From: Michal Marek <mmarek@suse.cz>
To: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 5/8] kbuild: add fine grained build dependencies for exported symbols
Date: Fri, 4 Mar 2016 23:53:53 +0100 [thread overview]
Message-ID: <56DA1201.9010605@suse.cz> (raw)
In-Reply-To: <56DA118E.20106@suse.com>
Dne 4.3.2016 v 23:51 Michal Marek napsal(a):
> Dne 4.3.2016 v 06:40 Nicolas Pitre napsal(a):
>> +cmd_and_fixdep = \
>> + $(echo-cmd) $(cmd_$(1)); \
>> + $(ksym_dep_filter) | \
>> + scripts/basic/fixdep -e $(depfile) $@ '$(make-cmd)' \
>> + > $(dot-target).tmp; \
>> + rm -f $(depfile); \
>> + mv -f $(dot-target).tmp $(dot-target).cmd;
>
> While trying this, I got a SIGBUS from fixdep once. My theory is that
> the depfile is mmap()ed by fixdep and modified by the preprocesor run at
> the same time. I could not reproduce this so far (still trying). But if
> it's really this race, the fix would be to disable dependency generation
> in the preprocessor by passing -Wp,MD,/dev/null or somesuch. But we
> never had this problem with genksyms, which is weird. It could as well
> be that my build machine's memory is faulty :(.
Actually, genksyms does not ran in parallel. neither before nor after
this patch.
Michal
next prev parent reply other threads:[~2016-03-04 22:53 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-04 5:40 [PATCH v5 0/8] Trim unused exported kernel symbols Nicolas Pitre
2016-03-04 5:40 ` [PATCH v5 1/8] kbuild: record needed exported symbols for modules Nicolas Pitre
2016-03-04 5:40 ` [PATCH v5 2/8] allow for per-symbol configurable EXPORT_SYMBOL() Nicolas Pitre
2016-03-04 5:40 ` [PATCH v5 3/8] fixdep: accept extra dependencies on stdin Nicolas Pitre
2016-03-04 5:40 ` [PATCH v5 4/8] kbuild: de-duplicate fixdep usage Nicolas Pitre
2016-03-04 5:40 ` [PATCH v5 5/8] kbuild: add fine grained build dependencies for exported symbols Nicolas Pitre
2016-03-04 22:51 ` Michal Marek
2016-03-04 22:53 ` Michal Marek [this message]
2016-03-05 7:12 ` Michal Marek
2016-03-06 2:33 ` Nicolas Pitre
2016-03-06 6:20 ` Nicolas Pitre
2016-03-04 5:40 ` [PATCH v5 6/8] create/adjust generated/autoksyms.h Nicolas Pitre
2016-03-04 5:40 ` [PATCH v5 7/8] kbuild: build sample modules along with the rest of the kernel Nicolas Pitre
2016-03-04 5:40 ` [PATCH v5 8/8] kconfig option for TRIM_UNUSED_KSYMS Nicolas Pitre
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