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 2D2443438A6; Thu, 2 Jul 2026 16:48:12 +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=1783010893; cv=none; b=axzRpcI97dfNHpNPaYtuE2/GNdnkUI7SinoQz4xnm19BNdxWQJbrTEHPJCABU9wA5mQ9L49tsbpBHtFIQlXYcLaHWx2GxZb1xu5ii0rpauB+uB5Oyb2q5vBpepJ3fgrb1dtoQPZ7kclIrTeG2XVcQCf69sBGS8Z3ixU+MOFRYLw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783010893; c=relaxed/simple; bh=bZcPNc+5Cm+4QpL3lBXdaTihk3BvwjHAkpOKYUKJem4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EudOxnEKSONO8nm6HY4uEUfGqej7BWUOYrorkDW5quOBdvE55C2JYumK+de+kSEO/ZMeXvGig9j2lYMQ9ib4Ngx6Vg1vDYuBvW4CKT8Z+p/RLTdQ/Tgasd9cjJYRzisY9Bau+X0YYRJVqsDc11F4fLlupvseD+MfGlqZijxDn4A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Y/9+dkxu; 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="Y/9+dkxu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93F261F000E9; Thu, 2 Jul 2026 16:48:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1783010892; bh=dPiqUHLf0ymm74BL4hg+SGmX8zMa1dl+UeA81bFoJ3M=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Y/9+dkxudTrcwd+5Aei3tnTVy54CU0ylCNWeZJb0BqtmgLU4U5T5F9+C3IBC9xVIw 5zuScA9wMEOZPDkCdzQCHbaFWUvJmNDkWOq08gZRqNWOELVa87GCYDUUjcoCnWAGjk az5a9PsqicV7bNygV6YcDiOUDRCwyeunuxOa522E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Christian Brauner (Amutable)" , Quentin Schulz , Sasha Levin Subject: [PATCH 6.6 076/175] eventpoll: use hlist_is_singular_node() in __ep_remove() Date: Thu, 2 Jul 2026 18:19:37 +0200 Message-ID: <20260702155117.391018560@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260702155115.766838875@linuxfoundation.org> References: <20260702155115.766838875@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Brauner [ Upstream commit 3d9fd0abc94d8cd430cc7cd7d37ce5e5aae2cd2b ] Replace the open-coded "epi is the only entry in file->f_ep" check with hlist_is_singular_node(). Same semantics, and the helper avoids the head-cacheline access in the common false case. Link: https://patch.msgid.link/20260423-work-epoll-uaf-v1-1-2470f9eec0f5@kernel.org Signed-off-by: Christian Brauner (Amutable) Stable-dep-of: a6dc643c6931 ("eventpoll: fix ep_remove struct eventpoll / struct file UAF") Signed-off-by: Quentin Schulz Signed-off-by: Sasha Levin --- fs/eventpoll.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 8a556560a5b2f2..4f05d12a05031a 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -745,7 +745,7 @@ static bool __ep_remove(struct eventpoll *ep, struct epitem *epi, bool force) to_free = NULL; head = file->f_ep; - if (head->first == &epi->fllink && !epi->fllink.next) { + if (hlist_is_singular_node(&epi->fllink, head)) { /* See eventpoll_release() for details. */ WRITE_ONCE(file->f_ep, NULL); if (!is_file_epoll(file)) { -- 2.53.0