linux-kernel - Re: [syzbot] Re: [syzbot] [v9fs?] WARNING in v9fs_begin

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Message-ID: <0000000000001c85b0061f3b4484@google.com>
Date: Fri, 09 Aug 2024 00:41:06 -0700
From: syzbot <syzbot+0b74d367d6e80661d6df@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org
Subject: Re: [syzbot] Re: [syzbot] [v9fs?] WARNING in v9fs_begin_writeback

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Subject: Re: [syzbot] [v9fs?] WARNING in v9fs_begin_writeback
Author: lizhi.xu@...driver.com

add file refconut when add fid to list

#syz test: upstream c0ecd6388360

diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index e0d34e4e9076..99c7015396ab 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -219,6 +219,14 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
 			retval = filemap_fdatawrite(inode->i_mapping);
 
 		spin_lock(&inode->i_lock);
+		if (test_bit(I_SYNC, &inode->i_state)) {
+			spin_unlock(&inode->i_lock);
+			if (wait_on_bit_timeout(&inode->i_state, I_SYNC,
+						TASK_UNINTERRUPTIBLE, HZ))
+				return -EBUSY;
+			printk("del, ind: %p, ino: %lx, ino is dirty: %d, %s\n", inode, inode->i_ino, inode->i_state & I_SYNC,  __func__);
+			spin_lock(&inode->i_lock);
+		}
 		hlist_del(&fid->ilist);
 		spin_unlock(&inode->i_lock);
 		put_err = p9_fid_put(fid);