| Message ID | 20210611090330.13039-1-tiwai@suse.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | mmc: sdhci: Clear unused bounce buffer at DMA mmap error path | expand |
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 <tiwai@suse.de> One minor comment below, otherwise: Acked-by: Adrian Hunter <adrian.hunter@intel.com> > --- > 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 */ >
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); + 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 */
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 <tiwai@suse.de> --- drivers/mmc/host/sdhci.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)