From 81ff3478d9ba7f0b48b0abef740e542fd83adf79 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Thu, 19 Jul 2012 18:28:26 +0200 Subject: [PATCH 1/2] oprofile, s390: Fix uninitialized memory access when writing to oprofilefs 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: stable@vger.kernel.org # 3.3+ Signed-off-by: Robert Richter --- arch/s390/oprofile/init.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/s390/oprofile/init.c b/arch/s390/oprofile/init.c index a1e9d69a9c90..584b93674ea4 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) From 61bccf191fe2d55b8d003b4ea3f94913745aaefa Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Wed, 22 Aug 2012 09:23:51 +0200 Subject: [PATCH 2/2] oprofile: Remove 'WQ on CPUx, prefer CPUy' warning 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 Signed-off-by: Robert Richter --- drivers/oprofile/cpu_buffer.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c index b8ef8ddcc292..8aa73fac6ad4 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);