From 151772dbfad4dbe81721e40f9b3d588ea77bb7aa Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@samba.org>
Date: Wed, 25 Aug 2010 11:32:38 +1000
Subject: [PATCH 1/2] tracing/trace_stack: Fix stack trace on ppc64
save_stack_trace() stores the instruction pointer, not the
function descriptor. On ppc64 the trace stack code currently
dereferences the instruction pointer and shows 8 bytes of
instructions in our backtraces:
# cat /sys/kernel/debug/tracing/stack_trace
Depth Size Location (26 entries)
----- ---- --------
0) 5424 112 0x6000000048000004
1) 5312 160 0x60000000ebad01b0
2) 5152 160 0x2c23000041c20030
3) 4992 240 0x600000007c781b79
4) 4752 160 0xe84100284800000c
5) 4592 192 0x600000002fa30000
6) 4400 256 0x7f1800347b7407e0
7) 4144 208 0xe89f0108f87f0070
8) 3936 272 0xe84100282fa30000
Since we aren't dealing with function descriptors, use %pS
instead of %pF to fix it:
# cat /sys/kernel/debug/tracing/stack_trace
Depth Size Location (26 entries)
----- ---- --------
0) 5424 112 ftrace_call+0x4/0x8
1) 5312 160 .current_io_context+0x28/0x74
2) 5152 160 .get_io_context+0x48/0xa0
3) 4992 240 .cfq_set_request+0x94/0x4c4
4) 4752 160 .elv_set_request+0x60/0x84
5) 4592 192 .get_request+0x2d4/0x468
6) 4400 256 .get_request_wait+0x7c/0x258
7) 4144 208 .__make_request+0x49c/0x610
8) 3936 272 .generic_make_request+0x390/0x434
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: rostedt@goodmis.org
Cc: fweisbec@gmail.com
LKML-Reference: <20100825013238.GE28360@kryten>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/trace/trace_stack.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 056468eae7cf..a6b7e0e0f3eb 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -249,7 +249,7 @@ static int trace_lookup_stack(struct seq_file *m, long i)
{
unsigned long addr = stack_dump_trace[i];
- return seq_printf(m, "%pF\n", (void *)addr);
+ return seq_printf(m, "%pS\n", (void *)addr);
}
static void print_disabled(struct seq_file *m)
From 8d330919927ea31fa083b5a80084dc991da813a0 Mon Sep 17 00:00:00 2001
From: Lin Ming <ming.m.lin@intel.com>
Date: Wed, 25 Aug 2010 21:06:32 +0000
Subject: [PATCH 2/2] perf, x86, Pentium4: Clear the P4_CCCR_FORCE_OVF flag
If on Pentium4 CPUs the FORCE_OVF flag is set then an NMI happens
on every event, which can generate a flood of NMIs. Clear it.
Reported-by: Vince Weaver <vweaver1@eecs.utk.edu>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/cpu/perf_event_p4.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index febb12cea795..7e578e9cc58b 100644
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -497,6 +497,8 @@ static int p4_hw_config(struct perf_event *event)
event->hw.config |= event->attr.config &
(p4_config_pack_escr(P4_ESCR_MASK_HT) |
p4_config_pack_cccr(P4_CCCR_MASK_HT | P4_CCCR_RESERVED));
+
+ event->hw.config &= ~P4_CCCR_FORCE_OVF;
}
rc = x86_setup_perfctr(event);