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[PATCH] g_file_storage: fix obscure race condition

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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>
This commit is contained in:
Alan Stern 2005-10-06 16:38:45 -04:00 committed by Greg Kroah-Hartman
parent 3f8c03ee05
commit a922c68732
1 changed files with 9 additions and 12 deletions
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19
drivers/usb/gadget/file_storage.c
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@ -3823,12 +3823,11 @@ static int __init fsg_bind(struct usb_gadget *gadget)
/* Create the LUNs, open their backing files, and register the
* LUN devices in sysfs. */
fsg->luns = kmalloc(i * sizeof(struct lun), GFP_KERNEL);
fsg->luns = kzalloc(i * sizeof(struct lun), GFP_KERNEL);
if (!fsg->luns) {
rc = -ENOMEM;
goto out;
}
memset(fsg->luns, 0, i * sizeof(struct lun));
fsg->nluns = i;
for (i = 0; i < fsg->nluns; ++i) {
@ -3989,6 +3988,11 @@ static int __init fsg_bind(struct usb_gadget *gadget)
mod_data.removable, mod_data.can_stall,
mod_data.buflen);
DBG(fsg, "I/O thread pid: %d\n", fsg->thread_task->pid);
set_bit(REGISTERED, &fsg->atomic_bitflags);
/* Tell the thread to start working */
wake_up_process(fsg->thread_task);
return 0;
autoconf_fail:
@ -4051,10 +4055,9 @@ static int __init fsg_alloc(void)
{
struct fsg_dev *fsg;
fsg = kmalloc(sizeof *fsg, GFP_KERNEL);
fsg = kzalloc(sizeof *fsg, GFP_KERNEL);
if (!fsg)
return -ENOMEM;
memset(fsg, 0, sizeof *fsg);
spin_lock_init(&fsg->lock);
init_rwsem(&fsg->filesem);
init_waitqueue_head(&fsg->thread_wqh);
@ -4080,15 +4083,9 @@ static int __init fsg_init(void)
if ((rc = fsg_alloc()) != 0)
return rc;
fsg = the_fsg;
if ((rc = usb_gadget_register_driver(&fsg_driver)) != 0) {
if ((rc = usb_gadget_register_driver(&fsg_driver)) != 0)
fsg_free(fsg);
return rc;
}
set_bit(REGISTERED, &fsg->atomic_bitflags);
/* Tell the thread to start working */
wake_up_process(fsg->thread_task);
return 0;
}
module_init(fsg_init);