Patch from Rik van Riel the following patch, against today's BK tree, fixes a small SMP race in disassociate_ctty. This function gets called from do_exit, without the BKL held. However, it sets the *tty variable before grabbing the bkl, then makes decisions on what the variable was set to before the lock was grabbed, despite the fact that another process could modify its ->tty pointer in this same function. char/tty_io.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletion(-) diff -puN drivers/char/tty_io.c~disassociate_tty-fix drivers/char/tty_io.c --- 25/drivers/char/tty_io.c~disassociate_tty-fix 2003-02-09 02:47:09.000000000 -0800 +++ 25-akpm/drivers/char/tty_io.c 2003-02-09 02:47:09.000000000 -0800 @@ -581,7 +581,7 @@ EXPORT_SYMBOL(tty_hung_up_p); */ void disassociate_ctty(int on_exit) { - struct tty_struct *tty = current->tty; + struct tty_struct *tty; struct task_struct *p; struct list_head *l; struct pid *pid; @@ -589,6 +589,7 @@ void disassociate_ctty(int on_exit) lock_kernel(); + tty = current->tty; if (tty) { tty_pgrp = tty->pgrp; if (on_exit && tty->driver.type != TTY_DRIVER_TYPE_PTY) _