From: Abhishek Sahu Date: Wed, 20 Jun 2018 07:27:35 +0000 (+0530) Subject: mtd: rawnand: qcom: fix null pointer access for erased page detection X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2f610386736d9e5dc69fa06374138f9712690921;p=linux.git mtd: rawnand: qcom: fix null pointer access for erased page detection parse_read_errors can be called with only oob_buf in which case data_buf will be NULL. If data_buf is NULL, then don’t treat this page as completely erased in case of ECC uncorrectable error for RS ECC. For BCH ECC, the controller itself tells regarding erased page in status register. Signed-off-by: Abhishek Sahu Signed-off-by: Miquel Raynal --- diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c index 0d931d51f85ae..a831f9cb458a4 100644 --- a/drivers/mtd/nand/raw/qcom_nandc.c +++ b/drivers/mtd/nand/raw/qcom_nandc.c @@ -1611,13 +1611,24 @@ static int parse_read_errors(struct qcom_nand_host *host, u8 *data_buf, int ret, ecclen, extraooblen; void *eccbuf; - /* ignore erased codeword errors */ + /* + * For BCH ECC, ignore erased codeword errors, if + * ERASED_CW bits are set. + */ if (host->bch_enabled) { erased = (erased_cw & ERASED_CW) == ERASED_CW ? true : false; - } else { + /* + * For RS ECC, HW reports the erased CW by placing + * special characters at certain offsets in the buffer. + * These special characters will be valid only if + * complete page is read i.e. data_buf is not NULL. + */ + } else if (data_buf) { erased = erased_chunk_check_and_fixup(data_buf, data_len); + } else { + erased = false; } if (erased) { @@ -1665,7 +1676,8 @@ static int parse_read_errors(struct qcom_nand_host *host, u8 *data_buf, max_bitflips = max(max_bitflips, stat); } - data_buf += data_len; + if (data_buf) + data_buf += data_len; if (oob_buf) oob_buf += oob_len + ecc->bytes; }