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 9775D1E5B95 for ; Sat, 23 Aug 2025 15:57:08 +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=1755964628; cv=none; b=Eazk86CKaJtoO22yvp17STBr+xGXU1cvUPNVH+w5Ihy40qD55b5yne/RJMwTRwhdAA1nUbZUvZJ0kxLFRK80MkPWOasmyQ6K4vWHhKd0u4lR7FB9ERZ8YfMvw1REGorG5CluHjc3hogCuK22+D4DzT3n8LJBHva3fbvwbnP6exc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755964628; c=relaxed/simple; bh=MF8niugkwHjavn4jWdLjVYjkmKnCFyxkEwu8W+R05V8=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=VgQ34uDOq7Gj+fCdT22VNFWfjhOSJthiv+UIuealqQ+OU/Jpc4MYrRBj6KIkynZVj9MVlp4s7sLImzJxjBGBeg9e3fhZWVP/BZSXmnlKln8mCCylQAG+Hm1OIfUb7Cp6QmrMbMG3yhVwrUVNA2p4JfZ8Os3KAxftLudWxLZwECE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=T4eZ6u6D; 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="T4eZ6u6D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 167BEC4CEE7; Sat, 23 Aug 2025 15:57:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755964628; bh=MF8niugkwHjavn4jWdLjVYjkmKnCFyxkEwu8W+R05V8=; h=Subject:To:Cc:From:Date:From; b=T4eZ6u6D4VINgaKydIVE8FtqlIwGfi5aMyBRZ0VJXX0xJjp70kOYnqb3LZROCqbA9 5225B0Zgu2eXou0o4WPeg+0FIwyWEbjGOD4ENb2AZ0qK6q1AE+VQVQi2dRF+L2lO+Y JHVAYt0chq2AAYaCp9aXMjpqbp2s55iAhTt7Y5Wk= Subject: FAILED: patch "[PATCH] usb: xhci: Fix slot_id resource race conflict" failed to apply to 6.6-stable tree To: WeitaoWang-oc@zhaoxin.com,gregkh@linuxfoundation.org,mathias.nyman@linux.intel.com Cc: From: Date: Sat, 23 Aug 2025 17:57:05 +0200 Message-ID: <2025082305-paddle-refute-2bd7@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 2eb03376151bb8585caa23ed2673583107bb5193 # git commit -s git send-email --to '' --in-reply-to '2025082305-paddle-refute-2bd7@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 2eb03376151bb8585caa23ed2673583107bb5193 Mon Sep 17 00:00:00 2001 From: Weitao Wang Date: Tue, 19 Aug 2025 15:58:43 +0300 Subject: [PATCH] usb: xhci: Fix slot_id resource race conflict xHC controller may immediately reuse a slot_id after it's disabled, giving it to a new enumerating device before the xhci driver freed all resources related to the disabled device. In such a scenario, device-A with slot_id equal to 1 is disconnecting while device-B is enumerating, device-B will fail to enumerate in the follow sequence. 1.[device-A] send disable slot command 2.[device-B] send enable slot command 3.[device-A] disable slot command completed and wakeup waiting thread 4.[device-B] enable slot command completed with slot_id equal to 1 and wakeup waiting thread 5.[device-B] driver checks that slot_id is still in use (by device-A) in xhci_alloc_virt_device, and fail to enumerate due to this conflict 6.[device-A] xhci->devs[slot_id] set to NULL in xhci_free_virt_device To fix driver's slot_id resources conflict, clear xhci->devs[slot_id] and xhci->dcbba->dev_context_ptrs[slot_id] pointers in the interrupt context when disable slot command completes successfully. Simultaneously, adjust function xhci_free_virt_device to accurately handle device release. [minor smatch warning and commit message fix -Mathias] Cc: stable@vger.kernel.org Fixes: 7faac1953ed1 ("xhci: avoid race between disable slot command and host runtime suspend") Signed-off-by: Weitao Wang Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20250819125844.2042452-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index 92bb84f8132a..b3a59ce1b3f4 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -704,8 +704,7 @@ static int xhci_enter_test_mode(struct xhci_hcd *xhci, if (!xhci->devs[i]) continue; - retval = xhci_disable_slot(xhci, i); - xhci_free_virt_device(xhci, i); + retval = xhci_disable_and_free_slot(xhci, i); if (retval) xhci_err(xhci, "Failed to disable slot %d, %d. Enter test mode anyway\n", i, retval); diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 07289333a1e8..81eaad87a3d9 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -865,21 +865,20 @@ int xhci_alloc_tt_info(struct xhci_hcd *xhci, * will be manipulated by the configure endpoint, allocate device, or update * hub functions while this function is removing the TT entries from the list. */ -void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id) +void xhci_free_virt_device(struct xhci_hcd *xhci, struct xhci_virt_device *dev, + int slot_id) { - struct xhci_virt_device *dev; int i; int old_active_eps = 0; /* Slot ID 0 is reserved */ - if (slot_id == 0 || !xhci->devs[slot_id]) + if (slot_id == 0 || !dev) return; - dev = xhci->devs[slot_id]; - - xhci->dcbaa->dev_context_ptrs[slot_id] = 0; - if (!dev) - return; + /* If device ctx array still points to _this_ device, clear it */ + if (dev->out_ctx && + xhci->dcbaa->dev_context_ptrs[slot_id] == cpu_to_le64(dev->out_ctx->dma)) + xhci->dcbaa->dev_context_ptrs[slot_id] = 0; trace_xhci_free_virt_device(dev); @@ -920,8 +919,9 @@ void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id) dev->udev->slot_id = 0; if (dev->rhub_port && dev->rhub_port->slot_id == slot_id) dev->rhub_port->slot_id = 0; - kfree(xhci->devs[slot_id]); - xhci->devs[slot_id] = NULL; + if (xhci->devs[slot_id] == dev) + xhci->devs[slot_id] = NULL; + kfree(dev); } /* @@ -962,7 +962,7 @@ static void xhci_free_virt_devices_depth_first(struct xhci_hcd *xhci, int slot_i out: /* we are now at a leaf device */ xhci_debugfs_remove_slot(xhci, slot_id); - xhci_free_virt_device(xhci, slot_id); + xhci_free_virt_device(xhci, vdev, slot_id); } int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id, diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index ecd757d482c5..4f8f5aab109d 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1592,7 +1592,8 @@ static void xhci_handle_cmd_enable_slot(int slot_id, struct xhci_command *comman command->slot_id = 0; } -static void xhci_handle_cmd_disable_slot(struct xhci_hcd *xhci, int slot_id) +static void xhci_handle_cmd_disable_slot(struct xhci_hcd *xhci, int slot_id, + u32 cmd_comp_code) { struct xhci_virt_device *virt_dev; struct xhci_slot_ctx *slot_ctx; @@ -1607,6 +1608,10 @@ static void xhci_handle_cmd_disable_slot(struct xhci_hcd *xhci, int slot_id) if (xhci->quirks & XHCI_EP_LIMIT_QUIRK) /* Delete default control endpoint resources */ xhci_free_device_endpoint_resources(xhci, virt_dev, true); + if (cmd_comp_code == COMP_SUCCESS) { + xhci->dcbaa->dev_context_ptrs[slot_id] = 0; + xhci->devs[slot_id] = NULL; + } } static void xhci_handle_cmd_config_ep(struct xhci_hcd *xhci, int slot_id) @@ -1856,7 +1861,7 @@ static void handle_cmd_completion(struct xhci_hcd *xhci, xhci_handle_cmd_enable_slot(slot_id, cmd, cmd_comp_code); break; case TRB_DISABLE_SLOT: - xhci_handle_cmd_disable_slot(xhci, slot_id); + xhci_handle_cmd_disable_slot(xhci, slot_id, cmd_comp_code); break; case TRB_CONFIG_EP: if (!cmd->completion) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 47151ca527bf..0e03691f03bf 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -3932,8 +3932,7 @@ static int xhci_discover_or_reset_device(struct usb_hcd *hcd, * Obtaining a new device slot to inform the xHCI host that * the USB device has been reset. */ - ret = xhci_disable_slot(xhci, udev->slot_id); - xhci_free_virt_device(xhci, udev->slot_id); + ret = xhci_disable_and_free_slot(xhci, udev->slot_id); if (!ret) { ret = xhci_alloc_dev(hcd, udev); if (ret == 1) @@ -4090,7 +4089,7 @@ static void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev) xhci_disable_slot(xhci, udev->slot_id); spin_lock_irqsave(&xhci->lock, flags); - xhci_free_virt_device(xhci, udev->slot_id); + xhci_free_virt_device(xhci, virt_dev, udev->slot_id); spin_unlock_irqrestore(&xhci->lock, flags); } @@ -4139,6 +4138,16 @@ int xhci_disable_slot(struct xhci_hcd *xhci, u32 slot_id) return 0; } +int xhci_disable_and_free_slot(struct xhci_hcd *xhci, u32 slot_id) +{ + struct xhci_virt_device *vdev = xhci->devs[slot_id]; + int ret; + + ret = xhci_disable_slot(xhci, slot_id); + xhci_free_virt_device(xhci, vdev, slot_id); + return ret; +} + /* * Checks if we have enough host controller resources for the default control * endpoint. @@ -4245,8 +4254,7 @@ int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev) return 1; disable_slot: - xhci_disable_slot(xhci, udev->slot_id); - xhci_free_virt_device(xhci, udev->slot_id); + xhci_disable_and_free_slot(xhci, udev->slot_id); return 0; } @@ -4382,8 +4390,7 @@ static int xhci_setup_device(struct usb_hcd *hcd, struct usb_device *udev, dev_warn(&udev->dev, "Device not responding to setup %s.\n", act); mutex_unlock(&xhci->mutex); - ret = xhci_disable_slot(xhci, udev->slot_id); - xhci_free_virt_device(xhci, udev->slot_id); + ret = xhci_disable_and_free_slot(xhci, udev->slot_id); if (!ret) { if (xhci_alloc_dev(hcd, udev) == 1) xhci_setup_addressable_virt_dev(xhci, udev); diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index a20f4e7cd43a..85d5b964bf1e 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1791,7 +1791,7 @@ void xhci_dbg_trace(struct xhci_hcd *xhci, void (*trace)(struct va_format *), /* xHCI memory management */ void xhci_mem_cleanup(struct xhci_hcd *xhci); int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags); -void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id); +void xhci_free_virt_device(struct xhci_hcd *xhci, struct xhci_virt_device *dev, int slot_id); int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id, struct usb_device *udev, gfp_t flags); int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *udev); void xhci_copy_ep0_dequeue_into_input_ctx(struct xhci_hcd *xhci, @@ -1888,6 +1888,7 @@ void xhci_reset_bandwidth(struct usb_hcd *hcd, struct usb_device *udev); int xhci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev, struct usb_tt *tt, gfp_t mem_flags); int xhci_disable_slot(struct xhci_hcd *xhci, u32 slot_id); +int xhci_disable_and_free_slot(struct xhci_hcd *xhci, u32 slot_id); int xhci_ext_cap_init(struct xhci_hcd *xhci); int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup);