From: Miklos Szeredi <mszeredi(a)redhat.com>
mainline inclusion
from mainline-5.14
commit 76224355db7570cbe6b6f75c8929a1558828dd55
category: bugfix
bugzilla: 181107
CVE: NA
---------------------------
fuse_finish_open() will be called with FUSE_NOWRITE in case of atomic
O_TRUNC. This can deadlock with fuse_wait_on_page_writeback() in
fuse_launder_page() triggered by invalidate_inode_pages2().
Fix by replacing invalidate_inode_pages2() in fuse_finish_open() with a
truncate_pagecache() call. This makes sense regardless of FOPEN_KEEP_CACHE
or fc->writeback cache, so do it unconditionally.
Reported-by: Xie Yongji <xieyongji(a)bytedance.com>
Reported-and-tested-by: syzbot+bea44a5189836d956894(a)syzkaller.appspotmail.com
Fixes: e4648309b85a ("fuse: truncate pending writes on O_TRUNC")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi(a)redhat.com>
Conflict: fs/fuse/file.c
Signed-off-by: Yu Kuai <yukuai3(a)huawei.com>
Reviewed-by: Zhang Yi <yi.zhang(a)huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang(a)huawei.com>
---
fs/fuse/file.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 41e2a7b567d7f..5ecabacabd477 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -178,8 +178,6 @@ void fuse_finish_open(struct inode *inode, struct file *file)
if (ff->open_flags & FOPEN_DIRECT_IO)
file->f_op = &fuse_direct_io_file_operations;
- if (!(ff->open_flags & FOPEN_KEEP_CACHE))
- invalidate_inode_pages2(inode->i_mapping);
if (ff->open_flags & FOPEN_STREAM)
stream_open(inode, file);
else if (ff->open_flags & FOPEN_NONSEEKABLE)
@@ -191,10 +189,13 @@ void fuse_finish_open(struct inode *inode, struct file *file)
fi->attr_version = ++fc->attr_version;
i_size_write(inode, 0);
spin_unlock(&fc->lock);
+ truncate_pagecache(inode, 0);
fuse_invalidate_attr(inode);
if (fc->writeback_cache)
file_update_time(file);
- }
+ } else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
+ invalidate_inode_pages2(inode->i_mapping);
+
if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
fuse_link_write_file(file);
}
--
2.25.1