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tracing/trace_stack: Fix stack trace on ppc64

PATCH In review Anton Blanchard 4 participants 7 messages Aug 25, 2010 – Aug 31, 2010 Tracing

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Anton Blanchard

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#0 lore raw

PATCH 1/1 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 <[email protected]>

---

kernel/trace/trace_stack.c +1 -1
Index: powerpc.git/kernel/trace/trace_stack.c
===================================================================
@@ -249,7 +249,7 @@ static int trace_lookup_stack(struct seq
 {
 	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)
author
#1 lore raw
Commit-ID:  151772dbfad4dbe81721e40f9b3d588ea77bb7aa
Gitweb:     http://git.kernel.org/tip/151772dbfad4dbe81721e40f9b3d588ea77bb7aa
Author:     Anton Blanchard <[email protected]>
AuthorDate: Wed, 25 Aug 2010 11:32:38 +1000
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 25 Aug 2010 13:08:48 +0200

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 <[email protected]>
Cc [email protected]
Cc [email protected]

LKML-Reference: <20100825013238.GE28360@kryten>

Signed-off-by Ingo Molnar <[email protected]>
---
 kernel/trace/trace_stack.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
kernel/trace/trace_stack.c +1 -1
index 056468e..a6b7e0e 100644
@@ -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)
maintainer
#2 lore raw
In reply to Anton Blanchard
Quoted 33 lines · Anton Blanchard

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
Quoted 1 line
Signed-off-by Anton Blanchard <[email protected]>

Thanks, I'll test this to make sure it doesn't break x86, and then push it into a stable/-rc patch queue.

-- Steve

Quoted 15 lines

---

Index: powerpc.git/kernel/trace/trace_stack.c
===================================================================

kernel/trace/trace_stack.c +1 -1
@@ -249,7 +249,7 @@ static int trace_lookup_stack(struct seq
 {
 	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)
#3 lore raw
Quoted 34 lines · Steven Rostedt
Quoted 33 lines · Anton Blanchard

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
Quoted 6 lines
Quoted 1 line
Signed-off-by Anton Blanchard <[email protected]>

Thanks, I'll test this to make sure it doesn't break x86, and then push it into a stable/-rc patch queue.

-- Steve

Ingo has applied it already in perf/urgent.

Thanks.

maintainer
#4 lore raw
Quoted 37 lines · Frederic Weisbecker
Quoted 36 lines · Steven Rostedt
Quoted 34 lines · Anton Blanchard

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 <[email protected]>
Quoted 7 lines
Quoted 4 lines

Thanks, I'll test this to make sure it doesn't break x86, and then push it into a stable/-rc patch queue.

-- Steve

Ingo has applied it already in perf/urgent.

Hmm, I never saw the tip-bot reply :-(

I guess it only sends to the Cc tags.

-- Steve

#5 lore raw
Quoted 7 lines · Steven Rostedt

Hmm, I never saw the tip-bot reply :-(

I guess it only sends to the Cc tags.

-- Steve

We were in the commit Cc tags but somehow they didn't make it in the email tags.

Here is the tip-bot email:

---

Commit-ID:  151772dbfad4dbe81721e40f9b3d588ea77bb7aa
Gitweb:     http://git.kernel.org/tip/151772dbfad4dbe81721e40f9b3d588ea77bb7aa
Author:     Anton Blanchard <[email protected]>
AuthorDate: Wed, 25 Aug 2010 11:32:38 +1000
Committer:  Ingo Molnar <[email protected]>
CommitDate: Wed, 25 Aug 2010 13:08:48 +0200

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 <[email protected]>
Cc [email protected]
Cc [email protected]

LKML-Reference: <20100825013238.GE28360@kryten>

Signed-off-by Ingo Molnar <[email protected]>
---
 kernel/trace/trace_stack.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
kernel/trace/trace_stack.c +1 -1
index 056468e..a6b7e0e 100644
@@ -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)

--
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#6 lore raw
Quoted 5 lines · Frederic Weisbecker
Quoted 4 lines · Steven Rostedt

Hmm, I never saw the tip-bot reply :-(

I guess it only sends to the Cc tags.

Quoted 7 lines
Quoted 3 lines

-- Steve

We were in the commit Cc tags but somehow they didn't make it in the email tags.

indeed - i forwarded this to hpa.

Ingo