linux-kernel - Re: [syzbot] [PATCH] handle EFSCORRUPTED, drop EXT4_STATE_MAY_INLINE

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Date: Mon, 01 Jul 2024 01:29:47 -0700
From: syzbot <syzbot+18df508cf00a0598d9a6@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [PATCH] handle EFSCORRUPTED, drop EXT4_STATE_MAY_INLINE_DATA
 sanity check

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***

Subject: [PATCH] handle EFSCORRUPTED, drop EXT4_STATE_MAY_INLINE_DATA sanity check
Author: wojciech.gladysz@...ogain.com

#syz test: https://linux.googlesource.com/linux/kernel/git/torvalds/linux
---
 fs/buffer.c     | 5 ++++-
 fs/ext4/inode.c | 5 +++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 4f73d23c2c46..10514fa9851c 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2163,7 +2163,10 @@ static void __block_commit_write(struct folio *folio, size_t from, size_t to)
 	unsigned blocksize;
 	struct buffer_head *bh, *head;
 
-	bh = head = folio_buffers(folio);
+	head = folio_buffers(folio);
+	if (!head)
+		return;
+	bh = head;
 	blocksize = bh->b_size;
 
 	block_start = 0;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 537803250ca9..e7a6958025ee 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2948,6 +2948,11 @@ static int ext4_da_do_write_end(struct address_space *mapping,
 	bool disksize_changed = false;
 	loff_t new_i_size;
 
+	if (unlikely(!folio_buffers(folio))) {
+		folio_unlock(folio);
+		folio_put(folio);
+		return -EIO;
+	}
 	/*
 	 * block_write_end() will mark the inode as dirty with I_DIRTY_PAGES
 	 * flag, which all that's needed to trigger page writeback.
-- 
2.35.3