Messages in this thread | | | Date | Sat, 20 Dec 2008 16:26:52 +0530 | From | Vaidyanathan Srinivasan <> | Subject | Re: [PATCH v7 4/8] sched: nominate preferred wakeup cpu |
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* Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> [2008-12-20 16:06:02]:
> * Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> [2008-12-20 15:32:28]: > > > * Andrew Morton <akpm@linux-foundation.org> [2008-12-19 20:44:55]: > > > > > On Sat, 20 Dec 2008 10:06:38 +0530 Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote: > > > > > > > > > > > > > kernel/sched.c: In function 'schedule': > > > > > kernel/sched.c:3679: warning: 'active_balance' may be used uninitialized in this function > > > > > > > > > > This warning is correct - the code is buggy. > > > > > > > > Yes this is my code bug. I did not see the warning in sched.c. Is > > > > there any build option that I need to pass in order to get -Wall > > > > effect? > > > > > > That was just with plain old kbuild: `make allmodconfig;make'. > > > > > > That warning was produced by gcc-4.0.2. If you're using something more > > > recent then gcc has regressed. > > > > This is an interesting problem. I am unable to get that warning in the > > following GCC versions even with a combination of the following > > cmdline options: -Wall -Wextra -Wuninitialized > > > > gcc version 4.1.2 20070502 > > gcc version 4.2.3 > > > > I will look for older gcc and check this out. > > I am able to get the above warning in > gcc version 3.4.6 (Debian 3.4.6-9) > with default kbuild, no additional params. > > Did not get the warning in > gcc version 4.1.3 20080623 > > Hence there has been some change in GCC that prevented the > uninitialized warning.
Related GCC bug: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=179 Claimed to have been fixed in GCC 4.4, but I don't know if we are ready to test kernel compile with GCC 4.4.
I have tested till gcc version 4.3.2 (Debian 4.3.2-1) and the bug is not fixed. I do not get the warning from sched.c.
--Vaidy
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