From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BB6D7CD5BB0 for ; Fri, 22 May 2026 15:30:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=VtekpR6cey4CtTWV4xkrXalV8L8MRvhbyb3+vKP/acc=; b=4punlZ3UXcwgN23+Gu4F+AD1Gy bp+gpu8vHVxiZywKQyziqT5pE6SsaxzhZatk2RGS6ZThPYkT5xrNltWFjUrzNaeKNafhLnxuTP8st qGI3OY0h91lWMK0p0ZKfMeKTeX9oyAHnnUkApXYdlcpP7ZTbe2Hh0+a5nJxVNKwODIeIoIDBPaySM oc8jieLi0kb0Yc2o/0b9N1KborLk8mGG0UjIkj9LtaHww+3DTTTs+tX9ZQY+TPrEq30TBBvyKqlmJ TMf+ZDO/ktDXxDB7w96Xg4Gln3NQWfaHj9mifpJqUXuZEiSCb5uEKOKk4X/VvkdPkhu1RFUyKWEoc JsIBqxNg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wQRpg-0000000BG5Q-0XHe; Fri, 22 May 2026 15:30:40 +0000 Received: from mail-vs1-xe32.google.com ([2607:f8b0:4864:20::e32]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wQRpd-0000000BG4t-2lo1 for linux-nvme@lists.infradead.org; Fri, 22 May 2026 15:30:38 +0000 Received: by mail-vs1-xe32.google.com with SMTP id ada2fe7eead31-63270abd14fso2468267137.1 for ; Fri, 22 May 2026 08:30:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1779463836; x=1780068636; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=VtekpR6cey4CtTWV4xkrXalV8L8MRvhbyb3+vKP/acc=; b=CXutb9zKKs4dS94Q4g4LjAKJV+NDLot18DKD5M9SRsoscDqIJ9hwT9fidz0fVA0uYi K/RUeNRw87LBKng5QzI8BH1nhN86zLXg8vf6KmJ3zy4zIIqaUG8D4bPmNEn12Jv8Y0Xf akgAG1n3Y3LuO1P0kIEcfagONWzX4hT1LJbj8jhyu9oBIiqfX2SXbyJ7RhLHNY9W089i hYCQVO/e0jS5qm1uxQnmMmplXIrj2IdjwJm8F5WjTVLwuXqsHkir6hIeUAltO8lmRS3+ 0hrv0yQIJp3v8IejZCBS0PgnhKKR/gE4SE1pF3iVFARM+wgxQ5dACfLbjLTViQYQZzCQ dhLg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779463836; x=1780068636; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=VtekpR6cey4CtTWV4xkrXalV8L8MRvhbyb3+vKP/acc=; b=MBR0tmHlY8gJkIY/sl9isuI7SEnqEBIy1SXfkAXKF6qrpw+yLYnHqXaCHo7PaDshGe WaJcnIwE9+10DtBmBal88Rkb4hZtLoZv82mfcJv1GZ0y8HgchG4GazPqYbfwtjcw3xGq y5oQN2Vq+DeE67ZgIbNI90OXfAR/6d9++Azr8nNJgLqJF95kuhLlAFFigvEDXXMU4Vba vFlj6/CnIyg5VdEYqj0kgToheH7VfeST+JyBpC2tuXZhdbMpfJVDlwkxcXVmhP2IjgFE jsMgy/LP5EpiQnyPEvQT2KYQ0X+V6LiKAv3KiZgOmvRl37rwxNxmhk/owyNWrO4XJfff Ycuw== X-Gm-Message-State: AOJu0YwjH9vYm7KcHuYhqljZ7bbTwzi9vXNRC4rXWA8Tm6uaL0oH7x1m E/nhmDJ7aaCvPSg6FVbF53lgFbWFTbKX2XltErIkhoOsfd09iWneCxNLp7ySUev86Rc= X-Gm-Gg: Acq92OEejOpXJ8gt+TSRyaESgJm/pVZ4JVw8Qxs9mlYknKD2gmQUgL+YxhTJa3LHPZs J9T+nHgnm2fFiydxjagBRUgqgmnsc0Ee8B6u0OSArhnWnQwkVPmFZ8veBlJac1FXXRtR4rBPRsC QbEWi7t5xebFx+telgJSPCEtrmpC2/n6oKK9MJwBEwUX5Vs6SPxaAzTFA/6qmlrU5DmD4cwKNuv BjVEO3kJPTdboUgNtfMiqyz9Wu0Wpu8BIjphvxnDFGyiSvZG253+HhdHbMFIoy9ptr/FPREnyBh bpJL4/p1eiJ96h/9xOWfgG3NOk9lc/TaZmjbKoKQ/Ixmyk8DJUeCxkkBb+qFpiDybWbV33bWdNU 5V4AZYxaC9U+Yh6JSx9TO4qhmc93yWXffoABa5Si5k0EfAWylG3Y7He133tPogiTUtyMcuQYVu9 2pzXx0tSpb5bquD23gvKzmL3S7sEOUITi7krfxXkDoJQ== X-Received: by 2002:a05:6102:4bc2:b0:634:a573:c097 with SMTP id ada2fe7eead31-67c79ebaac5mr2242680137.13.1779463836252; Fri, 22 May 2026 08:30:36 -0700 (PDT) Received: from syssplab.cs.fiu.edu (nat1.cs.fiu.edu. [131.94.134.89]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-96177c1a9e4sm1585228241.0.2026.05.22.08.30.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 May 2026 08:30:35 -0700 (PDT) From: Chao Shi To: Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Chao Shi , Sungwoo Kim , Dave Tian , Weidong Zhu Subject: [PATCH] nvme: reject completions for requests that are not in flight Date: Fri, 22 May 2026 11:30:34 -0400 Message-ID: <20260522153034.2168862-1-coshi036@gmail.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260522_083037_712317_FEF74F8B X-CRM114-Status: GOOD ( 13.70 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org nvme_find_rq() resolves a device-supplied command id to a request with blk_mq_tag_to_rq(), which returns whatever request last used that tag - possibly one that is no longer in flight (freed, or never dispatched and thus with a NULL rq->mq_hctx). Commit e7006de6c238 ("nvme: code command_id with a genctr for use-after-free validation") guards against this, but its generation counter is only 4 bits wide and can be matched by a malfunctioning or malicious device replaying command ids. The driver then completes a request that is not outstanding, dereferencing a NULL rq->mq_hctx or double-completing a command: Oops: general protection fault ... KASAN: null-ptr-deref RIP: blk_mq_complete_request_remote+0xe5/0xa80 block/blk-mq.c:1319 nvme_handle_cqe drivers/nvme/host/pci.c:1418 [inline] nvme_poll_cq drivers/nvme/host/pci.c:1449 nvme_irq drivers/nvme/host/pci.c:1463 Require the request to be in flight before completing it. The check uses the request state, so it also covers controllers with NVME_QUIRK_SKIP_CID_GEN. Found by FuzzNvme(Syzkaller with FEMU fuzzing framework). Acked-by: Sungwoo Kim Acked-by: Dave Tian Acked-by: Weidong Zhu Signed-off-by: Chao Shi --- drivers/nvme/host/nvme.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 9a5f28c5103c..3a525c1dc818 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -615,6 +615,17 @@ static inline struct request *nvme_find_rq(struct blk_mq_tags *tags, tag); return NULL; } + /* + * blk_mq_tag_to_rq() returns whatever request last used this tag, which + * may no longer be in flight if the device reports a bogus command id. + * Completing it would deref a NULL rq->mq_hctx or double-complete a + * command; the 4-bit genctr below only narrows the window. + */ + if (unlikely(blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)) { + dev_err(nvme_req(rq)->ctrl->device, + "completion for request %#x not in flight\n", tag); + return NULL; + } if (unlikely(nvme_genctr_mask(nvme_req(rq)->genctr) != genctr)) { dev_err(nvme_req(rq)->ctrl->device, "request %#x genctr mismatch (got %#x expected %#x)\n", -- 2.43.0