On Mon, Feb 27, 2023 at 5:46 PM <linux@xxxxxxxxxxxxxx> wrote: > > This still seems to be broken for me. Looks that way. > I still need the patch from > > https://lore.kernel.org/lkml/20230220064612.1783-1-linux@xxxxxxxxxxxxxx/ .. and that has the same problem with "what if the error happens during an iteration that wasn't the first, and we already succeeded partially". The "goto unlock_out" is bogus, since it jumps over all the "update pos and check if we read something". It was the correct thing to do *above* the loop, but not inside the loop. IOW, I think the proper patch is to also turn the "goto unlock_out" into a "break". Mind testing something like this (whitespace-damaged, but you get the idea): --- a/drivers/tty/vt/vc_screen.c +++ b/drivers/tty/vt/vc_screen.c @@ -403,10 +403,11 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) unsigned int this_round, skip = 0; int size; - ret = -ENXIO; vc = vcs_vc(inode, &viewed); - if (!vc) - goto unlock_out; + if (!vc) { + ret = -ENXIO; + break; + } /* Check whether we are above size each round, * as copy_to_user at the end of this loop which hopefully really fixes this (at least I don't see any other "goto unlock_out" cases). Linus
