[PATCH] Correct misc_register return code handling in several drivers

Clean up several code points in which the return code from misc_register is
not handled properly.

Several modules failed to deregister various hooks when misc_register fails,
and this patch cleans them up.  Also there are a few modules that legitimately
don't care about the failure status of misc register.  These drivers however
unilaterally call misc_deregister on module unload.

Since misc_register doesn't initialize the list_head in the init_routine if it
fails, the deregister operation is at risk for oopsing when list_del is
called.  The initial solution was to manually init the list in the miscdev
structure in each of those modules, but the consensus in this thread was to
consolodate and do that universally inside misc_register.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Kylene Jo Hall <kjhall@us.ibm.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Olaf Hering <olh@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 7a484fc7cb9eae84d0a3b04e82f18c6e7e263955..7e975f606924e04b6d24eef36707cbc97723cebc 100644 (file)
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -199,6 +199,8 @@ int misc_register(struct miscdevice * misc)
        dev_t dev;
        int err = 0;
 
+       INIT_LIST_HEAD(&misc->list);
+
        down(&misc_sem);
        list_for_each_entry(c, &misc_list, list) {
                if (c->minor == misc->minor) {

diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index 22b9905c1e526f7521c0b70a143c766c1e0f534c..c09160383a5332c9635c4813215dabd9063bade8 100644 (file)
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -680,7 +680,7 @@ static int __init mmtimer_init(void)
        if (sn_rtc_cycles_per_second < 100000) {
                printk(KERN_ERR "%s: unable to determine clock frequency\n",
                       MMTIMER_NAME);
-               return -1;
+               goto out1;
        }
 
        mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
@@ -689,13 +689,13 @@ static int __init mmtimer_init(void)
        if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {
                printk(KERN_WARNING "%s: unable to allocate interrupt.",
                        MMTIMER_NAME);
-               return -1;
+               goto out1;
        }
 
        if (misc_register(&mmtimer_miscdev)) {
                printk(KERN_ERR "%s: failed to register device\n",
                       MMTIMER_NAME);
-               return -1;
+               goto out2;
        }
 
        /* Get max numbered node, calculate slots needed */
@@ -709,16 +709,18 @@ static int __init mmtimer_init(void)
        if (timers == NULL) {
                printk(KERN_ERR "%s: failed to allocate memory for device\n",
                                MMTIMER_NAME);
-               return -1;
+               goto out3;
        }
 
+       memset(timers,0,(sizeof(mmtimer_t *)*maxn));
+
        /* Allocate mmtimer_t's for each online node */
        for_each_online_node(node) {
                timers[node] = kmalloc_node(sizeof(mmtimer_t)*NUM_COMPARATORS, GFP_KERNEL, node);
                if (timers[node] == NULL) {
                        printk(KERN_ERR "%s: failed to allocate memory for device\n",
                                MMTIMER_NAME);
-                       return -1;
+                       goto out4;
                }
                for (i=0; i< NUM_COMPARATORS; i++) {
                        mmtimer_t * base = timers[node] + i;
@@ -739,6 +741,17 @@ static int __init mmtimer_init(void)
               sn_rtc_cycles_per_second/(unsigned long)1E6);
 
        return 0;
+
+out4:
+       for_each_online_node(node) {
+               kfree(timers[node]);
+       }
+out3:
+       misc_deregister(&mmtimer_miscdev);
+out2:
+       free_irq(SGI_MMTIMER_VECTOR, NULL);
+out1:
+       return -1;
 }
 
 module_init(mmtimer_init);

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 774fa861169ad5af8392639178366db761356679..33e1f66e39cb62550a762724b8dcbfd4d7d5326b 100644 (file)
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -1155,6 +1155,7 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
 
        if (sysfs_create_group(&dev->kobj, chip->vendor.attr_group)) {
                list_del(&chip->list);
+               misc_deregister(&chip->vendor.miscdev);
                put_device(dev);
                clear_bit(chip->dev_num, dev_mask);
                kfree(chip);

diff --git a/drivers/input/misc/hp_sdc_rtc.c b/drivers/input/misc/hp_sdc_rtc.c
index ab4da79ee560d9279afc989d129715c45dd1593c..31d5a13bfd6bb3a534b11918676fda5fb06112fe 100644 (file)
--- a/drivers/input/misc/hp_sdc_rtc.c
+++ b/drivers/input/misc/hp_sdc_rtc.c
@@ -695,7 +695,9 @@ static int __init hp_sdc_rtc_init(void)
 
        if ((ret = hp_sdc_request_timer_irq(&hp_sdc_rtc_isr)))
                return ret;
-       misc_register(&hp_sdc_rtc_dev);
+       if (misc_register(&hp_sdc_rtc_dev) != 0)
+               printk(KERN_INFO "Could not register misc. dev for i8042 rtc\n");
+
         create_proc_read_entry ("driver/rtc", 0, NULL,
                                hp_sdc_rtc_read_proc, NULL);
 

diff --git a/drivers/macintosh/apm_emu.c b/drivers/macintosh/apm_emu.c
index 1293876a2ebd3c60244ae12c7ceb05bf630b315f..8862a83b8d8480451453fc7e6625350ce7f46cb2 100644 (file)
--- a/drivers/macintosh/apm_emu.c
+++ b/drivers/macintosh/apm_emu.c
@@ -529,7 +529,8 @@ static int __init apm_emu_init(void)
        if (apm_proc)
                apm_proc->owner = THIS_MODULE;
 
-       misc_register(&apm_device);
+       if (misc_register(&apm_device) != 0)
+               printk(KERN_INFO "Could not create misc. device for apm\n");
 
        pmu_register_sleep_notifier(&apm_sleep_notifier);