# ls -li

total 0

4026532007 -r--r--r-- 1 root root 0 Sep  6 18:18 nvram

4026532067 -r--r--r-- 1 root root 0 Sep  6 18:18 rtc

4026532067 -r--r--r-- 1 root root 0 Sep  6 18:18 rtc

4026532056 -rw-r--r-- 1 root root 0 Sep  6 18:18 snd-page-alloc
kernel 2.6.22.6 on a Dell Precision 390:
# CONFIG_RTC is not set

# CONFIG_RTC_DEBUG is not set

CONFIG_GEN_RTC=y

CONFIG_GEN_RTC_X=y

CONFIG_RTC_CLASS=y

CONFIG_RTC_HCTOSYS=y

CONFIG_RTC_HCTOSYS_DEVICE="rtc0"

CONFIG_RTC_INTF_SYSFS=y

CONFIG_RTC_INTF_PROC=y

CONFIG_RTC_INTF_DEV=y

# CONFIG_RTC_INTF_DEV_UIE_EMUL is not set

CONFIG_RTC_DRV_CMOS=m

CONFIG_RTC_DRV_DS1307=m

CONFIG_RTC_DRV_DS1553=m

CONFIG_RTC_DRV_DS1672=m

CONFIG_RTC_DRV_DS1742=m

# CONFIG_RTC_DRV_EP93XX is not set

CONFIG_RTC_DRV_ISL1208=m

CONFIG_RTC_DRV_MAX6900=m

# CONFIG_RTC_DRV_M48T86 is not set

CONFIG_RTC_DRV_PCF8563=m

CONFIG_RTC_DRV_PCF8583=m

CONFIG_RTC_DRV_RS5C372=m

# CONFIG_RTC_DRV_SA1100 is not set

# CONFIG_RTC_DRV_TEST is not set

CONFIG_RTC_DRV_X1205=m

CONFIG_RTC_DRV_V3020=m
CONFIG_HPET_EMULATE_RTC=y
CONFIG_EFI_RTC=y

-

Next -mm has
procfs-detect-duplicate-names.patch

procfs-detect-duplicate-names-fix.patch

procfs-detect-duplicate-names-fix-fix-2.patch
which will at least tell us who the second offender is.
I have a vague memory that this is due to selecting two different types of

rtc in config.  Perhaps a Kconfig fix is needed, dunno.
-

Semes pretty clear that this must be procfs itself...

when a filesystem sees a name in a directory, it should

refuse to make another file with the same name.  And it

should *never* reuse inode numbers...
-

procfs can reject the attempt to create the file, but the bottom line

is that two different callsites are trying to create the same file.  One

of those callsites needs fixing?

-

Both of those call sites have code to handle procfs rejecting

the file creation; nothing to fix.  And anyway, there's no way

this is a *caller* bug!
The missing step seems to be that proc_register() doesn't bother

to check whether there's already an entry for that file.  Which

is what the appended *UNTESTED* patch does (it compiles though).
- Dave
--- g26.orig/fs/proc/generic.c	2007-09-18 22:08:44.000000000 -0700

+++ g26/fs/proc/generic.c	2007-09-18 22:14:07.000000000 -0700

@@ -521,10 +521,11 @@ static const struct inode_operations pro

 	.setattr	= proc_notify_change,

 };
-static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)

+static int proc_register(struct proc_dir_entry *dir, struct proc_dir_entry *dp)

 {

 	unsigned int i;

-

+	struct proc_dir_entry *de;

+

 	i = get_inode_number();

 	if (i == 0)

 		return -EAGAIN;

@@ -547,6 +548,16 @@ static int proc_register(struct proc_dir

 	}
 	spin_lock(&proc_subdir_lock);

+

+	for (de = dir->subdir; de ; de = de->next) {

+		if (de->namelen != dp->namelen)

+			continue;

+		if (!memcmp(de->name, dp->name, de->namelen)) {

+			spin_unlock(&proc_subdir_lock);

+			return -EEXIST;

+		}

+	}

+

 	dp->next = dir->subdir;

 	dp->parent = dir;

 	dir->subdir = dp;
-