This is a note to let you know that I've just added the patch titled ata: sata_mv, avoid trigerrable BUG_ON to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ata-sata_mv-avoid-trigerrable-bug_on.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From e9f691d899188679746eeb96e6cb520459eda9b4 Mon Sep 17 00:00:00 2001 From: Jiri Slaby <jslaby@xxxxxxx> Date: Thu, 31 Oct 2019 10:59:46 +0100 Subject: ata: sata_mv, avoid trigerrable BUG_ON From: Jiri Slaby <jslaby@xxxxxxx> commit e9f691d899188679746eeb96e6cb520459eda9b4 upstream. There are several reports that the BUG_ON on unsupported command in mv_qc_prep can be triggered under some circumstances: https://bugzilla.suse.com/show_bug.cgi?id=1110252 https://serverfault.com/questions/888897/raid-problems-after-power-outage https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1652185 https://bugs.centos.org/view.php?id=14998 Let sata_mv handle the failure gracefully: warn about that incl. the failed command number and return an AC_ERR_INVALID error. We can do that now thanks to the previous patch. Remove also the long-standing FIXME. [v2] use %.2x as commands are defined as hexa. Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: linux-ide@xxxxxxxxxxxxxxx Cc: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/ata/sata_mv.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/drivers/ata/sata_mv.c +++ b/drivers/ata/sata_mv.c @@ -2111,12 +2111,10 @@ static enum ata_completion_errors mv_qc_ * non-NCQ mode are: [RW] STREAM DMA and W DMA FUA EXT, none * of which are defined/used by Linux. If we get here, this * driver needs work. - * - * FIXME: modify libata to give qc_prep a return value and - * return error here. */ - BUG_ON(tf->command); - break; + ata_port_err(ap, "%s: unsupported command: %.2x\n", __func__, + tf->command); + return AC_ERR_INVALID; } mv_crqb_pack_cmd(cw++, tf->nsect, ATA_REG_NSECT, 0); mv_crqb_pack_cmd(cw++, tf->hob_lbal, ATA_REG_LBAL, 0); Patches currently in stable-queue which might be from jslaby@xxxxxxx are queue-4.19/ata-sata_mv-avoid-trigerrable-bug_on.patch queue-4.19/ata-define-ac_err_ok.patch queue-4.19/ata-make-qc_prep-return-ata_completion_errors.patch