From 6ba8bcd457d9fc793ac9435aa2e4138f571d4ec5 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <error27@gmail.com>
Date: Mon, 24 May 2010 14:33:49 -0700
Subject: [PATCH] rtc-cmos: do dev_set_drvdata() earlier in the initialization
The bug is an oops when dev_get_drvdata() returned null in
cmos_update_irq_enable(). The call tree looks like this:
rtc_dev_ioctl()
=> rtc_update_irq_enable()
=> cmos_update_irq_enable()
It's caused by a race condition in the module initialization. It is
rtc_device_register() which makes the ioctl operations live so I moved
the call to dev_set_drvdata() before the call to rtc_device_register().
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=15963
Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Dan Carpenter <error27@gmail.com>
Tested-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: Malte Schroder <maltesch@gmx.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/rtc/rtc-cmos.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index 96e8e70fbf1e1..11b8ea29d2b76 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -719,6 +719,9 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
}
}
+ cmos_rtc.dev = dev;
+ dev_set_drvdata(dev, &cmos_rtc);
+
cmos_rtc.rtc = rtc_device_register(driver_name, dev,
&cmos_rtc_ops, THIS_MODULE);
if (IS_ERR(cmos_rtc.rtc)) {
@@ -726,8 +729,6 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
goto cleanup0;
}
- cmos_rtc.dev = dev;
- dev_set_drvdata(dev, &cmos_rtc);
rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
spin_lock_irq(&rtc_lock);
--
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