vt: Deadlock workaround (d5cae364) · Commits · 戴 / test

2.6.26 corrected the mutex locking on tty resizing to fix the case where you could get the tty/vt sizing out of sync. That turns out to have a deadlock. The actual fix is really major and I've got it lined up as part of the ops changes for 2.6.28 so for 2.6.26/2.6.27 it is safer to reintroduce this ages old minor bug. Signed-off-by:

Alan Cox <alan@redhat.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/vt.c

+0 −2

Original line number	Diff line number	Diff line
		@@ -916,7 +916,6 @@ int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int lines)
		ws.ws_col = vc->vc_cols;
		ws.ws_ypixel = vc->vc_scan_lines;

		mutex_lock(&vc->vc_tty->termios_mutex);
		spin_lock_irq(&vc->vc_tty->ctrl_lock);
		if ((ws.ws_row != cws->ws_row \|\| ws.ws_col != cws->ws_col))
		pgrp = get_pid(vc->vc_tty->pgrp);
		@@ -926,7 +925,6 @@ int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int lines)
		put_pid(pgrp);
		}
		*cws = ws;
		mutex_unlock(&vc->vc_tty->termios_mutex);
		}

		if (CON_IS_VISIBLE(vc))

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