Revision 8074b26f67165bf045d92e778c9c10dc5e207fc6 authored by Miklos Szeredi on 24 February 2011, 14:49:53 UTC, committed by Linus Torvalds on 24 February 2011, 16:55:01 UTC
Grab a reference to bdev before calling blkdev_get(), which expects the refcount to be already incremented and either returns success or decrements the refcount and returns an error. The bug was introduced by e525fd89 (block: make blkdev_get/put() handle exclusive access), which didn't take into account this behavior of blkdev_get(). Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 3c522ce
backtracetest.c
/*
* Simple stack backtrace regression test module
*
* (C) Copyright 2008 Intel Corporation
* Author: Arjan van de Ven <arjan@linux.intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*/
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/stacktrace.h>
static void backtrace_test_normal(void)
{
printk("Testing a backtrace from process context.\n");
printk("The following trace is a kernel self test and not a bug!\n");
dump_stack();
}
static DECLARE_COMPLETION(backtrace_work);
static void backtrace_test_irq_callback(unsigned long data)
{
dump_stack();
complete(&backtrace_work);
}
static DECLARE_TASKLET(backtrace_tasklet, &backtrace_test_irq_callback, 0);
static void backtrace_test_irq(void)
{
printk("Testing a backtrace from irq context.\n");
printk("The following trace is a kernel self test and not a bug!\n");
init_completion(&backtrace_work);
tasklet_schedule(&backtrace_tasklet);
wait_for_completion(&backtrace_work);
}
#ifdef CONFIG_STACKTRACE
static void backtrace_test_saved(void)
{
struct stack_trace trace;
unsigned long entries[8];
printk("Testing a saved backtrace.\n");
printk("The following trace is a kernel self test and not a bug!\n");
trace.nr_entries = 0;
trace.max_entries = ARRAY_SIZE(entries);
trace.entries = entries;
trace.skip = 0;
save_stack_trace(&trace);
print_stack_trace(&trace, 0);
}
#else
static void backtrace_test_saved(void)
{
printk("Saved backtrace test skipped.\n");
}
#endif
static int backtrace_regression_test(void)
{
printk("====[ backtrace testing ]===========\n");
backtrace_test_normal();
backtrace_test_irq();
backtrace_test_saved();
printk("====[ end of backtrace testing ]====\n");
return 0;
}
static void exitf(void)
{
}
module_init(backtrace_regression_test);
module_exit(exitf);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
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