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mm: bdi: fix race in bdi_class device creation
There is a race from when a device is created with device_create() and then the drvdata is set with a call to dev_set_drvdata() in which a sysfs file could be open, yet the drvdata will be NULL, causing all sorts of bad things to happen. This patch fixes the problem by using the new function, device_create_vargs(). Many thanks to Arthur Jones <ajones@riverbed.com> for reporting the bug, and testing patches out. Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Arthur Jones <ajones@riverbed.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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parent
8882b39421
commit
19051c5035
1 changed files with 2 additions and 10 deletions
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@ -172,30 +172,22 @@ postcore_initcall(bdi_class_init);
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int bdi_register(struct backing_dev_info *bdi, struct device *parent,
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const char *fmt, ...)
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{
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char *name;
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va_list args;
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int ret = 0;
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struct device *dev;
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va_start(args, fmt);
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name = kvasprintf(GFP_KERNEL, fmt, args);
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dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
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va_end(args);
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if (!name)
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return -ENOMEM;
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dev = device_create(bdi_class, parent, MKDEV(0, 0), name);
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if (IS_ERR(dev)) {
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ret = PTR_ERR(dev);
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goto exit;
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}
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bdi->dev = dev;
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dev_set_drvdata(bdi->dev, bdi);
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bdi_debug_register(bdi, name);
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bdi_debug_register(bdi, dev_name(dev));
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exit:
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kfree(name);
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return ret;
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}
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EXPORT_SYMBOL(bdi_register);
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