um: line: Don't free winch (with IRQ) under spinlock (f4ab7818) · Commits · 戴 / test

Lockdep correctly complains that one shouldn't call um_free_irq() with free_irq() inside under a spinlock since that will attempt to acquire a mutex. Rearrange the code to keep the list manipulations under the lock while moving the actual freeing outside of it, to avoid this. In particular, this removes the lockdep complaint at shutdown that I was seeing with lockdep enabled. Signed-off-by:

Johannes Berg <johannes.berg@intel.com> Acked-By:

<anton.ivanov@cambridgegreys.com> Signed-off-by:

Richard Weinberger <richard@nod.at>

arch/um/drivers/line.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -608,7 +608,6 @@ static void free_winch(struct winch *winch)
		winch->fd = -1;
		if (fd != -1)
		os_close_file(fd);
		list_del(&winch->list);
		__free_winch(&winch->work);
		}

		@@ -709,6 +708,8 @@ static void unregister_winch(struct tty_struct *tty)
		winch = list_entry(ele, struct winch, list);
		wtty = tty_port_tty_get(winch->port);
		if (wtty == tty) {
		list_del(&winch->list);
		spin_unlock(&winch_handler_lock);
		free_winch(winch);
		break;
		}
		@@ -719,14 +720,17 @@ static void unregister_winch(struct tty_struct *tty)

		static void winch_cleanup(void)
		{
		struct list_head ele, next;
		struct winch *winch;

		spin_lock(&winch_handler_lock);
		while ((winch = list_first_entry_or_null(&winch_handlers,
		struct winch, list))) {
		list_del(&winch->list);
		spin_unlock(&winch_handler_lock);

		list_for_each_safe(ele, next, &winch_handlers) {
		winch = list_entry(ele, struct winch, list);
		free_winch(winch);

		spin_lock(&winch_handler_lock);
		}

		spin_unlock(&winch_handler_lock);

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