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| author | Jiri Slaby <jslaby@suse.cz> | 2015-06-12 12:45:02 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-07-10 19:49:33 +0300 |
| commit | 4b81f9f8194ffa58b27d269233c9f778b758cb2b (patch) | |
| tree | a9d47744b3474679b1742c06614d74707e14395a | |
| parent | 396887ba3a77ee7f8b17ea85afa8501262e230b4 (diff) | |
| download | linux-4b81f9f8194ffa58b27d269233c9f778b758cb2b.tar.xz | |
mmc: sdhci: fix low memory corruption
commit 62a7f368ffbc13d9aedfdd7aeae711b177db69ac upstream.
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>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 c80287a02735..9231cdfe2757 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -848,7 +848,7 @@ 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. |