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=1794274028; b=juLWLCLWV4Lhh4CYrbmDM06hJk5HVtTVguB6plhHIDsX9rtKqJOIUqiqCkqtvGHTnqAE 5vZbX5iq4VDkhijTuVkasaPiSgMTITjfkv23y8NB2i5yOuywK0rZxTdHIj1u09u0rtZ2y bs/1Bes7jTG8RcZH6gzlq1HzBvB222wYyjPHIxEKg9LxZcph0rTGELsuUZh+lTupoIq5H /XqxpdZQXexbBCgJlwPDty5rm9gZgE4JoEmzitPGufE/MtgStck+GXlWhfdT27T/VXVRv I9PdNlfR5qNS3YIZAzevOqEcSBH51YoBgMpdBknpQWW1hfWqHQqRipG5uGzEpfzey+g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794274028; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=9p7Z66X9TrGlo6571feshgLEv8ui841p6JSUFtxD89A=; b=3mHdlW5RFErVsWVVH9gC+6MJKdqjrKcNBMFnbCKpvA6BjHJ6bzNxUfmMxAYeMHGcEgVF yXpIiyoR98vLSPx+zESZBD159p53wqGuqMiGkKqNGIHEs+IzW92Cg6abvomWGhj48GDTn 2wxL34tyrCnWO8ekcoTnyqJA1ZW/YwhhuvQeSVXq+S7Aj/k5Et8BiIsgGBwUG3Gferz0g TMJ0Ar5qyY6OrEffzOVpoxUEONbKbfZYJ+Jed4E8hsG+PQHN+XKNKxQYM4+c0zvUMg8bL 5H/iMmszgwSLUrAQxtdYMUZKa0Qxau7FiRQq6UyJpMBgclfv7/HrD4MI0uo7q+PVDvA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Z3c68bEC; 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 8652D606A330 for ; Tue, 10 Nov 2026 01:27:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Z3c68bEC Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB1A91F008A4; Tue, 10 Nov 2026 01:27:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794274028; bh=9p7Z66X9TrGlo6571feshgLEv8ui841p6JSUFtxD89A=; h=From:To:Cc:Subject:Date; b=Z3c68bECp6RLcICng2NAvEBszlP9bsfqy57v+kqGZ2gxeSQMYBlhvpY5bgAwNzXNf gMN9XHMA10A4T+0ByuHS6OX5ZFQ1ir0B/+cExaG6xjX8CbAgy+gcVFk446np48qp76 bwvvg+oTdVpTm0Tfmsx+lROkl1BcGuT4SSIx4x5ywMbbqU4zGeqIFzOwwqckZvvYne 1ZCFmRh2yfNy/AnofsY3b2C0mKhryIpdw9v8uXQyZkiTg4Uj1f614INKIb/Kef6tXq p1qHKw0+jOPfUrarhFQexBVQZOv0CvwtsxFLhMYCmuSwvdAN81t+MrGZq8Ctlw5Lgs N1nCwsEnBCvEQ== From: Sasha Levin To: joseph.qi@linux.alibaba.com, akpm@linux-foundation.org, heming.zhao@suse.com, mark@fasheh.com, jlbec@evilplan.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] ocfs2: do not read the entry array of an empty xattr bucket" failed to apply to 5.10-stable tree Date: Mon, 9 Nov 2026 20:27:06 -0500 Message-ID: <20261109202706-failed-5.10-e8de099f2958@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.10-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 . 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-5.10.y git checkout FETCH_HEAD git cherry-pick -x e8de099f2958c84aa23186c5481e69f7ffd39355 # git commit -s git send-email --to '' --in-reply-to '20261109202706-failed-5.10-e8de099f2958@kernel.org' --subject-prefix 'PATCH 5.10.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From e8de099f2958c84aa23186c5481e69f7ffd39355 Mon Sep 17 00:00:00 2001 From: Joseph Qi Date: Sat, 24 Oct 2026 23:10:10 +0800 Subject: [PATCH] ocfs2: do not read the entry array of an empty xattr bucket ocfs2_check_xattr_bucket_collision() decides whether splitting a bucket can make room by comparing the hash being inserted against the first and the last entry. xh_count comes off disk and is never checked, and a bucket is allowed to hold no entries: ocfs2_xa_remove_entry() keeps the last slot when it removes the only one, so that an empty bucket still carries the hash it is keyed by. xh_count then reads back as 0 while xh_entries[0] is still meaningful, and the second comparison indexes xh_entries[-1]. That is outside the __counted_by_le(xh_count) bounds of xh_entries[] and lands on the header. An entry is 16 bytes and xe_name_hash is its first field, so the value read is xh_count | xh_free_start << 16. It stays inside the block, but the answer is arbitrary, and for an empty bucket it says there is no collision, so a new bucket gets added on the strength of it. An empty bucket holds no entries to collide with. Return before reading the array. One way to reach the test with an empty bucket is a set that removes the bucket's only entry during cleanup and then fails for space again, since it is that second -ENOSPC which calls this. Growing a value past OCFS2_XATTR_INLINE_SIZE is the easy route: the cluster allocation fails, the "!orig_clusters" arm of ocfs2_xa_cleanup_value_truncate() removes the entry, and although the "growing" caller does set ctxt->set_abort, only ocfs2_xattr_block_set() and __ocfs2_xattr_set_handle() look at it, so ocfs2_xattr_set_entry_index_block() goes straight on to the collision check. This sits on commit a9ea8b397864 ("ocfs2: use the stored hash when checking xattr bucket collision"), which gave the collision check its two argument form and is marked for 6.2 and later. The read fixed here is present in the three argument version too, but a tree without that commit needs the hunk adapted by hand. Link: https://lore.kernel.org/20261024151012.1059683-5-joseph.qi@linux.alibaba.com Fixes: 012255961c9e ("ocfs2: Enable xattr set in index btree") Signed-off-by: Joseph Qi Signed-off-by: Andrew Morton Cc: Heming Zhao Cc: Mark Fasheh Cc: Joel Becker Cc: --- fs/ocfs2/xattr.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 2c069029cef73..3a16b4a36d9ae 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -6061,11 +6061,20 @@ static int ocfs2_check_xattr_bucket_collision(struct ocfs2_xattr_bucket *bucket, u32 name_hash) { struct ocfs2_xattr_header *xh = bucket_xh(bucket); + u16 count = le16_to_cpu(xh->xh_count); + + /* + * An empty bucket keeps the hash of the entry that was removed in + * xh_entries[0] so that it can still be found, but it holds no + * entries to collide with. + */ + if (!count) + return 0; if (name_hash != le32_to_cpu(xh->xh_entries[0].xe_name_hash)) return 0; - if (xh->xh_entries[le16_to_cpu(xh->xh_count) - 1].xe_name_hash == + if (xh->xh_entries[count - 1].xe_name_hash == xh->xh_entries[0].xe_name_hash) { mlog(ML_ERROR, "Too much hash collision in xattr bucket %llu, " "hash = %u\n", -- 2.53.0