Hi Shawn, I am not sure how why blkdev_roset is iocl function call is landing in mmc_blk_ioctl. Could it be a IOCTL mapping issue ? Regards Seshagiri -----Original Message----- From: Shawn Lin [mailto:shawn.lin@xxxxxxxxxxxxxx] Sent: Monday, March 07, 2016 11:54 AM To: Ulf Hansson Cc: Seshagiri Holi; Jonathan Hunter; Shawn Lin; stable@xxxxxxxxxxxxxxx; #@263.net; 4.4.x@xxxxxxx Subject: [PATCH] mmc: block: fix ABI regression of mmc_blk_ioctl We should return -EINVAL if cmd is not MMC_IOC_CMD or MMC_IOC_MULTI_CMD, otherwise blkdev_roset will return -EPERM. Android-adb calls make_block_device_writable with ioctl(BLKROSET), which will return error, make remount failed: remount of /system failed; couldn't make block device writable: Operation not permitted openat(AT_FDCWD, "/dev/block/platform/ff420000.dwmmc/by-name/system", O_RDONLY) = 3 ioctl(3, BLKROSET, 0) = -1 EPERM (Operation not permitted) Fixes: a5f5774c55a2 ("mmc: block: Add new ioctl to send multi commands") Cc: <stable@xxxxxxxxxxxxxxx> # 4.4.x Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> --- drivers/mmc/card/block.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index 47bc87d..170f099 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -688,6 +688,9 @@ cmd_err: static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { + if (cmd != MMC_IOC_CMD && cmd != MMC_IOC_MULTI_CMD) + return -EINVAL; + /* * The caller must have CAP_SYS_RAWIO, and must be calling this on the * whole block device, not on a partition. This prevents overspray -- 2.3.7 ----------------------------------------------------------------------------------- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. ----------------------------------------------------------------------------------- -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html