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| author | Jiri Slaby <jslaby@suse.cz> | 2015-06-12 11:45:02 +0200 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2015-06-16 08:58:36 +0200 |
| commit | 62a7f368ffbc13d9aedfdd7aeae711b177db69ac (patch) | |
| tree | 1bf86a7dd5c75cac92d58f26b9f83da8aad70251 /drivers/mmc | |
| parent | b5e97d6e58617b9d6a3838ede6ccd3883035dbf3 (diff) | |
| download | op-kernel-dev-62a7f368ffbc13d9aedfdd7aeae711b177db69ac.zip op-kernel-dev-62a7f368ffbc13d9aedfdd7aeae711b177db69ac.tar.gz | |
mmc: sdhci: fix low memory corruption
When dma mapping (dma_map_sg) fails in sdhci_pre_dma_transfer, -EINVAL
is returned. There are 3 callers of sdhci_pre_dma_transfer:
* sdhci_pre_req and sdhci_adma_table_pre: handle negative return
* sdhci_prepare_data: handles 0 (error) and "else" (good) only
sdhci_prepare_data is therefore broken. When it receives -EINVAL from
sdhci_pre_dma_transfer, it assumes 1 sg mapping was mapped. Later,
this non-existent mapping with address 0 is kmap'ped and written to:
Corrupted low memory at ffff880000001000 (1000 phys) = 22b7d67df2f6d1cf
Corrupted low memory at ffff880000001008 (1008 phys) = 63848a5216b7dd95
Corrupted low memory at ffff880000001010 (1010 phys) = 330eb7ddef39e427
Corrupted low memory at ffff880000001018 (1018 phys) = 8017ac7295039bda
Corrupted low memory at ffff880000001020 (1020 phys) = 8ce039eac119074f
...
So teach sdhci_prepare_data to understand negative return values from
sdhci_pre_dma_transfer and disable DMA in that case, as well as for
zero.
It was introduced in 348487cb28e66b032bae1b38424d81bf5b444408 (mmc:
sdhci: use pipeline mmc requests to improve performance). The commit
seems to be suspicious also by assigning host->sg_count both in
sdhci_pre_dma_transfer and sdhci_adma_table_pre.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable@vger.kernel.org # 4.0+
Fixes: 348487cb28e6
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Haibo Chen <haibo.chen@freescale.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/host/sdhci.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 706bb60..bc14452 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -834,7 +834,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd) int sg_cnt; sg_cnt = sdhci_pre_dma_transfer(host, data, NULL); - if (sg_cnt == 0) { + if (sg_cnt <= 0) { /* * This only happens when someone fed * us an invalid request. |
