Messages in this thread Patch in this message |  | | | Date | Thu, 14 May 2009 15:32:47 -0700 | | From | Greg KH <> | | Subject | [patch 12/51] Fix for enabling branch profiling makes sparse unusable |
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2.6.29-stable review patch. If anyone has any objections, please let us know.
------------------ From: Bart Van Assche <bart.vanassche@gmail.com>
commit d9ad8bc0ca823705413f75b50c442a88cc518b35 upstream.
One of the changes between kernels 2.6.28 and 2.6.29 is that a branch profiler has been added for if() statements. Unfortunately this patch makes the sparse output unusable with CONFIG_TRACE_BRANCH_PROFILING=y: when branch profiling is enabled, sparse prints so much false positives that the real issues are no longer visible. This behavior can be reproduced as follows: * enable CONFIG_TRACE_BRANCH_PROFILING, e.g. by running make allyesconfig or make allmodconfig. * run make C=2 Result: a huge number of the following sparse warnings. ... include/linux/cpumask.h:547:2: warning: symbol '______r' shadows an earlier one include/linux/cpumask.h:547:2: originally declared here ... The patch below fixes this by disabling branch profiling while analyzing the kernel code with sparse.
This patch is already included in 2.6.30-rc1 -- see also http://lkml.org/lkml/2009/4/5/120.
Signed-off-by: Bart Van Assche <bart.vanassche@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <200904051620.02311.bart.vanassche@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- include/linux/compiler.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -75,7 +75,8 @@ struct ftrace_branch_data { * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code * to disable branch tracing on a per file basis. */ -#if defined(CONFIG_TRACE_BRANCH_PROFILING) && !defined(DISABLE_BRANCH_PROFILING) +#if defined(CONFIG_TRACE_BRANCH_PROFILING) \ + && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__) void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); #define likely_notrace(x) __builtin_expect(!!(x), 1)
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