[PATCH 6.19 663/844] mfd: macsmc: Initialize mutex

[Sasha Levin]

From: Janne Grunau <j@xxxxxxxxxx>

[ Upstream commit 414f65d6736342c77d4ec5e7373039f4a09250dd ]

Initialize struct apple_smc's mutex in apple_smc_probe(). Using the
mutex uninitialized surprisingly resulted only in occasional NULL
pointer dereferences in apple_smc_read() calls from the probe()
functions of sub devices.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: e038d985c9823 ("mfd: Add Apple Silicon System Management Controller")
Signed-off-by: Janne Grunau <j@xxxxxxxxxx>
Reviewed-by: Sven Peter <sven@xxxxxxxxxx>
Reviewed-by: Neal Gompa <neal@xxxxxxxxx>
Link: https://patch.msgid.link/20251231-macsmc-mutex_init-v2-1-5818c9dc9b29@xxxxxxxxxx
Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/mfd/macsmc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mfd/macsmc.c b/drivers/mfd/macsmc.c
index e3893e255ce5e..3015e8d36d6e5 100644
--- a/drivers/mfd/macsmc.c
+++ b/drivers/mfd/macsmc.c
@@ -413,6 +413,7 @@ static int apple_smc_probe(struct platform_device *pdev)
 	if (!smc)
 		return -ENOMEM;
 
+	mutex_init(&smc->mutex);
 	smc->dev = &pdev->dev;
 	smc->sram_base = devm_platform_get_and_ioremap_resource(pdev, 1, &smc->sram);
 	if (IS_ERR(smc->sram_base))
-- 
2.51.0