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SubjectRe: WARNING in iov_iter_revert (2)
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>    --- a/drivers/tty/tty_io.c
> +++ b/drivers/tty/tty_io.c
> @@ -961,6 +961,9 @@ static inline ssize_t do_tty_write(
> ret = write(tty, file, tty->write_buf, size);
> if (ret <= 0)
> break;
> + /* ttyprintk historical oddity */
> + if (ret > size)
> + break;
>
> /* FIXME! Have Al check this! */
> if (ret != size)
>
> in there. Because right now we clearly do strange and not-so-wonderful
> things if the write routine returns a bigger value than it was
> passed.. Not limited to that iov_iter_revert() thing, but the whole
> loop.
>
> Comments?

Just want to comment that this fix is correct (tested),
rather than what I did [1] to return abruptly
in the beginning of do_tty_write() for write(fd, NULL, 0) case.

Let me know if I can prepare a patch with Linus's fix above.

[1] https://lore.kernel.org/lkml/20210217155536.2986178-1-snovitoll@gmail.com
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -905,6 +905,9 @@ static inline ssize_t do_tty_write(
ssize_t ret, written = 0;
unsigned int chunk;

+ if (!count)
+ return -EFAULT;
+
ret = tty_write_lock(tty, file->f_flags & O_NDELAY);
if (ret < 0)
return ret;
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