Patch "regulator: s5m8767: fix get_register() error handling" has been added to the 4.4-stable tree

Patch "regulator: s5m8767: fix get_register() error handling" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    regulator: s5m8767: fix get_register() error handling

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     regulator-s5m8767-fix-get_register-error-handling.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e07ff9434167981c993a26d2edbbcb8e13801dbb Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Tue, 16 Feb 2016 15:53:11 +0100
Subject: regulator: s5m8767: fix get_register() error handling

From: Arnd Bergmann <arnd@arndb.de>

commit e07ff9434167981c993a26d2edbbcb8e13801dbb upstream.

The s5m8767_pmic_probe() function calls s5m8767_get_register() to
read data without checking the return code, which produces a compile-time
warning when that data is accessed:

drivers/regulator/s5m8767.c: In function 's5m8767_pmic_probe':
drivers/regulator/s5m8767.c:924:7: error: 'enable_reg' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/regulator/s5m8767.c:944:30: error: 'enable_val' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This changes the s5m8767_get_register() function to return a -EINVAL
not just for an invalid register number but also for an invalid
regulator number, as both would result in returning uninitialized
data. The s5m8767_pmic_probe() function is then changed accordingly
to fail on a read error, as all the other callers of s5m8767_get_register()
already do.

In practice this probably cannot happen, as we don't call
s5m8767_get_register() with invalid arguments, but the gcc
warning seems valid in principle, in terms writing safe
error checking.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 9c4c60554acf ("regulator: s5m8767: Convert to use regulator_[enable|disable|is_enabled]_regmap")
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/regulator/s5m8767.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

--- a/drivers/regulator/s5m8767.c
+++ b/drivers/regulator/s5m8767.c
@@ -202,9 +202,10 @@ static int s5m8767_get_register(struct s
 		}
 	}
 
-	if (i < s5m8767->num_regulators)
-		*enable_ctrl =
-		s5m8767_opmode_reg[reg_id][mode] << S5M8767_ENCTRL_SHIFT;
+	if (i >= s5m8767->num_regulators)
+		return -EINVAL;
+
+	*enable_ctrl = s5m8767_opmode_reg[reg_id][mode] << S5M8767_ENCTRL_SHIFT;
 
 	return 0;
 }
@@ -937,8 +938,12 @@ static int s5m8767_pmic_probe(struct pla
 			else
 				regulators[id].vsel_mask = 0xff;
 
-			s5m8767_get_register(s5m8767, id, &enable_reg,
+			ret = s5m8767_get_register(s5m8767, id, &enable_reg,
 					     &enable_val);
+			if (ret) {
+				dev_err(s5m8767->dev, "error reading registers\n");
+				return ret;
+			}
 			regulators[id].enable_reg = enable_reg;
 			regulators[id].enable_mask = S5M8767_ENCTRL_MASK;
 			regulators[id].enable_val = enable_val;


Patches currently in stable-queue which might be from arnd@arndb.de are

queue-4.4/misc-bmp085-enable-building-as-a-module.patch
queue-4.4/xen-kconfig-don-t-select-input_xen_kbddev_frontend.patch
queue-4.4/regulator-s5m8767-fix-get_register-error-handling.patch
queue-4.4/asm-generic-futex-re-enable-preemption-in-futex_atomic_cmpxchg_inatomic.patch
queue-4.4/regulator-core-fix-nested-locking-of-supplies.patch
queue-4.4/paride-make-verbose-parameter-an-int-again.patch
queue-4.4/regulator-core-fix-regulator_lock_supply-regression.patch
queue-4.4/asoc-s3c24xx-use-const-snd_soc_component_driver-pointer.patch
queue-4.4/scsi_dh-force-modular-build-if-scsi-is-a-module.patch
queue-4.4/revert-regulator-core-fix-nested-locking-of-supplies.patch