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From:   Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
To:     vkoul@kernel.org
Cc:     yung-chuan.liao@linux.intel.com,
        pierre-louis.bossart@linux.intel.com, sanyog.r.kale@intel.com,
        guennadi.liakhovetski@linux.intel.com, rander.wang@intel.com,
        alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Subject: [PATCH] soundwire: bus: stop dereferencing invalid slave pointer
Date:   Tue, 12 Oct 2021 11:15:21 +0100
Message-Id: <20211012101521.32087-1-srinivas.kandagatla@linaro.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Slave pointer is invalid after end of list iteration, using this
would result in below Memory abort.

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
...
Call trace:
 __dev_printk+0x34/0x7c
 _dev_warn+0x6c/0x90
 sdw_bus_exit_clk_stop+0x194/0x1d0
 swrm_runtime_resume+0x13c/0x238
 pm_generic_runtime_resume+0x2c/0x48
 __rpm_callback+0x44/0x150
 rpm_callback+0x6c/0x78
 rpm_resume+0x314/0x558
 rpm_resume+0x378/0x558
 rpm_resume+0x378/0x558
 __pm_runtime_resume+0x3c/0x88

Use bus->dev instead to print this error message.

Fixes: b50bb8ba369cd ("soundwire: bus: handle -ENODATA errors in clock stop/start sequences")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
 drivers/soundwire/bus.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 1b115734a8f6..67369e941d0d 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -1110,7 +1110,7 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
 	if (!simple_clk_stop) {
 		ret = sdw_bus_wait_for_clk_prep_deprep(bus, SDW_BROADCAST_DEV_NUM);
 		if (ret < 0)
-			dev_warn(&slave->dev, "clock stop deprepare wait failed:%d\n", ret);
+			dev_warn(bus->dev, "clock stop deprepare wait failed:%d\n", ret);
 	}
 
 	list_for_each_entry(slave, &bus->slaves, node) {
-- 
2.21.0