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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2016-12-07 14:31:33 +0100
committerThomas Gleixner <tglx@linutronix.de>2016-12-07 14:36:21 +0100
commitb18cc3de00ec3442cf40ac60787dbe0703b99e24 (patch)
tree70db9244d8ecf7126726510af587e65b4eae4574 /kernel/trace/ring_buffer.c
parent1f759d328f6d8c06b5db55374b028565187deaca (diff)
downloadlwn-b18cc3de00ec3442cf40ac60787dbe0703b99e24.tar.gz
lwn-b18cc3de00ec3442cf40ac60787dbe0703b99e24.zip
tracing/rb: Init the CPU mask on allocation
Before commit b32614c03413 ("tracing/rb: Convert to hotplug state machine") the allocated cpumask was initialized to the mask of online or possible CPUs. After the CPU hotplug changes the buffer initialization moved to trace_rb_cpu_prepare() but the cpumask is allocated with alloc_cpumask() and therefor has random content. As a consequence the cpu buffers are not initialized and a later access dereferences a NULL pointer. Use zalloc_cpumask() instead so trace_rb_cpu_prepare() initializes the buffers properly. Fixes: b32614c03413 ("tracing/rb: Convert to hotplug state machine") Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/20161207133133.hzkcqfllxcdi3joz@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace/ring_buffer.c')
-rw-r--r--kernel/trace/ring_buffer.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index a7a055f167c7..89a2611a1635 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1297,7 +1297,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
if (!buffer)
return NULL;
- if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
+ if (!zalloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
goto fail_free_buffer;
nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);