[PATCH 6.18 593/752] mfd: macsmc: Initialize mutex

Sasha Levin
2026-02-28T17:56:44Z

From: Janne Grunau <j@jannau.net>

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

diff --git a/drivers/mfd/macsmc.c b/drivers/mfd/macsmc.c
index e6cdae221f1d4..3228e79c86eb5 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