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=1794046855; b=RPT8c9IUP+P1+la1DB1oSXyOv/VsxRr2SGWJZ92oTyONFvSOXs9pj0gbu0ELQyxABj4X GdgFH0nCM/M2mbGaBFYXuZJ5GJTqKzbFwg/2IC7T1uMJfGaq6/3fy8yI3z+In+eXX3Iv5 U5Gipd4NEO/yX9C17ak7JQzp2Xdy7wu1Tw24EA3UtaRX8McdWis+7mcuMgdl/ATcbJPyl cwJm4tcB4TBm1VSZBqKLrJENNCmSJ/WfzXNzRNBsJUOndRx19ZLrB3HsBb3dszo+f/xP3 N7RCr9XEYuvU8VQSZtixlpZyh59zOk9gjZrRLfSEujce9dTXKtUmA5gQdOIR4KxEruw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794046855; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=BB5uRvvDKv4Z6dCAskfy6AOr/0l5IL93QfpZJ9tNE6E=; b=EDLioXZ4JSaQ9pgcf+cKxH3gPOgYWkbSGjdlNJvHfkJm/TwFVNRn6um7+8/0xCDE845u 3Xr/LH11gI5+Gr74VFiZoTDb6FQiCv17sfQ3E4O2D3veHlJ3JEzaVjpMf6FOPg14YYOCj SCLQ6qV3Cc7BoN027PlJg+Hvjd/9BR8AmRMRgYPjKb77VhZlGPJ7Ap3acglzuwZjzdzwA Pw6kPw8RoIuEGYglFQDypjuPcXRqrC309VMzIo72oevLXqqpFpwVxB1T2ooecQOgHY7sT aIFl6EEsEWmwalPQx2Z4+CS2/kMePUBubUGvOePwFcY6c8EEjs2T2EokC4e0Jz4YUkQ== 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=JN68b4MM; 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 77EF8606A330 for ; Sat, 7 Nov 2026 10:20:55 +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=JN68b4MM Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE6441F0089F; Sat, 7 Nov 2026 10:20:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794046855; bh=BB5uRvvDKv4Z6dCAskfy6AOr/0l5IL93QfpZJ9tNE6E=; h=From:To:Cc:Subject:Date; b=JN68b4MM/AYDD/r9P9vXqD921ZF5TOGcLvUp+8juNAhcskk7Xw/GV0QjKXmpGKIy8 S6dt9WnybSBLmGgpr61f0jdUhWLIFR04pgx2KuEnd3PWPRj3C9y/1+OKalskv2ZJsH Ql2zSUYBPqV/zeMg6PJgmQtQDU8Nbxpn+47HjU6J+4D2fIyVteqVwy1sSbOPEt4yKe dnZ6m5AeN24IAExSnkPHVwqfCasxhWhq/CIQXPaFu009I3vznnGzlGbKwpOpd5LJrw 1TSzmWCmos41jbMnc99qLR/M859WAN3HmK3u3McXSwpm4TYm3RKMeQBzYyl/N6cLNB kdzc05Q6GiKCA== From: Sasha Levin To: gyf161023@gmail.com, ekansh.gupta@oss.qualcomm.com, srini@kernel.org, gregkh@linuxfoundation.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] misc: fastrpc: fix double-free in fastrpc_map_attach() error path" failed to apply to 6.12-stable tree Date: Sat, 7 Nov 2026 05:20:53 -0500 Message-ID: <20261107052053-failed-6.12-09fa66ec1b48@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 6.12-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-6.12.y git checkout FETCH_HEAD git cherry-pick -x 09fa66ec1b4896ab841da085ca58b6433f28f07f # git commit -s git send-email --to '' --in-reply-to '20261107052053-failed-6.12-09fa66ec1b48@kernel.org' --subject-prefix 'PATCH 6.12.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 09fa66ec1b4896ab841da085ca58b6433f28f07f Mon Sep 17 00:00:00 2001 From: Yifei Gao Date: Fri, 2 Oct 2026 11:12:19 +0100 Subject: [PATCH] misc: fastrpc: fix double-free in fastrpc_map_attach() error path map->table is assigned right after dma_buf_map_attachment_unlocked() succeeds. The two failure checks that follow, the len > map->size test and, where subsystem VMIDs are configured, a failed qcom_scm_assign_mem(), jump to map_err with map->table already set. map_err manually calls dma_buf_detach() and dma_buf_put() and then falls through to fastrpc_map_put(). Since that change the error path tail is fastrpc_map_put() -> fastrpc_free_map(), and fastrpc_free_map() already unmaps, detaches and puts the dma-buf whenever map->table is set. The two operations therefore run twice: the second dma_buf_put() drops an extra reference on map->buf, and dma_buf_unmap_attachment_unlocked() dereferences the map->attach already freed by the manual dma_buf_detach(). kref_init() sets the refcount to 1 with no intervening get, so the final fastrpc_map_put() frees the map synchronously and the redundant cleanup is deterministic. The len > map->size branch is reachable by an unprivileged process via FASTRPC_IOCTL_MEM_MAP with an fd whose dma-buf is smaller than the requested length, before any DSP invocation. Route both map->table-is-set failure branches to get_err instead of map_err, so fastrpc_free_map() is the single owner of the unmap/detach/put sequence. map_err is retained for the dma_buf_map_attachment_unlocked() failure, which is reached with map->table still NULL and an attachment that fastrpc_free_map() will not clean up, so its dma_buf_detach()/dma_buf_put() must still run manually. Fixes: 334f1a1cbe03 ("misc: fastrpc: Use fastrpc_map_put in fastrpc_map_create on fail") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Yifei Gao Reviewed-by: Ekansh Gupta Signed-off-by: Srinivas Kandagatla Link: https://patch.msgid.link/20261002101220.1084101-2-srinivas.kandagatla@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/fastrpc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 53ad9a3f10699..904f538f0dd0e 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -927,7 +927,7 @@ static int fastrpc_map_attach(struct fastrpc_user *fl, int fd, dev_dbg(sess->dev, "Bad size passed len 0x%llx map size 0x%llx\n", len, map->size); err = -EINVAL; - goto map_err; + goto get_err; } map->va = sg_virt(map->table->sgl); map->len = len; @@ -950,7 +950,7 @@ static int fastrpc_map_attach(struct fastrpc_user *fl, int fd, dev_err(sess->dev, "Failed to assign memory with dma_addr %pad size 0x%llx err %d\n", &map->dma_addr, map->len, err); - goto map_err; + goto get_err; } } spin_lock(&fl->lock); -- 2.53.0