Re: [PATCH] USB: gadget: f_mass_storage: fix in fsg_common_init()error recovery

From: MichaÅ Nazarewicz
Date: Wed May 12 2010 - 06:33:42 EST


On Wed, 12 May 2010 12:06:11 +0200, Viral Mehta <Viral.Mehta@xxxxxxxxxxxxxxx> wrote:
In fsg_common_release(), we are freeing common->luns.
2894 kfree(common->luns);

However, these gets allocd in fsg_common_init()
2712 /* Create the LUNs, open their backing files, and register the
2713 * LUN devices in sysfs. */
2714 curlun = kzalloc(nluns * sizeof *curlun, GFP_KERNEL);
2715 if (!curlun) {
2716 kfree(common);
2717 return ERR_PTR(-ENOMEM);
2718 }

Now, if this kzalloc at line 2714 failed
And if your patch is applied, you will follow error_release path which in
turn will call kfree on a pointer whose allocation is failed.

If luns allocation fails, common->luns will be NULL and freeing a NULL
pointer is a no-operation thus the code works just fine.

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