From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794585631; b=oRJapt4gB00IVkiuCRv/zE6Jeut4B3/abtDvzhxrh1f0KiAwhm8tbhVbALXwW8Tccv1+ TNXfTTyMCnA3Gs5E+Mcydc64oe3rAH72XKqEpFV66APmSvKXRtuVUs5+t8fUjfIvEzhli TvWqhECxT2DME5+X97c3LGPUKTDh5xvqam8CECJDqrGvSRYxUoeM/BFGAQnaTs7OSPztL +cz/kwnCrDp+J+74baJzzIzl19ODANFWByyNsvTXSYLbhA9VXYjUEVsxqqkHTwOQU9L+1 r29FfMJV63PGnbeWdkdN8+KZ0EqtiaDN3DBgYGf8XZhzj6x3HHYduqdap8hXED60bMw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794585631; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=7vHS2QirwTEUa7+pve3pFDLZ//d1sblAY5Hw+yNfHJs=; b=hEFdQKjE1xo0iF8ZZ9q7xWAvNzZArqGAmuWrJn/ggiL39AhkhSZ/KCfBIUMXkG2fegj0 8cvFci2oJY1icgaG17Zvf8FLObADy4LY1jKu5o51V3t3up4oRr5BRUAJGdjfoTb6vH89Z 1hCDazkfxCFv6UAT7HxqLEb2prP8vt5Qw6tS/y2KzDv/J6LX9/qggW8oH2fCjX1OpdwhI UwQqlVT49FZzYte/nQC2xTAcnXlL/WhTMP3ghT9vdSOQBZFQgYaGiGS+pNPtxouUOLxLQ xoVCbrDY7l3yV+0eNB27l/eepejgz28hUvHtFLISwoNRJfpKt1XPfrRwhFm8NlfcN6A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="hybXIs+/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F4AC6070FEF; Fri, 13 Nov 2026 16:00:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=hybXIs+/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id D64B51F000C4; Fri, 13 Nov 2026 16:00:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794585631; bh=7vHS2QirwTEUa7+pve3pFDLZ//d1sblAY5Hw+yNfHJs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hybXIs+/CMDa8IQurBhzFbKqUryqsSBytgm8f94MFde+0sHKY5dQ/viAHmeW+HVrA bJXECzhtAJAKlyvldVyN+HimCFOcU9K9R9QmLLUITQjBcMyNOLBr5jlLfv301n9q+S 7zb5Qb0QC5ttxZg0FIwYDx9CCwF9rmJlfgSuJVBc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Joseph Qi , Andrew Morton , Heming Zhao , Mark Fasheh , Joel Becker , Sasha Levin Subject: [PATCH 7.3 251/507] ocfs2: do not index before the entry array when dividing an empty bucket Date: Fri, 13 Nov 2026 10:49:15 -0500 Message-ID: <20261113153803.069726263@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153753.358973689@linuxfoundation.org> References: <20261113153753.358973689@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joseph Qi [ Upstream commit 7133a0d0954c109f1764ebf8ab32d7e757a6c587 ] ocfs2_divide_xattr_bucket() appends an empty bucket carrying a sentinel hash when the source bucket has no divide position, taking that hash from xh_entries[start - 1]. ocfs2_xattr_find_divide_pos() returns count when every entry shares one hash, and its loop does not run at all for count < 2, so an empty bucket comes back with start == count == 0 and the read is xh_entries[-1]. That is outside the __counted_by_le(xh_count) bounds of xh_entries[] and lands on the header, so the value picked up is xh_count | xh_free_start << 16. One above it is written into the new bucket's xh_entries[0] and committed, which leaves a bucket whose first hash does not follow the bucket before it. ocfs2_xattr_bucket_find() binary searches on xh_entries[0], so the broken key hides the range the sentinel was meant to cover: getxattr() answers -ENODATA for an attribute that is stored, and an insert can go to the wrong bucket and leave two copies of a name. The cross cluster divide hands the same value back as a tree record's e_cpos, which then claims a hash range it does not cover. Read xh_entries[0] instead. The branch is only reached when every entry shares one hash, so for a non-empty bucket it holds the same value, and for an empty one it is the slot that carries the bucket key. An empty bucket reaches the divide from ocfs2_check_xattr_bucket_collision(), which reports no collision for one, through ocfs2_add_new_xattr_bucket() and ocfs2_extend_xattr_bucket(). It does not take a failed set to get there: a divide that finds no position is itself what leaves an empty sentinel bucket behind, and a later extend can pick it as the target. Link: https://lore.kernel.org/20261024151012.1059683-6-joseph.qi@linux.alibaba.com Fixes: 80bcaf3469b8 ("ocfs2/xattr: Proper hash collision handle in bucket division") Signed-off-by: Joseph Qi Signed-off-by: Andrew Morton Cc: Heming Zhao Cc: Mark Fasheh Cc: Joel Becker Cc: Signed-off-by: Sasha Levin --- fs/ocfs2/xattr.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 00f628e22d661..571c40f5dd447 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -5052,7 +5052,15 @@ static int ocfs2_divide_xattr_bucket(struct inode *inode, start = ocfs2_xattr_find_divide_pos(xh); if (start == count) { - xe = &xh->xh_entries[start-1]; + /* + * start == count means every entry shares one hash, so the + * first of them carries it too. An empty bucket has no + * entries[start - 1], but its entries[0] still carries the + * bucket key: either the hash ocfs2_xa_remove_entry() + * deliberately leaves behind, or the sentinel a previous + * divide wrote. + */ + xe = &xh->xh_entries[0]; /* * initialized a new empty bucket here. -- 2.53.0