From: Tachino Nobuhiro <tachino@open.nm.fujitsu.co.jp>
To: linux-kernel@vger.kernel.org
Subject: [BUG-2.4.10] deadlock in do_truncate() and shmem_getpage()
Date: Tue, 02 Oct 2001 15:14:21 +0900 [thread overview]
Message-ID: <vghy1sci.wl@nisaaru.dvs.cs.fujitsu.co.jp> (raw)
Hello,
I found a a deadlock bug in v2.4.10 due to invert locking order between
inode->i_truncate_sem and inode->i_sem.
Sequence is following.
do_truncate()
down(&inode->i_sem);
down_write(&inode->i_truncate_sem);
do_no_page()
down_read(&inode->i_truncate_sem);
shmem_nopage();
shmem_getpage();
down(&inode->i_sem);
Following patch works for me.
diff -r -u -N linux.org/fs/open.c linux/fs/open.c
--- linux.org/fs/open.c Tue Oct 2 11:35:47 2001
+++ linux/fs/open.c Tue Oct 2 11:45:33 2001
@@ -81,13 +81,13 @@
if (length < 0)
return -EINVAL;
- down(&inode->i_sem);
down_write(&inode->i_truncate_sem);
+ down(&inode->i_sem);
newattrs.ia_size = length;
newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME;
error = notify_change(dentry, &newattrs);
- up_write(&inode->i_truncate_sem);
up(&inode->i_sem);
+ up_write(&inode->i_truncate_sem);
return error;
}
next reply other threads:[~2001-10-02 6:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-10-02 6:14 Tachino Nobuhiro [this message]
2001-10-02 6:33 ` [BUG-2.4.10] deadlock in do_truncate() and shmem_getpage() Andrew Morton
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