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mtk-sd: Prevent memory corruption from DMA map failure

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If msdc_prepare_data() fails to map the DMA region, the request is
not prepared for data receiving, but msdc_start_data() proceeds
the DMA with previous setting.
Since this will lead a memory corruption, we have to stop the
request operation soon after the msdc_prepare_data() fails to
prepare it.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fixes: 208489032b ("mmc: mediatek: Add Mediatek MMC driver")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/174972756982.3337526.6755001617701603082.stgit@mhiramat.tok.corp.google.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Masami Hiramatsu (Google) 2025-06-12 20:26:10 +09:00 • committed by Ulf Hansson
parent 539d80575b
commit f5de469990
1 changed files with 16 additions and 1 deletions
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17
drivers/mmc/host/mtk-sd.c
View file

@ -853,6 +853,11 @@ static void msdc_prepare_data(struct msdc_host *host, struct mmc_data *data)
}
}
static bool msdc_data_prepared(struct mmc_data *data)
{
return data->host_cookie & MSDC_PREPARE_FLAG;
}
static void msdc_unprepare_data(struct msdc_host *host, struct mmc_data *data)
{
if (data->host_cookie & MSDC_ASYNC_FLAG)
@ -1484,8 +1489,18 @@ static void msdc_ops_request(struct mmc_host *mmc, struct mmc_request *mrq)
WARN_ON(!host->hsq_en && host->mrq);
host->mrq = mrq;
if (mrq->data)
if (mrq->data) {
msdc_prepare_data(host, mrq->data);
if (!msdc_data_prepared(mrq->data)) {
/*
* Failed to prepare DMA area, fail fast before
* starting any commands.
*/
mrq->cmd->error = -ENOSPC;
mmc_request_done(mmc_from_priv(host), mrq);
return;
}
}
/* if SBC is required, we have HW option and SW option.
* if HW option is enabled, and SBC does not have "special" flags,