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Commit 81c6ce9b authored by Nick Piggin's avatar Nick Piggin Committed by Linus Torvalds
Browse files

vt: fix vc_resize locking 



Lockdep says we can't take tasklist lock or sighand lock inside ctrl_lock.

Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Acked-by: default avatarAlan Cox <alan@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent dfcceb26

drivers/char/vt.c

+8 −5
Original line number Diff line number Diff line
@@ -909,7 +909,7 @@ int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int lines) 


	if (vc->vc_tty) {

		struct winsize ws, *cws = &vc->vc_tty->winsize;

		unsigned long flags;

		struct pid *pgrp = NULL;



		memset(&ws, 0, sizeof(ws));

		ws.ws_row = vc->vc_rows;
@@ -917,11 +917,14 @@ int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int lines) 
		ws.ws_ypixel = vc->vc_scan_lines;



		mutex_lock(&vc->vc_tty->termios_mutex);

		spin_lock_irqsave(&vc->vc_tty->ctrl_lock, flags);

		if ((ws.ws_row != cws->ws_row || ws.ws_col != cws->ws_col) &&

		    vc->vc_tty->pgrp)

		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);

		spin_unlock_irq(&vc->vc_tty->ctrl_lock);

		if (pgrp) {

			kill_pgrp(vc->vc_tty->pgrp, SIGWINCH, 1);

		spin_unlock_irqrestore(&vc->vc_tty->ctrl_lock, flags);

			put_pid(pgrp);

		}

		*cws = ws;

		mutex_unlock(&vc->vc_tty->termios_mutex);

	}