From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B7625241663; Mon, 27 Oct 2025 19:08:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761592108; cv=none; b=cvswyj7I5+RuMGyTHE+rF99d/fg2cLTQQXTctRBi/GChwG4n3+gWSZ6ko5u2i9K2awdMXkTQ57WNW+VDU8blnQU5j09cwCa6X5G2+3zdKofT4GqIbUephhlRqm1Vj4QCmT6u0gRAfUnZS1rKgbt1Yjmnc9EOOisHPHSjNSpeZjQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761592108; c=relaxed/simple; bh=X9m3Yb0uLG1YsU4wn2iYWwv2fi32m2sKCIYrCd7tBPY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pIyAhLLo1LVQf/nj2m+3luCnHcLoL4l7RSKkHlSuTIRK89O6BmE+y9vT+mbfFF2p6T42kqW7qZXfuoponPSxWFJx0t++8aE9qM7+sn+3ZV2zmGWUOw+5LtHlIdriuc2Aagn1aZphwmtLQ73gXhq6QCobzCkrxPIEoOoZBtxN1+Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=I74Noapj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="I74Noapj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2018EC4CEF1; Mon, 27 Oct 2025 19:08:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1761592108; bh=X9m3Yb0uLG1YsU4wn2iYWwv2fi32m2sKCIYrCd7tBPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I74NoapjR4/FnxDbpcEHUf5gTNA1Lbhc1saxY1F1KjnXhgxUF6VuWAt/SKJ7cSRGj zDa9TnF+8C87svZ6wPLWtVSboqaj0jgnYwfMU4tBpMf+sESbr8SUHHHV7qrevqr4dV VLRMNMq54oIfb0JTk3R9EaP5GVjTBtXpPjIAbk30= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Kuen-Han Tsai , Sasha Levin Subject: [PATCH 5.15 120/123] usb: gadget: f_acm: Refactor bind path to use __free() Date: Mon, 27 Oct 2025 19:36:40 +0100 Message-ID: <20251027183449.594487265@linuxfoundation.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251027183446.381986645@linuxfoundation.org> References: <20251027183446.381986645@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuen-Han Tsai [ Upstream commit 47b2116e54b4a854600341487e8b55249e926324 ] After an bind/unbind cycle, the acm->notify_req is left stale. If a subsequent bind fails, the unified error label attempts to free this stale request, leading to a NULL pointer dereference when accessing ep->ops->free_request. Refactor the error handling in the bind path to use the __free() automatic cleanup mechanism. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 Call trace: usb_ep_free_request+0x2c/0xec gs_free_req+0x30/0x44 acm_bind+0x1b8/0x1f4 usb_add_function+0xcc/0x1f0 configfs_composite_bind+0x468/0x588 gadget_bind_driver+0x104/0x270 really_probe+0x190/0x374 __driver_probe_device+0xa0/0x12c driver_probe_device+0x3c/0x218 __device_attach_driver+0x14c/0x188 bus_for_each_drv+0x10c/0x168 __device_attach+0xfc/0x198 device_initial_probe+0x14/0x24 bus_probe_device+0x94/0x11c device_add+0x268/0x48c usb_add_gadget+0x198/0x28c dwc3_gadget_init+0x700/0x858 __dwc3_set_mode+0x3cc/0x664 process_scheduled_works+0x1d8/0x488 worker_thread+0x244/0x334 kthread+0x114/0x1bc ret_from_fork+0x10/0x20 Fixes: 1f1ba11b6494 ("usb gadget: issue notifications from ACM function") Cc: stable@kernel.org Signed-off-by: Kuen-Han Tsai Link: https://lore.kernel.org/r/20250916-ready-v1-4-4997bf277548@google.com Signed-off-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20250916-ready-v1-4-4997bf277548@google.com Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_acm.c | 42 ++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 23 deletions(-) --- a/drivers/usb/gadget/function/f_acm.c +++ b/drivers/usb/gadget/function/f_acm.c @@ -11,12 +11,15 @@ /* #define VERBOSE_DEBUG */ +#include #include #include #include #include #include +#include + #include "u_serial.h" @@ -612,6 +615,7 @@ acm_bind(struct usb_configuration *c, st struct usb_string *us; int status; struct usb_ep *ep; + struct usb_request *request __free(free_usb_request) = NULL; /* REVISIT might want instance-specific strings to help * distinguish instances ... @@ -629,7 +633,7 @@ acm_bind(struct usb_configuration *c, st /* allocate instance-specific interface IDs, and patch descriptors */ status = usb_interface_id(c, f); if (status < 0) - goto fail; + return status; acm->ctrl_id = status; acm_iad_descriptor.bFirstInterface = status; @@ -638,40 +642,38 @@ acm_bind(struct usb_configuration *c, st status = usb_interface_id(c, f); if (status < 0) - goto fail; + return status; acm->data_id = status; acm_data_interface_desc.bInterfaceNumber = status; acm_union_desc.bSlaveInterface0 = status; acm_call_mgmt_descriptor.bDataInterface = status; - status = -ENODEV; - /* allocate instance-specific endpoints */ ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_in_desc); if (!ep) - goto fail; + return -ENODEV; acm->port.in = ep; ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_out_desc); if (!ep) - goto fail; + return -ENODEV; acm->port.out = ep; ep = usb_ep_autoconfig(cdev->gadget, &acm_fs_notify_desc); if (!ep) - goto fail; + return -ENODEV; acm->notify = ep; /* allocate notification */ - acm->notify_req = gs_alloc_req(ep, - sizeof(struct usb_cdc_notification) + 2, - GFP_KERNEL); - if (!acm->notify_req) - goto fail; + request = gs_alloc_req(ep, + sizeof(struct usb_cdc_notification) + 2, + GFP_KERNEL); + if (!request) + return -ENODEV; - acm->notify_req->complete = acm_cdc_notify_complete; - acm->notify_req->context = acm; + request->complete = acm_cdc_notify_complete; + request->context = acm; /* support all relevant hardware speeds... we expect that when * hardware is dual speed, all bulk-capable endpoints work at @@ -688,7 +690,9 @@ acm_bind(struct usb_configuration *c, st status = usb_assign_descriptors(f, acm_fs_function, acm_hs_function, acm_ss_function, acm_ss_function); if (status) - goto fail; + return status; + + acm->notify_req = no_free_ptr(request); dev_dbg(&cdev->gadget->dev, "acm ttyGS%d: %s speed IN/%s OUT/%s NOTIFY/%s\n", @@ -698,14 +702,6 @@ acm_bind(struct usb_configuration *c, st acm->port.in->name, acm->port.out->name, acm->notify->name); return 0; - -fail: - if (acm->notify_req) - gs_free_req(acm->notify, acm->notify_req); - - ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status); - - return status; } static void acm_unbind(struct usb_configuration *c, struct usb_function *f)