4.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jiri Slaby <[email protected]> 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 <[email protected]> Fixes: 348487cb28e6 Cc: Ulf Hansson <[email protected]> Cc: Haibo Chen <[email protected]> Signed-off-by: Ulf Hansson <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/mmc/host/sdhci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -846,7 +846,7 @@ static void sdhci_prepare_data(struct sd 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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
