linux-kernel - [PATCH 5/9] um: winch_interrupt() can happen inside of free

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Date:	Mon, 29 Aug 2011 18:13:35 +0200
From:	Richard Weinberger <richard@....at>
To:	akpm@...ux-foundation.org
Cc:	linux-kernel@...r.kernel.org,
	user-mode-linux-devel@...ts.sourceforge.net,
	Al Viro <viro@....linux.org.uk>,
	Al Viro <viro@...iv.linux.org.uk>,
	Richard Weinberger <richard@....at>
Subject: [PATCH 5/9] um: winch_interrupt() can happen inside of free_winch()

From: Al Viro <viro@....linux.org.uk>

... 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 <viro@...iv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@....at>
---
 arch/um/drivers/line.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index c5bff1d..91bf1894 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -725,6 +725,8 @@ 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);
 
@@ -732,8 +734,8 @@ static void free_winch(struct winch *winch, int free_irq_ok)
 
 	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);
-- 
1.7.6.1

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