This is a note to let you know that I've just added the patch titled rsxx: Return -EFAULT if copy_to_user() fails to the 5.4-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: rsxx-return-efault-if-copy_to_user-fails.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 5dcc5727f289986295b88045be301fab009dac6e Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Date: Wed Mar 3 13:59:12 2021 +0300 rsxx: Return -EFAULT if copy_to_user() fails [ Upstream commit 77516d25f54912a7baedeeac1b1b828b6f285152 ] The copy_to_user() function returns the number of bytes remaining but we want to return -EFAULT to the user if it can't complete the copy. The "st" variable only holds zero on success or negative error codes on failure so the type should be int. Fixes: 36f988e978f8 ("rsxx: Adding in debugfs entries.") Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/block/rsxx/core.c b/drivers/block/rsxx/core.c index 10f6368117d8..804d28faa97b 100644 --- a/drivers/block/rsxx/core.c +++ b/drivers/block/rsxx/core.c @@ -165,15 +165,17 @@ static ssize_t rsxx_cram_read(struct file *fp, char __user *ubuf, { struct rsxx_cardinfo *card = file_inode(fp)->i_private; char *buf; - ssize_t st; + int st; buf = kzalloc(cnt, GFP_KERNEL); if (!buf) return -ENOMEM; st = rsxx_creg_read(card, CREG_ADD_CRAM + (u32)*ppos, cnt, buf, 1); - if (!st) - st = copy_to_user(ubuf, buf, cnt); + if (!st) { + if (copy_to_user(ubuf, buf, cnt)) + st = -EFAULT; + } kfree(buf); if (st) return st;