From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C452B373BF2; Sat, 12 Sep 2026 12:38:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789216711; cv=none; b=CjV+7CCXJad3YgZ58FlBbJwq6mg3V56rWODdO32Nhg96MEVQS6qNlTJuCyKIrLrYciQrKYCOjA5CQrKtuluWI1QOTjBU4PLgHXyGYb4bG+AZ2ElsqrQ/eyR/yqR9qWgSx32GAVIY1TvNsR27JWsQ+LwkfLNuTH0/Dj9WjbF1RBE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789216711; c=relaxed/simple; bh=ANu17FUVisPXOYHHbAYv7PJbTUyCRcqU22V6dTNHBgM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=j+lX+TOA6tqI89fwci9Th+XkLpMQxNumilofEaKh6HoCggGjX8Wtai+0BnQGw7NHny9EGmzMEv5KkL3FGZkYLZ5C+pWpF2cKCeAPjXrV2gEItWTsAFcPQp3z29z0zpV6UcLZpbDvH7B33wS4EgjP4UYG7lbR5EKrSV0zLJXGSn0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ADc+J+/q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ADc+J+/q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7CFC1F000FF; Sat, 12 Sep 2026 12:38:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789216710; bh=I6rX0fU8+DARci7xts5XtUFzCSfTaP18capOvV8CPDU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ADc+J+/q+tNkc3C5oEvS+pu1wx5mtvBx2ne+zLMr6KkpRgYcH22MKNjXrX5+x0AZr N2W0Js0PAlJg1+5qMb09YU+niW7JP1zbhXIMziaX6NC6L2uKtJkFJujdOR2n3Ol0zi THFKJP/U1xlV8EcwJb8M4T28/86J8sWYLs4cf2Z8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexei Starovoitov , Shakeel Butt , Harry Yoo , Vlastimil Babka , Sasha Levin Subject: [PATCH 6.12 0750/1376] slab: Reuse first bit for OBJEXTS_ALLOC_FAIL Date: Sat, 12 Sep 2026 08:52:56 +0200 Message-ID: <20260912065624.257684514@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexei Starovoitov [ Upstream commit 7612833192d56af86061de8ab51989b75daf5b0d ] Since the combination of valid upper bits in slab->obj_exts with OBJEXTS_ALLOC_FAIL bit can never happen, use OBJEXTS_ALLOC_FAIL == (1ull << 0) as a magic sentinel instead of (1ull << 2) to free up bit 2. Signed-off-by: Alexei Starovoitov Acked-by: Shakeel Butt Reviewed-by: Harry Yoo Signed-off-by: Vlastimil Babka Stable-dep-of: 4c6eb712a91f ("wifi: ath12k: fix stride mismatch in mac_phy_caps_parse()") Signed-off-by: Sasha Levin --- include/linux/memcontrol.h | 10 ++++++++-- mm/slub.c | 2 +- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e1b41554a5fb3..e4c24c94b9ef0 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -344,17 +344,23 @@ enum page_memcg_data_flags { __NR_MEMCG_DATA_FLAGS = (1UL << 2), }; +#define __OBJEXTS_ALLOC_FAIL MEMCG_DATA_OBJEXTS #define __FIRST_OBJEXT_FLAG __NR_MEMCG_DATA_FLAGS #else /* CONFIG_MEMCG */ +#define __OBJEXTS_ALLOC_FAIL (1UL << 0) #define __FIRST_OBJEXT_FLAG (1UL << 0) #endif /* CONFIG_MEMCG */ enum objext_flags { - /* slabobj_ext vector failed to allocate */ - OBJEXTS_ALLOC_FAIL = __FIRST_OBJEXT_FLAG, + /* + * Use bit 0 with zero other bits to signal that slabobj_ext vector + * failed to allocate. The same bit 0 with valid upper bits means + * MEMCG_DATA_OBJEXTS. + */ + OBJEXTS_ALLOC_FAIL = __OBJEXTS_ALLOC_FAIL, /* the next bit after the last actual flag */ __NR_OBJEXTS_FLAGS = (__FIRST_OBJEXT_FLAG << 1), }; diff --git a/mm/slub.c b/mm/slub.c index f3868bad83dbb..620e31869c624 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1958,7 +1958,7 @@ static inline void handle_failed_objexts_alloc(unsigned long obj_exts, * objects with no tag reference. Mark all references in this * vector as empty to avoid warnings later on. */ - if (obj_exts & OBJEXTS_ALLOC_FAIL) { + if (obj_exts == OBJEXTS_ALLOC_FAIL) { unsigned int i; for (i = 0; i < objects; i++) -- 2.53.0