From nobody Tue Dec 2 02:06:38 2025 Received: from outboundhk.mxmail.xiaomi.com (outboundhk.mxmail.xiaomi.com [207.226.244.123]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C19DB26463A; Thu, 20 Nov 2025 12:34:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=207.226.244.123 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763642077; cv=none; b=CncbBPapRFqOcV9de+28pICVBEYl2PYcAOUbksmQBwnUpFbTiDiUwWIKZoLLfXoBbPkhR6Kj/10anx88ZqE/4B+9b40Amw4vLHHob46/iYNE3Q7Gi+WOTbT8igQvNPyY8Z179Xpbwne5FyCiD2NVmodR5L8QIbj6BRzmwmOeb9A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763642077; c=relaxed/simple; bh=uASkiBThjg0+2aydI15+rppeNYNlJb+ZepyqZt3ACiI=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=RSZ99YFkYNevR0AKjbwhGx9jGpZQFsfIgZW66EXS2UwhDR1jbkW+ppxQUyLMYuUR1B5n2DGx4E6Pw9xYlctASdftWLMfnTliZ31bkc6WPn6/TbSU2FpjTVQSz+C2/SnaI3Ev9jkZYXAPItNLsZzIkkgbVViQNEMh1GgOSi2sQJc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=xiaomi.com; spf=pass smtp.mailfrom=xiaomi.com; arc=none smtp.client-ip=207.226.244.123 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=xiaomi.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=xiaomi.com X-CSE-ConnectionGUID: I9S4tjiGQ7WW3GG6Ca6ONQ== X-CSE-MsgGUID: JD2+mL9rQqCt5e1vO6uGnA== X-IronPort-AV: E=Sophos;i="6.20,213,1758556800"; d="scan'208";a="158953641" From: guhuinan To: Greg Kroah-Hartman , Oliver Neukum , Alan Stern CC: , , , , , Yu Chen , Owen Gu , Michal Pecio Subject: [PATCH v4] usb: uas: fix urb unmapping issue when the uas device is remove during ongoing data transfer Date: Thu, 20 Nov 2025 20:33:36 +0800 Message-ID: <20251120123336.3328-1-guhuinan@xiaomi.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BJ-MBX19.mioffice.cn (10.237.8.139) To BJ-MBX05.mioffice.cn (10.237.8.125) Content-Type: text/plain; charset="utf-8" From: Owen Gu When a UAS device is unplugged during data transfer, there is a probability of a system panic occurring. The root cause is an access to an invalid memory address during URB callback handling. Specifically, this happens when the dma_direct_unmap_sg() function is called within the usb_hcd_unmap_urb_for_dma() interface, but the sg->dma_address field is 0 and the sg data structure has already been freed. The SCSI driver sends transfer commands by invoking uas_queuecommand_lck() in uas.c, using the uas_submit_urbs() function to submit requests to USB. Within the uas_submit_urbs() implementation, three URBs (sense_urb, data_urb, and cmd_urb) are sequentially submitted. Device removal may occur at any point during uas_submit_urbs execution, which may result in URB submission failure. However, some URBs might have been successfully submitted before the failure, and uas_submit_urbs will return the -ENODEV error code in this case. The current error handling directly calls scsi_done(). In the SCSI driver, this eventually triggers scsi_complete() to invoke scsi_end_request() for releasing the sgtable. The successfully submitted URBs, when being unlinked to giveback, call usb_hcd_unmap_urb_for_dma() in hcd.c, leading to exceptions during sg unmapping operations since the sg data structure has already been freed. This patch modifies the error condition check in the uas_submit_urbs() function. When a UAS device is removed but one or more URBs have already been successfully submitted to USB, it avoids immediately invoking scsi_done() and save the cmnd to devinfo->cmnd array. If the successfully submitted URBs is completed before devinfo->resetting being set, then the scsi_done() function will be called within uas_try_complete() after all pending URB operations are finalized. Otherwise, the scsi_done() function will be called within uas_zap_pending(), which is executed after usb_kill_anchored_urbs(). The error handling only takes effect when uas_queuecommand_lck() calls uas_submit_urbs() and returns the error value -ENODEV . In this case, the device is disconnected, and the flow proceeds to uas_disconnect(), where uas_zap_pending() is invoked to call uas_try_complete(). Fixes: eb2a86ae8c54 ("USB: UAS: fix disconnect by unplugging a hub") Cc: stable@vger.kernel.org Signed-off-by: Yu Chen Signed-off-by: Owen Gu Acked-by: Oliver Neukum --- v4: Add the fix tag, cc stable and acked-by tag v3: Add some commit message. v2: Upon uas_submit_urbs() returning -ENODEV despite successful URB submission, the cmnd is added to the devinfo->cmnd array before exiting uas_queuecommand_lck(). https://lore.kernel.org/linux-usb/20251015153157.11870-1-guhuinan@xiaomi.co= m/ v1: https://lore.kernel.org/linux-usb/20250930045309.21588-1-guhuinan@xiaom= i.com/ --- --- drivers/usb/storage/uas.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c index 03043d567fa1..02fe411567fa 100644 --- a/drivers/usb/storage/uas.c +++ b/drivers/usb/storage/uas.c @@ -698,6 +698,10 @@ static int uas_queuecommand_lck(struct scsi_cmnd *cmnd) * of queueing, no matter how fatal the error */ if (err =3D=3D -ENODEV) { + if (cmdinfo->state & (COMMAND_INFLIGHT | DATA_IN_URB_INFLIGHT | + DATA_OUT_URB_INFLIGHT)) + goto out; + set_host_byte(cmnd, DID_NO_CONNECT); scsi_done(cmnd); goto zombie; @@ -711,6 +715,7 @@ static int uas_queuecommand_lck(struct scsi_cmnd *cmnd) uas_add_work(cmnd); } =20 +out: devinfo->cmnd[idx] =3D cmnd; zombie: spin_unlock_irqrestore(&devinfo->lock, flags); --=20 2.43.0