From: Peter Collingbourne <pcc@google.com> commit b503087445ce7e45fabdee87ca9e460d5b5b5168 upstream. If extended CSD was not available, the eMMC driver would incorrectly set the block size to 0, as the data_sector_size field of ext_csd was never initialized. This issue was exposed by commit 817046ecddbc ("block: Align max_hw_sectors to logical blocksize") which caused max_sectors and max_hw_sectors to be set to 0 after setting the block size to 0, resulting in a kernel panic in bio_split when attempting to read from the device. Fix it by only reading the block size from ext_csd if it is available. Fixes: a5075eb94837 ("mmc: block: Allow disabling 512B sector size emulation") Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Link: https://linux-review.googlesource.com/id/If244d178da4d86b52034459438fec295b0... Acked-by: Adrian Hunter <adrian.hunter@intel.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210114201405.2934886-1-pcc@google.com Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/mmc/core/queue.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c index 9b31cd6b6062b..9aaf5a2d83c3b 100644 --- a/drivers/mmc/core/queue.c +++ b/drivers/mmc/core/queue.c @@ -364,8 +364,10 @@ static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card) min(host->max_blk_count, host->max_req_size / 512)); blk_queue_max_segments(mq->queue, host->max_segs); - if (mmc_card_mmc(card)) + if (mmc_card_mmc(card) && card->ext_csd.data_sector_size) { block_size = card->ext_csd.data_sector_size; + WARN_ON(block_size != 512 && block_size != 4096); + } blk_queue_logical_block_size(mq->queue, block_size); blk_queue_max_segment_size(mq->queue, -- 2.25.1