This is a note to let you know that I've just added the patch titled libata: array underflow in ata_find_dev() to the 4.9-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: libata-array-underflow-in-ata_find_dev.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 59a5e266c3f5c1567508888dd61a45b86daed0fa Mon Sep 17 00:00:00 2001 From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Wed, 19 Jul 2017 13:06:41 +0300 Subject: libata: array underflow in ata_find_dev() From: Dan Carpenter <dan.carpenter@xxxxxxxxxx> commit 59a5e266c3f5c1567508888dd61a45b86daed0fa upstream. My static checker complains that "devno" can be negative, meaning that we read before the start of the loop. I've looked at the code, and I think the warning is right. This come from /proc so it's root only or it would be quite a quite a serious bug. The call tree looks like this: proc_scsi_write() <- gets id and channel from simple_strtoul() -> scsi_add_single_device() <- calls shost->transportt->user_scan() -> ata_scsi_user_scan() -> ata_find_dev() Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/ata/libata-scsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -2971,10 +2971,12 @@ static unsigned int atapi_xlat(struct at static struct ata_device *ata_find_dev(struct ata_port *ap, int devno) { if (!sata_pmp_attached(ap)) { - if (likely(devno < ata_link_max_devices(&ap->link))) + if (likely(devno >= 0 && + devno < ata_link_max_devices(&ap->link))) return &ap->link.device[devno]; } else { - if (likely(devno < ap->nr_pmp_links)) + if (likely(devno >= 0 && + devno < ap->nr_pmp_links)) return &ap->pmp_link[devno].device[0]; } Patches currently in stable-queue which might be from dan.carpenter@xxxxxxxxxx are queue-4.9/libata-array-underflow-in-ata_find_dev.patch