From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3330831A7EA; Fri, 9 Jan 2026 11:50:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767959402; cv=none; b=NCuN0ReiXy30+uKLgNHxUuxfqCCdZ6Z17RXIB0Uzd7Ic3AwTkOev4ECthw76/Tf8kGNB1jQJDlQvF66/IDClwYcWDTnoUV2DAZ+1/7AFxcCYl2j5lAPFtOCqi0OYFSXziUE4gdWN9pqI1ygPwiTEPT6lz/rE3v6ro8oI4ALtZtE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767959402; c=relaxed/simple; bh=Tpz/mohIkgHpTh8D1w67sJX8K0/UMuDfvRXwpwGb76I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Qdebg5KJNp+zwD4pYd4fK4E4rojXXQoQt+kv+WtbgnKgVE6hKcWNwwPPemaZiEs0VEvV5ORToTFFG6XrIHSGElaMppHNrKn4YoeAlmH/pUWoYdx+ckuxDmsSQ/O/2SCrqUl5hRZgmJgI8uA0nQLhiXgAlXj7Z2OSKVhMr0pMyAo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Xugoz/RD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Xugoz/RD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 617DFC4CEF1; Fri, 9 Jan 2026 11:50:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767959401; bh=Tpz/mohIkgHpTh8D1w67sJX8K0/UMuDfvRXwpwGb76I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xugoz/RDfgIXWBWLV+UfQUuwUSkGT3cN0o4hLqh/vkmyslx+suIzYAZCZRtxm7EBX yYicMgdr3eWrRLDVtDf/MurVGCAqyDd86+dKRgkhRuKAEhMhYKrH3IFN5Rj0cyxQ0L LolT14pJBlghwojWtjErgbycZfFWNZXYGo+VlHfI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+f3185be57d7e8dda32b8@syzkaller.appspotmail.com, stable@kernel.org, Deepanshu Kartikey , Theodore Tso Subject: [PATCH 6.6 008/737] ext4: refresh inline data size before write operations Date: Fri, 9 Jan 2026 12:32:27 +0100 Message-ID: <20260109112134.305335190@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112133.973195406@linuxfoundation.org> References: <20260109112133.973195406@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Deepanshu Kartikey commit 892e1cf17555735e9d021ab036c36bc7b58b0e3b upstream. The cached ei->i_inline_size can become stale between the initial size check and when ext4_update_inline_data()/ext4_create_inline_data() use it. Although ext4_get_max_inline_size() reads the correct value at the time of the check, concurrent xattr operations can modify i_inline_size before ext4_write_lock_xattr() is acquired. This causes ext4_update_inline_data() and ext4_create_inline_data() to work with stale capacity values, leading to a BUG_ON() crash in ext4_write_inline_data(): kernel BUG at fs/ext4/inline.c:1331! BUG_ON(pos + len > EXT4_I(inode)->i_inline_size); The race window: 1. ext4_get_max_inline_size() reads i_inline_size = 60 (correct) 2. Size check passes for 50-byte write 3. [Another thread adds xattr, i_inline_size changes to 40] 4. ext4_write_lock_xattr() acquires lock 5. ext4_update_inline_data() uses stale i_inline_size = 60 6. Attempts to write 50 bytes but only 40 bytes actually available 7. BUG_ON() triggers Fix this by recalculating i_inline_size via ext4_find_inline_data_nolock() immediately after acquiring xattr_sem. This ensures ext4_update_inline_data() and ext4_create_inline_data() work with current values that are protected from concurrent modifications. This is similar to commit a54c4613dac1 ("ext4: fix race writing to an inline_data file while its xattrs are changing") which fixed i_inline_off staleness. This patch addresses the related i_inline_size staleness issue. Reported-by: syzbot+f3185be57d7e8dda32b8@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=f3185be57d7e8dda32b8 Cc: stable@kernel.org Signed-off-by: Deepanshu Kartikey Message-ID: <20251020060936.474314-1-kartikey406@gmail.com> Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inline.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -413,7 +413,12 @@ static int ext4_prepare_inline_data(hand return -ENOSPC; ext4_write_lock_xattr(inode, &no_expand); - + /* + * ei->i_inline_size may have changed since the initial check + * if other xattrs were added. Recalculate to ensure + * ext4_update_inline_data() validates against current capacity. + */ + (void) ext4_find_inline_data_nolock(inode); if (ei->i_inline_off) ret = ext4_update_inline_data(handle, inode, len); else