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Re: BUG: GCC-4.4.x changes the function frame on some functions
- From: Steven Rostedt <rostedt at goodmis dot org>
- To: Andrew Haley <aph at redhat dot com>
- Cc: Thomas Gleixner <tglx at linutronix dot de>, Ingo Molnar <mingo at elte dot hu>, "H. Peter Anvin" <hpa at zytor dot com>, LKML <linux-kernel at vger dot kernel dot org>, Andrew Morton <akpm at linux-foundation dot org>, Heiko Carstens <heiko dot carstens at de dot ibm dot com>, feng dot tang at intel dot com, Fr??d??ric Weisbecker <fweisbec at gmail dot com>, Peter Zijlstra <peterz at infradead dot org>, jakub at redhat dot com, gcc at gcc dot gnu dot org
- Date: Thu, 19 Nov 2009 11:12:32 -0500
- Subject: Re: BUG: GCC-4.4.x changes the function frame on some functions
- References: <alpine.LFD.2.00.0911181933540.24119@localhost.localdomain> <tip-887a29f59b93cf54e21814869a4ab6e80b6fa623@git.kernel.org> <20091119072040.GA23579@elte.hu> <alpine.LFD.2.00.0911191053390.24119@localhost.localdomain> <alpine.LFD.2.00.0911191423190.24119@localhost.localdomain> <alpine.LFD.2.00.0911191607440.24119@localhost.localdomain> <4B0567E0.5080803@redhat.com>
- Reply-to: rostedt at goodmis dot org
On Thu, 2009-11-19 at 15:44 +0000, Andrew Haley wrote:
> We're aligning the stack properly, as per the ABI requirements. Can't
> you just fix the tracer?
Unfortunately, this is the only fix we have:
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index b416512..cd39064 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -143,7 +143,6 @@ config FUNCTION_GRAPH_TRACER
bool "Kernel Function Graph Tracer"
depends on HAVE_FUNCTION_GRAPH_TRACER
depends on FUNCTION_TRACER
- depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
default y
help
Enable the kernel to trace a function at both its return
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 45e6c01..50c2251 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1070,6 +1070,11 @@ static __init int init_graph_trace(void)
{
max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
+#if defined(CONFIG_X86_32 && __GNUC__ >= 4 && __GNUC_MINOR__ >= 4)
+ pr_info("WARNING: GCC 4.4.X breaks the function graph tracer on i686.\n"
+ " The function graph tracer will be disabled.\n");
+ return -1;
+#endif
return register_tracer(&graph_trace);
}
-- Steve