Re: [PATCH] mmc: sdhci: Clear unused bounce buffer at DMA mmap error path
From: Adrian Hunter <adrian.hunter@intel.com>
Date: 2021-06-11 09:55:55
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On 11/06/21 12:03 pm, Takashi Iwai wrote:
When DMA-mapping of the bounce buffer fails, the driver tries to fall back, but it leaves the allocated host->bounce_buffer although its size is zero. Later on, the driver checks the use of bounce buffer with host->bounce_buffer pointer, and it tries to use the buffer incorrectly, resulting in Oops. This patch clears the release the unused buffer and clears the bounce_buffer pointer for addressing the problem. Signed-off-by: Takashi Iwai <redacted>
One minor comment below, otherwise: Acked-by: Adrian Hunter <adrian.hunter@intel.com>
quoted hunk ↗ jump to hunk
--- drivers/mmc/host/sdhci.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index bf238ade1602..5f467b98ca88 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c@@ -4072,9 +4072,13 @@ static void sdhci_allocate_bounce_buffer(struct sdhci_host *host) bounce_size, DMA_BIDIRECTIONAL); ret = dma_mapping_error(mmc_dev(mmc), host->bounce_addr); - if (ret) + if (ret) { + devm_kfree(mmc->parent, host->bounce_buffer);
Everywhere else in this function mmc_dev(mmc) is used, so maybe use it here too instead of mmc->parent.
+ host->bounce_buffer = NULL; /* Again fall back to max_segs == 1 */ return; + } + host->bounce_buffer_size = bounce_size; /* Lie about this since we're bouncing */