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authorLinus Torvalds <torvalds@linux-foundation.org>2009-08-10 13:21:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-10 13:31:18 -0700
commit85dfd81dc57e8183a277ddd7a56aa65c96f3f487 (patch)
tree7b09e7d8fdc4dbe7e57a3fc2df659a5506dfaa77
parentd00aa6695b67a31be2ce5f7464da32c20cb50699 (diff)
pty: fix data loss when stopped (^S/^Q)
Commit d945cb9cc ("pty: Rework the pty layer to use the normal buffering logic") dropped the test for 'tty->stopped' in pty_write_room(), which then causes the n_tty line discipline thing to not throttle the data properly when the tty is stopped. So instead of pausing the write due to the tty being stopped, the ldisc layer would go ahead and push it down to the pty. The pty write() routine would then refuse to take the data (because it _did_ check 'stopped'), and the data wouldn't actually be written. This whole stopped test should eventually be moved into the tty ldisc layer rather than have low-level tty drivers care about these things, but right now the fix is to just re-instate the missing pty 'stopped' handling. Reported-and-tested-by: Artur Skawina <art.08.09@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/char/pty.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/char/pty.c b/drivers/char/pty.c
index 6e6942c45f5..d083c73d784 100644
--- a/drivers/char/pty.c
+++ b/drivers/char/pty.c
@@ -144,6 +144,8 @@ static int pty_write(struct tty_struct *tty, const unsigned char *buf,
static int pty_write_room(struct tty_struct *tty)
{
+ if (tty->stopped)
+ return 0;
return pty_space(tty->link);
}