The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 7373a51e7998b508af7136530f3a997b286ce81c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024061340-jogger-smooth-6cf5@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

7373a51e7998 ("nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors") 09a46acb3697 ("nilfs2: return the mapped address from nilfs_get_page()") 79ea65563ad8 ("nilfs2: Remove check for PageError")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7373a51e7998b508af7136530f3a997b286ce81c Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi konishi.ryusuke@gmail.com Date: Tue, 4 Jun 2024 22:42:55 +0900 Subject: [PATCH] nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors

The error handling in nilfs_empty_dir() when a directory folio/page read fails is incorrect, as in the old ext2 implementation, and if the folio/page cannot be read or nilfs_check_folio() fails, it will falsely determine the directory as empty and corrupt the file system.

In addition, since nilfs_empty_dir() does not immediately return on a failed folio/page read, but continues to loop, this can cause a long loop with I/O if i_size of the directory's inode is also corrupted, causing the log writer thread to wait and hang, as reported by syzbot.

Fix these issues by making nilfs_empty_dir() immediately return a false value (0) if it fails to get a directory folio/page.

Link: https://lkml.kernel.org/r/20240604134255.7165-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Reported-by: syzbot+c8166c541d3971bf6c87@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c8166c541d3971bf6c87 Fixes: 2ba466d74ed7 ("nilfs2: directory entry operations") Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org

diff --git a/fs/nilfs2/dir.c b/fs/nilfs2/dir.c index a002a44ff161..52e50b1b7f22 100644 --- a/fs/nilfs2/dir.c +++ b/fs/nilfs2/dir.c @@ -607,7 +607,7 @@ int nilfs_empty_dir(struct inode *inode)

kaddr = nilfs_get_folio(inode, i, &folio); if (IS_ERR(kaddr)) - continue; + return 0;

de = (struct nilfs_dir_entry *)kaddr; kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);