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| author | Anton Blanchard <anton@samba.org> | 2010-08-25 11:32:38 +1000 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-08-25 13:08:48 +0200 |
| commit | 151772dbfad4dbe81721e40f9b3d588ea77bb7aa (patch) | |
| tree | fea47f977d73063843d0e91e2a139c4f3fb71d6c /kernel/trace/trace_stack.c | |
| parent | 502adf5778f4151dcba3f64dd6ed322151f3712c (diff) | |
| download | lwn-151772dbfad4dbe81721e40f9b3d588ea77bb7aa.tar.gz lwn-151772dbfad4dbe81721e40f9b3d588ea77bb7aa.zip | |
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>
Diffstat (limited to 'kernel/trace/trace_stack.c')
| -rw-r--r-- | kernel/trace/trace_stack.c | 2 |
1 files changed, 1 insertions, 1 deletions
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) |