From 24ec839c431eb79bb8f6abc00c4e1eb3b8c4d517 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 8 Dec 2006 02:36:04 -0800 Subject: [PATCH] tty: ->signal->tty locking Fix the locking of signal->tty. Use ->sighand->siglock to protect ->signal->tty; this lock is already used by most other members of ->signal/->sighand. And unless we are 'current' or the tasklist_lock is held we need ->siglock to access ->signal anyway. (NOTE: sys_unshare() is broken wrt ->sighand locking rules) Note that tty_mutex is held over tty destruction, so while holding tty_mutex any tty pointer remains valid. Otherwise the lifetime of ttys are governed by their open file handles. This leaves some holes for tty access from signal->tty (or any other non file related tty access). It solves the tty SLAB scribbles we were seeing. (NOTE: the change from group_send_sig_info to __group_send_sig_info needs to be examined by someone familiar with the security framework, I think it is safe given the SEND_SIG_PRIV from other __group_send_sig_info invocations) [schwidefsky@de.ibm.com: 3270 fix] [akpm@osdl.org: various post-viro fixes] Signed-off-by: Peter Zijlstra Acked-by: Alan Cox Cc: Oleg Nesterov Cc: Prarit Bhargava Cc: Chris Wright Cc: Roland McGrath Cc: Stephen Smalley Cc: James Morris Cc: "David S. Miller" Cc: Jeff Dike Cc: Martin Schwidefsky Cc: Jan Kara Signed-off-by: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/sparc64/solaris/misc.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'arch/sparc64/solaris') diff --git a/arch/sparc64/solaris/misc.c b/arch/sparc64/solaris/misc.c index 9ed997982f8..e84241d5f7f 100644 --- a/arch/sparc64/solaris/misc.c +++ b/arch/sparc64/solaris/misc.c @@ -423,9 +423,7 @@ asmlinkage int solaris_procids(int cmd, s32 pid, s32 pgid) Solaris setpgrp and setsid? */ ret = sys_setpgid(0, 0); if (ret) return ret; - mutex_lock(&tty_mutex); - current->signal->tty = NULL; - mutex_unlock(&tty_mutex); + proc_clear_tty(current); return process_group(current); } case 2: /* getsid */ -- cgit v1.2.3