Messages in this thread | | | Date | Wed, 13 Jul 2016 08:01:55 +0800 | From | Fengguang Wu <> | Subject | Re: [PATCH net-next 3/3] bpf: avoid stack copy and use skb ctx for event output |
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Hi Daniel,
On Wed, Jul 13, 2016 at 01:45:47AM +0200, Daniel Borkmann wrote: >On 07/13/2016 01:25 AM, kbuild test robot wrote: >> Hi, >> >> [auto build test WARNING on net-next/master] >> >> url: https://github.com/0day-ci/linux/commits/Daniel-Borkmann/BPF-event-output-helper-improvements/20160713-065944 >> config: s390-allyesconfig (attached as .config) >> compiler: s390x-linux-gnu-gcc (Debian 5.3.1-8) 5.3.1 20160205 >> reproduce: >> wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross >> chmod +x ~/bin/make.cross >> # save the attached .config to linux build tree >> make.cross ARCH=s390 >> >> All warnings (new ones prefixed by >>): >> >> kernel/trace/bpf_trace.c: In function 'bpf_perf_event_output': >> kernel/trace/bpf_trace.c:284:1: warning: 'bpf_perf_event_output' uses dynamic stack allocation >> } >> ^ >> kernel/trace/bpf_trace.c: In function 'bpf_event_output': >>>> kernel/trace/bpf_trace.c:319:1: warning: 'bpf_event_output' uses dynamic stack allocation >> } >> ^ > >Hmm, searching a bit on lkml, it seems these warnings on s390 are actually mostly >harmless I believe [1][2] ... looks like they are there to find structs sitting >on stack, for example, at least that's also what the currently existing one in the >above line (bpf_trace.c +284) appears to be about.
Yes it does look so. All such warnings happen only in s390:
% g -h -o '[^ ]*config' *dynamic-stack* | sort | uniq -c | sort -nr 118 s390-allyesconfig 80 s390-allmodconfig
Let's ignore all of them on s390.
Thanks, Fengguang
> [1] http://lkml.iu.edu/hypermail/linux/kernel/1601.2/04074.html > [2] https://lkml.org/lkml/2013/6/25/42
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