tests/testutils.c:250 mymain /home/berrange/src/virt/libvirt/tests/qemuxml2argvtest.c:418 (discriminator 2) virtTestMain /home/berrange/src/virt/libvirt/tests/testutils.c:750 ?? ??:0 _start ??:? FAILED Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- tests/cputest.c | 3 +- tests/qemuargv2xmltest.c | 14 ++-- tests/qemuxml2argvtest.c | 12 ++- tests/qemuxmlnstest.c | 18 +++-- tests/testutils.c | 189 ++++++++++++++++++++++++++++++++++++++++++++++- tests/testutils.h | 2 + 6 files changed, 216 insertions(+), 22 deletions(-) diff --git a/tests/cputest.c b/tests/cputest.c index 8e3640b..17cb6af 100644 --- a/tests/cputest.c +++ b/tests/cputest.c @@ -476,7 +476,8 @@ cpuTestRun(const char *name, const struct data *data) if (virTestGetDebug()) { char *log; if ((log = virtTestLogContentAndReset()) && - strlen(log) > 0) + log != NULL && + strlen(log) > 0)

+++ b/tests/testutils.c @@ -47,6 +47,9 @@ #include "virprocess.h" #include "virstring.h" +#include <dlfcn.h> +#include <execinfo.h>

+#ifdef TEST_OOM +static unsigned int testOOM = 0; +static unsigned int testOOMStart = -1; +static unsigned int testOOMEnd = -1; +static unsigned int testOOMTrace = 0; +# ifdef TEST_OOM_TRACE

+virTestShowTrace(void) +{ + size_t j; + for (j = 2; j < ntestAllocStack; j++) { + Dl_info info; + char *cmd; + + dladdr(testAllocStack[j], &info); + if (info.dli_fname && + strstr(info.dli_fname, ".so")) { + if (virAsprintf(&cmd, "addr2line -f -e %s %p", + info.dli_fname, + ((void*)((unsigned long long)testAllocStack[j] + - (unsigned long long)info.dli_fbase))) < 0) + continue; + } else { + if (virAsprintf(&cmd, "addr2line -f -e %s %p", + (char*)(info.dli_fname ? info.dli_fname : "<unknown>"), + testAllocStack[j]) < 0) + continue; + } + ignore_value(system(cmd));

@@ -168,7 +226,7 @@ virtTestRun(const char *title, !((testCounter-1) % 40)) { fprintf(stderr, " %-3zu\n", (testCounter-1)); fprintf(stderr, " "); - } + }

+ testOOMActive = true; + for (i = start; i < end; i++) { + bool missingFail = false; +# ifdef TEST_OOM_TRACE + memset(testAllocStack, 0, ARRAY_CARDINALITY(testAllocStack)); + ntestAllocStack = 0; +# endif + virAllocTestOOM(i+1, 1);

+ oomret = body(data); + + /* fprintf() disabled because XML parsing APIs don't allow + * distinguish between element / attribute not present + * in the XML (which is non-fatal), vs OOM / malformed + * which should be fatal. Thus error reporting for + * optionally present XML is mostly broken. + */ + if (oomret == 0) { + missingFail = true; +# if 0 + fprintf(stderr, " alloc %zu failed but no err status\n", i + 1); +# endif + } else { + virErrorPtr lerr = virGetLastError(); + if (!lerr) { +# if 0 + fprintf(stderr, " alloc %zu failed but no error report\n", i + 1); +# endif + missingFail = true; + } + } + if ((missingFail && testOOMTrace) || (testOOMTrace > 1)) {

+ fprintf(stderr, "%s", "!"); +# ifdef TEST_OOM_TRACE + virTestShowTrace(); +# endif + ret = -1; + } else { + fprintf(stderr, "%s", "."); + } + } + testOOMActive = false; + if (ret == 0) + fprintf(stderr, " OK\n"); + else + fprintf(stderr, " FAILED\n"); + virAllocTestInit(); + } +#endif /* TEST_OOM */ + return ret; } @@ -205,7 +334,7 @@ virtTestLoadFile(const char *file, char **buf) tmplen = buflen = st.st_size + 1; if (VIR_ALLOC_N(*buf, buflen) < 0) { - fprintf(stderr, "%s: larger than available memory (> %d)\n", file, buflen); + //fprintf(stderr, "%s: larger than available memory (> %d)\n", file, buflen);

VIR_FORCE_FCLOSE(fp); return -1; } @@ -481,7 +610,8 @@ virtTestLogOutput(virLogSource source ATTRIBUTE_UNUSED, { struct virtTestLogData *log = data; virCheckFlags(VIR_LOG_STACK_TRACE,); - virBufferAsprintf(&log->buf, "%s: %s", timestamp, str); + if (!testOOMActive) + virBufferAsprintf(&log->buf, "%s: %s", timestamp, str); } static void @@ -550,6 +680,9 @@ int virtTestMain(int argc, int ret; bool abs_srcdir_cleanup = false; char *testRange = NULL; +#ifdef TEST_OOM + char *oomstr; +#endif abs_srcdir = getenv("abs_srcdir"); if (!abs_srcdir) { @@ -610,6 +743,56 @@ int virtTestMain(int argc, } } +#ifdef TEST_OOM + if ((oomstr = getenv("VIR_TEST_OOM")) != NULL) { + char *next; + if (testDebug == -1) + testDebug = 1; + testOOM = 1; + if (oomstr[0] != '\0' && + oomstr[1] == ':') { + if (virStrToLong_ui(oomstr + 2, &next, 10, &testOOMStart) < 0) { + fprintf(stderr, "Cannot parse range %s\n", oomstr); + return EXIT_FAILURE; + } + if (*next != '-') { + fprintf(stderr, "Cannot parse range %s\n", oomstr); + return EXIT_FAILURE; + }