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ring-buffer: Move resize integrity check under reader lock

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While using an application that does splice on the ftrace ring
buffer at start up, I triggered an integrity check failure.

Looking into this, I discovered that resizing the buffer performs
an integrity check after the buffer is resized. This check unfortunately
is preformed after it releases the reader lock. If a reader is
reading the buffer it may cause the integrity check to trigger a
false failure.

This patch simply moves the integrity checker under the protection
of the ring buffer reader lock.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2009-12-10 23:20:52 -05:00 • committed by Steven Rostedt
parent 184210154b
commit dd7f594357
1 changed files with 4 additions and 4 deletions
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8
kernel/trace/ring_buffer.c
View file

@ -1208,9 +1208,9 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
return; return;
rb_reset_cpu(cpu_buffer); rb_reset_cpu(cpu_buffer);
spin_unlock_irq(&cpu_buffer->reader_lock);
rb_check_pages(cpu_buffer); rb_check_pages(cpu_buffer);
spin_unlock_irq(&cpu_buffer->reader_lock);
} }
static void static void
@ -1233,9 +1233,9 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
list_add_tail(&bpage->list, cpu_buffer->pages); list_add_tail(&bpage->list, cpu_buffer->pages);
} }
rb_reset_cpu(cpu_buffer); rb_reset_cpu(cpu_buffer);
spin_unlock_irq(&cpu_buffer->reader_lock);
rb_check_pages(cpu_buffer); rb_check_pages(cpu_buffer);
spin_unlock_irq(&cpu_buffer->reader_lock);
} }
/** /**