summaryrefslogtreecommitdiff
path: root/tools/testing/selftests/bpf/test_progs.c
diff options
context:
space:
mode:
authorAndrii Nakryiko <andriin@fb.com>2020-02-25 03:08:47 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2020-02-26 00:43:02 +0300
commit9fb156bb82a33f01708fbbb8828836a4219efc3d (patch)
tree24fd43ddb77218730ed80f56a87ff40a9913eccc /tools/testing/selftests/bpf/test_progs.c
parente0360423d0204eb22f97ed89ba56da496bb9a094 (diff)
downloadlinux-9fb156bb82a33f01708fbbb8828836a4219efc3d.tar.xz
selftests/bpf: Print backtrace on SIGSEGV in test_progs
Due to various bugs in tests clean up code (usually), if host system is misconfigured, it happens that test_progs will just crash in the middle of running a test with little to no indication of where and why the crash happened. For cases where coredump is not readily available (e.g., inside a CI), it's very helpful to have a stack trace, which lead to crash, to be printed out. This change adds a signal handler that will capture and print out symbolized backtrace: $ sudo ./test_progs -t mmap test_mmap:PASS:skel_open_and_load 0 nsec test_mmap:PASS:bss_mmap 0 nsec test_mmap:PASS:data_mmap 0 nsec Caught signal #11! Stack trace: ./test_progs(crash_handler+0x18)[0x42a888] /lib64/libpthread.so.0(+0xf5d0)[0x7f2aab5175d0] ./test_progs(test_mmap+0x3c0)[0x41f0a0] ./test_progs(main+0x160)[0x407d10] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7f2aab15d3d5] ./test_progs[0x407ebc] [1] 1988412 segmentation fault (core dumped) sudo ./test_progs -t mmap Unfortunately, glibc's symbolization support is unable to symbolize static functions, only global ones will be present in stack trace. But it's still a step forward without adding extra libraries to get a better symbolization. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200225000847.3965188-1-andriin@fb.com
Diffstat (limited to 'tools/testing/selftests/bpf/test_progs.c')
-rw-r--r--tools/testing/selftests/bpf/test_progs.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index bab1e6f1d8f1..a969c77e9456 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -6,6 +6,8 @@
#include "bpf_rlimit.h"
#include <argp.h>
#include <string.h>
+#include <signal.h>
+#include <execinfo.h> /* backtrace */
/* defined in test_progs.h */
struct test_env env = {};
@@ -617,6 +619,23 @@ int cd_flavor_subdir(const char *exec_name)
return chdir(flavor);
}
+#define MAX_BACKTRACE_SZ 128
+void crash_handler(int signum)
+{
+ void *bt[MAX_BACKTRACE_SZ];
+ size_t sz;
+
+ sz = backtrace(bt, ARRAY_SIZE(bt));
+
+ if (env.test)
+ dump_test_log(env.test, true);
+ if (env.stdout)
+ stdio_restore();
+
+ fprintf(stderr, "Caught signal #%d!\nStack trace:\n", signum);
+ backtrace_symbols_fd(bt, sz, STDERR_FILENO);
+}
+
int main(int argc, char **argv)
{
static const struct argp argp = {
@@ -624,8 +643,14 @@ int main(int argc, char **argv)
.parser = parse_arg,
.doc = argp_program_doc,
};
+ struct sigaction sigact = {
+ .sa_handler = crash_handler,
+ .sa_flags = SA_RESETHAND,
+ };
int err, i;
+ sigaction(SIGSEGV, &sigact, NULL);
+
err = argp_parse(&argp, argc, argv, 0, NULL, &env);
if (err)
return err;