Readding the list. On 14.10.19 11:36, Lange Norbert wrote: >> -----Original Message----- >> From: Xenomai <xenomai-boun...@xenomai.org> On Behalf Of Jan Kiszka >> via Xenomai >> Sent: Montag, 14. Oktober 2019 08:26 >> To: Norbert Lange <nolang...@gmail.com>; Xenomai >> <xenomai@xenomai.org> >> Subject: Re: running xenomai through scan-build or: some 100 issues with >> static code analysis >> >> NON-ANDRITZ SOURCE: BE CAUTIOUS WITH CONTENT, LINKS OR >> ATTACHMENTS. >> >> >> On 13.10.19 21:49, Norbert Lange via Xenomai wrote: >>> Hello, >>> >>> I did run some static analysis tools over xenomai 3.1rc2 userspace >>> libraries, and there seems to be alot of real issues. >>> >>> The tools are clangs builtin statical analysis and clang-tidy, >>> naturally there is some overlap in the reports. >>> clang-tidy would need to be configured to fit Xenomai's practices >>> (there is a ton of configurable checks), so this is more of an example. >>> The other, clang's statical analysis is more relevant as there are >>> very few false positives. >>> >>> Additionally to the checks, there is a directory failures, files that >>> cant be built with clang. Even if no one ships Xenomai built by that >>> compiler, fixing those should help, for being able to run those tools >>> and several IDE's and Editors already use clangd for code competition etc. >>> >>> I'd hope that such reports could be incorporated into the CI builds. >>> running the analysis on cross-builds is alot more daunting, but on >>> native builds its rather easy. >> >> This is generally a valuable thing. Unfortunately, it starts with some more >> work: modelling of functions and syscalls that clang has no insight into and, >> thus, throws false-positives around them. Quickly browsing through the >> report, I only saw one real finding so far, and that was a harmless "assigned >> but never used" warning. But I'm sure that there are a few more severe >> issues in that haystack. > > Did you look only at the tidy-report? The other, website based report has > tons of valid issues, > and clang models POSIX/GNU functions - that’s enough for most of the code.
No, I didn't look at the tidy reports, the other ones instead. And a lot of those I checked (might not have been representative) stumbled over the unknown behavior of Xenomai systems - naturally. Some may have also stumbled over missing noreturn annotations. Others simply because the graph didn't get that a path was not taken with the assumed input values. All normal for static analysis. > > eg.: > > utils/analogy/calibration_ni_m.c: use after free (your error() macro is > broken). A nice example for improper modeling of clang: error[_at_line] will never return when passed a non-zero status. The error macro is still wrong because it assumes that this will only happen for status < 0. > lib/copperplate/heapobj-heapmem.c: heapobj_init_array_private with size=0 has > undefined behavior > > Every report I looked at seemed valid, those that are questionable, like > heapobj_init_array_private > Are questionable because it's not clear if this function is allowed to be > called with size=0. > Means it's questionable for everyone reading the code, and something an > analyzer should throw up. > Its either a bug or some annotation would help (__builtin_expect(size != 0, > 1) or assert(size != 0)). > This one indeed requires a closer look and likely proper error handline for size == 0. >> >> I was already considering to enable Coverity via our CI. It generally works, >> it >> has proven to find real issues without too much modelling effort (though this >> case may be different because of all the custom syscalls), but since Synopsis >> bought it, the availability and quality of their public OSS service massively >> degraded. >> >> So, looking into clang might be a more reliable alternative. I'm open for >> patches that pave the way. For CI, we may need a more recent source than >> clang-6 because that is what Travis provides us ATM. > > I dont have any experience with travis, but can't you just tell you want a > recent Ubuntu/Debian? We cannot easily change that, there are only pre-defined Ubuntu images available. At most we can try a dist-upgrade during the test, but that may prolong the setup time too much. Jan -- Siemens AG, Corporate Technology, CT RDA IOT SES-DE Corporate Competence Center Embedded Linux
