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[PATCH] g_file_storage: fix obscure race condition
This patch (as575) fixes an unlikely race in the g_file_storage driver. The problem can occur only when the driver is unbound before its initialization routine has finished. I also took the opportunity to replace kmalloc/memset with kzalloc. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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3f8c03ee05
commit
a922c68732
1 changed files with 9 additions and 12 deletions
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@ -3823,12 +3823,11 @@ static int __init fsg_bind(struct usb_gadget *gadget)
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/* Create the LUNs, open their backing files, and register the
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* LUN devices in sysfs. */
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fsg->luns = kmalloc(i * sizeof(struct lun), GFP_KERNEL);
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fsg->luns = kzalloc(i * sizeof(struct lun), GFP_KERNEL);
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if (!fsg->luns) {
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rc = -ENOMEM;
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goto out;
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}
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memset(fsg->luns, 0, i * sizeof(struct lun));
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fsg->nluns = i;
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for (i = 0; i < fsg->nluns; ++i) {
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@ -3989,6 +3988,11 @@ static int __init fsg_bind(struct usb_gadget *gadget)
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mod_data.removable, mod_data.can_stall,
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mod_data.buflen);
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DBG(fsg, "I/O thread pid: %d\n", fsg->thread_task->pid);
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set_bit(REGISTERED, &fsg->atomic_bitflags);
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/* Tell the thread to start working */
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wake_up_process(fsg->thread_task);
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return 0;
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autoconf_fail:
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@ -4051,10 +4055,9 @@ static int __init fsg_alloc(void)
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{
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struct fsg_dev *fsg;
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fsg = kmalloc(sizeof *fsg, GFP_KERNEL);
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fsg = kzalloc(sizeof *fsg, GFP_KERNEL);
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if (!fsg)
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return -ENOMEM;
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memset(fsg, 0, sizeof *fsg);
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spin_lock_init(&fsg->lock);
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init_rwsem(&fsg->filesem);
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init_waitqueue_head(&fsg->thread_wqh);
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@ -4080,15 +4083,9 @@ static int __init fsg_init(void)
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if ((rc = fsg_alloc()) != 0)
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return rc;
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fsg = the_fsg;
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if ((rc = usb_gadget_register_driver(&fsg_driver)) != 0) {
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if ((rc = usb_gadget_register_driver(&fsg_driver)) != 0)
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fsg_free(fsg);
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return rc;
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}
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set_bit(REGISTERED, &fsg->atomic_bitflags);
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/* Tell the thread to start working */
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wake_up_process(fsg->thread_task);
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return 0;
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return rc;
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}
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module_init(fsg_init);
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