um: winch_interrupt() can happen inside of free_winch()

... so set winch->fd to -1 before doing free_irq(), to avoid having winch_interrupt() come from/during the latter and attempt to do reactivate_fd() on something that's already gone. Signed-off-by: Al Viro <[email protected]> Signed-off-by: Richard Weinberger <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
kyagi · Sep 15, 2011 · 45cd5e2 · 45cd5e2
1 parent f71f948
commit 45cd5e2
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
@@ -725,15 +725,17 @@ struct winch {
 
 static void free_winch(struct winch *winch, int free_irq_ok)
 {
+	int fd = winch->fd;
+	winch->fd = -1;
 	if (free_irq_ok)
 		free_irq(WINCH_IRQ, winch);
 
 	list_del(&winch->list);
 
 	if (winch->pid != -1)
 		os_kill_process(winch->pid, 1);
-	if (winch->fd != -1)
-		os_close_file(winch->fd);
+	if (fd != -1)
+		os_close_file(fd);
 	if (winch->stack != 0)
 		free_stack(winch->stack, 0);
 	kfree(winch);