This is a note to let you know that I've just added the patch titled

mtd: nand: gpmi: Fix failure when a erased page has a bitflip at BBM

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: mtd-nand-gpmi-fix-failure-when-a-erased-page-has-a-bitflip-at-bbm.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Wed Feb 28 16:23:28 CET 2018

From: Sascha Hauer s.hauer@pengutronix.de Date: Tue, 5 Dec 2017 11:51:40 +0100 Subject: mtd: nand: gpmi: Fix failure when a erased page has a bitflip at BBM

From: Sascha Hauer s.hauer@pengutronix.de

[ Upstream commit fdf2e821052958a114618a95ab18a300d0b080cb ]

When erased subpages are read then the BCH decoder returns STATUS_ERASED if they are all empty, or STATUS_UNCORRECTABLE if there are bitflips. When there are bitflips, we have to set these bits again to show the upper layers a completely erased page. When a bitflip happens in the exact byte where the bad block marker is, then this byte is swapped with another byte in block_mark_swapping(). The correction code then detects a bitflip in another subpage and no longer corrects the bitflip where it really happens.

Correct this behaviour by calling block_mark_swapping() after the bitflips have been corrected.

In our case UBIFS failed with this bug because it expects erased pages to be really empty:

UBIFS error (pid 187): ubifs_scan: corrupt empty space at LEB 36:118735 UBIFS error (pid 187): ubifs_scanned_corruption: corruption at LEB 36:118735 UBIFS error (pid 187): ubifs_scanned_corruption: first 8192 bytes from LEB 36:118735 UBIFS error (pid 187): ubifs_scan: LEB 36 scanning failed UBIFS error (pid 187): do_commit: commit failed, error -117

Signed-off-by: Sascha Hauer s.hauer@pengutronix.de Reviewed-by: Richard Weinberger richard@nod.at Acked-by: Boris Brezillon boris.brezillon@free-electrons.com Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c @@ -1067,9 +1067,6 @@ static int gpmi_ecc_read_page(struct mtd return ret; }

- /* handle the block mark swapping */ - block_mark_swapping(this, payload_virt, auxiliary_virt); - /* Loop over status bytes, accumulating ECC status. */ status = auxiliary_virt + nfc_geo->auxiliary_status_offset;

@@ -1158,6 +1155,9 @@ static int gpmi_ecc_read_page(struct mtd max_bitflips = max_t(unsigned int, max_bitflips, *status); }

+ /* handle the block mark swapping */ + block_mark_swapping(this, buf, auxiliary_virt); + if (oob_required) { /* * It's time to deliver the OOB bytes. See gpmi_ecc_read_oob()

Patches currently in stable-queue which might be from s.hauer@pengutronix.de are

queue-4.14/mtd-nand-gpmi-fix-failure-when-a-erased-page-has-a-bitflip-at-bbm.patch