2 small patches sent out for review.
-Robert
Robert Richter (2):
oprofile, s390: Fix uninitialized memory access when writing to
oprofilefs
oprofile: Remove 'WQ on CPUx, prefer CPUy' warning
arch/s390/oprofile/init.c | 10 +++++-----
drivers/oprofile/cpu_buffer.c | 11 +++--------
2 files changed, 8 insertions(+), 13 deletions(-)
--
1.7.8.6
Under certain workloads we see the following warnings:
WQ on CPU0, prefer CPU1
WQ on CPU0, prefer CPU2
WQ on CPU0, prefer CPU3
It warns the user that the wq to access a per-cpu buffers runs not on
the same cpu. This happens if the wq is rescheduled on a different cpu
than where the buffer is located. This was probably implemented to
detect performance issues. Not sure if there actually is one as the
buffers are copied to a single buffer anyway which should be the
actual bottleneck.
We wont change WQ implementation. Since a user can do nothing the
warning is pointless. Removing it.
Cc: Andi Kleen <[email protected]>
Signed-off-by: Robert Richter <[email protected]>
---
drivers/oprofile/cpu_buffer.c | 11 +++--------
1 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index b8ef8dd..8aa73fa 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -451,14 +451,9 @@ static void wq_sync_buffer(struct work_struct *work)
{
struct oprofile_cpu_buffer *b =
container_of(work, struct oprofile_cpu_buffer, work.work);
- if (b->cpu != smp_processor_id()) {
- printk(KERN_DEBUG "WQ on CPU%d, prefer CPU%d\n",
- smp_processor_id(), b->cpu);
-
- if (!cpu_online(b->cpu)) {
- cancel_delayed_work(&b->work);
- return;
- }
+ if (b->cpu != smp_processor_id() && !cpu_online(b->cpu)) {
+ cancel_delayed_work(&b->work);
+ return;
}
sync_buffer(b->cpu);
--
1.7.8.6
If oprofilefs_ulong_from_user() is called with count equals zero, *val
remains unchanged. Depending on the implementation it might be
uninitialized. Fixing users of oprofilefs_ulong_ from_user().
We missed these s390 changes with:
913050b oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
Cc: [email protected] # 3.3+
Signed-off-by: Robert Richter <[email protected]>
---
arch/s390/oprofile/init.c | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/s390/oprofile/init.c b/arch/s390/oprofile/init.c
index a1e9d69..584b936 100644
--- a/arch/s390/oprofile/init.c
+++ b/arch/s390/oprofile/init.c
@@ -169,7 +169,7 @@ static ssize_t hw_interval_write(struct file *file, char const __user *buf,
if (*offset)
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
- if (retval)
+ if (retval <= 0)
return retval;
if (val < oprofile_min_interval)
oprofile_hw_interval = oprofile_min_interval;
@@ -212,7 +212,7 @@ static ssize_t hwsampler_zero_write(struct file *file, char const __user *buf,
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
- if (retval)
+ if (retval <= 0)
return retval;
if (val != 0)
return -EINVAL;
@@ -243,7 +243,7 @@ static ssize_t hwsampler_kernel_write(struct file *file, char const __user *buf,
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
- if (retval)
+ if (retval <= 0)
return retval;
if (val != 0 && val != 1)
@@ -278,7 +278,7 @@ static ssize_t hwsampler_user_write(struct file *file, char const __user *buf,
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
- if (retval)
+ if (retval <= 0)
return retval;
if (val != 0 && val != 1)
@@ -317,7 +317,7 @@ static ssize_t timer_enabled_write(struct file *file, char const __user *buf,
return -EINVAL;
retval = oprofilefs_ulong_from_user(&val, buf, count);
- if (retval)
+ if (retval <= 0)
return retval;
if (val != 0 && val != 1)
--
1.7.8.6
On Fri, Aug 24, 2012 at 08:53:31PM +0200, Robert Richter wrote:
> Under certain workloads we see the following warnings:
>
> WQ on CPU0, prefer CPU1
> WQ on CPU0, prefer CPU2
> WQ on CPU0, prefer CPU3
>
> It warns the user that the wq to access a per-cpu buffers runs not on
> the same cpu. This happens if the wq is rescheduled on a different cpu
> than where the buffer is located. This was probably implemented to
> detect performance issues. Not sure if there actually is one as the
> buffers are copied to a single buffer anyway which should be the
> actual bottleneck.
>
> We wont change WQ implementation. Since a user can do nothing the
> warning is pointless. Removing it.
Looks good to me.
Acked-by: Andi Kleen <[email protected]>
-Andi