Re: [PATCH] perf_counter/powerpc: Check oprofile_cpu_type for NULL before using it

Re: [PATCH] perf_counter/powerpc: Check oprofile_cpu_type for NULL before using it

[Ingo Molnar]

* Paul Mackerras <paulus@samba.org> wrote:

> From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> If the current CPU doesn't support performance counters,
> cur_cpu_spec->oprofile_cpu_type can be NULL.  The current perf_counter
> modules don't test for that case and would thus crash at boot time.
> 
> Bug reported by David Woodhouse.
> 
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Reported-by: David Woodhouse <dwmw2@infradead.org>
> Signed-off-by: Paul Mackerras <paulus@samba.org>
> ---
> Ingo, this needs to go in for .31 since it fixes a boot-time oops.
> Are you going to be sending a batch to Linus shortly or should I send
> this to him separately?

Yeah, wanted to send a batch of fixes later today - so i've queued 
this one up too in perfcounters/urgent.

Thanks,

	Ingo

[tip:perfcounters/urgent] perf_counter/powerpc: Check oprofile_cpu_type for NULL before using it

[tip-bot for Benjamin Herrenschmidt]

Commit-ID:  e0d82a0a4e9841b787e6431ccfbb515546c55dc2
Gitweb:     http://git.kernel.org/tip/e0d82a0a4e9841b787e6431ccfbb515546c55dc2
Author:     Benjamin Herrenschmidt <benh@kernel.crashing.org>
AuthorDate: Thu, 6 Aug 2009 21:16:44 +1000
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 6 Aug 2009 13:55:09 +0200

perf_counter/powerpc: Check oprofile_cpu_type for NULL before using it

If the current CPU doesn't support performance counters,
cur_cpu_spec->oprofile_cpu_type can be NULL. The current
perf_counter modules don't test for that case and would thus
crash at boot time.

Bug reported by David Woodhouse.

Reported-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Paul Mackerras <paulus@samba.org>
LKML-Reference: <19066.48028.446975.501454@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 arch/powerpc/kernel/mpc7450-pmu.c |    3 ++-
 arch/powerpc/kernel/power4-pmu.c  |    3 ++-
 arch/powerpc/kernel/power5+-pmu.c |    5 +++--
 arch/powerpc/kernel/power5-pmu.c  |    3 ++-
 arch/powerpc/kernel/power6-pmu.c  |    3 ++-
 arch/powerpc/kernel/power7-pmu.c  |    3 ++-
 arch/powerpc/kernel/ppc970-pmu.c  |    5 +++--
 7 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/kernel/mpc7450-pmu.c b/arch/powerpc/kernel/mpc7450-pmu.c
index c244133..cc466d0 100644
--- a/arch/powerpc/kernel/mpc7450-pmu.c
+++ b/arch/powerpc/kernel/mpc7450-pmu.c
@@ -407,7 +407,8 @@ struct power_pmu mpc7450_pmu = {
 
 static int init_mpc7450_pmu(void)
 {
-	if (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc/7450"))
+	if (!cur_cpu_spec->oprofile_cpu_type ||
+	    strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc/7450"))
 		return -ENODEV;
 
 	return register_power_pmu(&mpc7450_pmu);
diff --git a/arch/powerpc/kernel/power4-pmu.c b/arch/powerpc/kernel/power4-pmu.c
index db90b0c..3c90a3d 100644
--- a/arch/powerpc/kernel/power4-pmu.c
+++ b/arch/powerpc/kernel/power4-pmu.c
@@ -606,7 +606,8 @@ static struct power_pmu power4_pmu = {
 
 static int init_power4_pmu(void)
 {
-	if (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power4"))
+	if (!cur_cpu_spec->oprofile_cpu_type ||
+	    strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power4"))
 		return -ENODEV;
 
 	return register_power_pmu(&power4_pmu);
diff --git a/arch/powerpc/kernel/power5+-pmu.c b/arch/powerpc/kernel/power5+-pmu.c
index f4adca8..31918af 100644
--- a/arch/powerpc/kernel/power5+-pmu.c
+++ b/arch/powerpc/kernel/power5+-pmu.c
@@ -678,8 +678,9 @@ static struct power_pmu power5p_pmu = {
 
 static int init_power5p_pmu(void)
 {
-	if (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power5+")
-	    && strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power5++"))
+	if (!cur_cpu_spec->oprofile_cpu_type ||
+	    (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power5+")
+	     && strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power5++")))
 		return -ENODEV;
 
 	return register_power_pmu(&power5p_pmu);
diff --git a/arch/powerpc/kernel/power5-pmu.c b/arch/powerpc/kernel/power5-pmu.c
index 29b2c6c..867f6f6 100644
--- a/arch/powerpc/kernel/power5-pmu.c
+++ b/arch/powerpc/kernel/power5-pmu.c
@@ -618,7 +618,8 @@ static struct power_pmu power5_pmu = {
 
 static int init_power5_pmu(void)
 {
-	if (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power5"))
+	if (!cur_cpu_spec->oprofile_cpu_type ||
+	    strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power5"))
 		return -ENODEV;
 
 	return register_power_pmu(&power5_pmu);
diff --git a/arch/powerpc/kernel/power6-pmu.c b/arch/powerpc/kernel/power6-pmu.c
index 09ae5bf..fa21890 100644
--- a/arch/powerpc/kernel/power6-pmu.c
+++ b/arch/powerpc/kernel/power6-pmu.c
@@ -537,7 +537,8 @@ static struct power_pmu power6_pmu = {
 
 static int init_power6_pmu(void)
 {
-	if (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power6"))
+	if (!cur_cpu_spec->oprofile_cpu_type ||
+	    strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power6"))
 		return -ENODEV;
 
 	return register_power_pmu(&power6_pmu);
diff --git a/arch/powerpc/kernel/power7-pmu.c b/arch/powerpc/kernel/power7-pmu.c
index 5a9f5cb..388cf57 100644
--- a/arch/powerpc/kernel/power7-pmu.c
+++ b/arch/powerpc/kernel/power7-pmu.c
@@ -366,7 +366,8 @@ static struct power_pmu power7_pmu = {
 
 static int init_power7_pmu(void)
 {
-	if (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power7"))
+	if (!cur_cpu_spec->oprofile_cpu_type ||
+	    strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/power7"))
 		return -ENODEV;
 
 	return register_power_pmu(&power7_pmu);
diff --git a/arch/powerpc/kernel/ppc970-pmu.c b/arch/powerpc/kernel/ppc970-pmu.c
index 833097a..75dccb7 100644
--- a/arch/powerpc/kernel/ppc970-pmu.c
+++ b/arch/powerpc/kernel/ppc970-pmu.c
@@ -488,8 +488,9 @@ static struct power_pmu ppc970_pmu = {
 
 static int init_ppc970_pmu(void)
 {
-	if (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/970")
-	    && strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/970MP"))
+	if (!cur_cpu_spec->oprofile_cpu_type ||
+	    (strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/970")
+	     && strcmp(cur_cpu_spec->oprofile_cpu_type, "ppc64/970MP")))
 		return -ENODEV;
 
 	return register_power_pmu(&ppc970_pmu);