[PATCH v2 2/6] firmware: samsung: acpm: Fix mailbox channel leak on probe error
From: Tudor Ambarus <tudor.ambarus@linaro.org>
Date: 2026-04-27 15:04:14
Also in:
linux-arm-kernel, linux-samsung-soc, lkml
Subsystem:
arm/samsung s3c, s5p and exynos arm architectures, samsung exynos acpm mailbox protocol, the rest · Maintainers:
Krzysztof Kozlowski, Peter Griffin, Tudor Ambarus, Linus Torvalds
Sashiko identified the leak at [1].
The ACPM driver allocates hardware mailbox channels using
`mbox_request_channel()` during `acpm_channels_init()`. However, the
driver lacked a `.remove` callback and did not free these channels on
subsequent error paths inside `acpm_probe()`.
Additionally, if `acpm_achan_alloc_cmds()` failed during the channel
initialization loop, the function returned immediately, bypassing the
manual cleanup and permanently leaking any channels successfully
requested in previous loop iterations.
Fix this by modifying `acpm_free_mbox_chans()` to match the `devres`
action signature and registering it via `devm_add_action_or_reset()`.
Cc: stable@vger.kernel.org
Fixes: a88927b534ba ("firmware: add Exynos ACPM protocol driver")
Closes: https://sashiko.dev/#/patchset/20260420-acpm-tmu-v3-0-3dc8e93f0b26%40linaro.org [1]
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
---
drivers/firmware/samsung/exynos-acpm.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/firmware/samsung/exynos-acpm.c b/drivers/firmware/samsung/exynos-acpm.c
index e95edc350efa..bd0d48e9d157 100644
--- a/drivers/firmware/samsung/exynos-acpm.c
+++ b/drivers/firmware/samsung/exynos-acpm.c@@ -529,8 +529,9 @@ static int acpm_achan_alloc_cmds(struct acpm_chan *achan) * acpm_free_mbox_chans() - free mailbox channels. * @acpm: pointer to driver data. */ -static void acpm_free_mbox_chans(struct acpm_info *acpm) +static void acpm_free_mbox_chans(void *data) { + struct acpm_info *acpm = data; int i; for (i = 0; i < acpm->num_chans; i++)
@@ -558,6 +559,10 @@ static int acpm_channels_init(struct acpm_info *acpm) if (!acpm->chans) return -ENOMEM; + ret = devm_add_action_or_reset(dev, acpm_free_mbox_chans, acpm); + if (ret) + return dev_err_probe(dev, ret, "Failed to add mbox free action.\n"); + chans_shmem = acpm->sram_base + readl(&shmem->chans); for (i = 0; i < acpm->num_chans; i++) {
@@ -579,10 +584,8 @@ static int acpm_channels_init(struct acpm_info *acpm) cl->dev = dev; achan->chan = mbox_request_channel(cl, 0); - if (IS_ERR(achan->chan)) { - acpm_free_mbox_chans(acpm); + if (IS_ERR(achan->chan)) return PTR_ERR(achan->chan); - } } return 0;
--
2.54.0.rc2.544.gc7ae2d5bb8-goog