From nobody Mon Sep 28 10:02:39 2026 Received: from mail-24425.protonmail.ch (mail-24425.protonmail.ch [109.224.244.25]) (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 421D236F905; Mon, 24 Aug 2026 02:32:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=109.224.244.25 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787538764; cv=none; b=lHxl4gneUlWd+joC4DaHit2CHg5XVo1TsM3Zc6fgb7pMEMlOq0zE79+wny6zXrK6hO655FBKp8EvukQj3sm5SebSLa1V1r53GHLeRtwhqANrD8hMApn6ivSeZEZ3OTf8gCWiRrJhylsb9slZpgaklVZHrvNgeRJx7Zkqa082N4Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787538764; c=relaxed/simple; bh=NwkZ0WftKFL0fiULLEYQmShV0iQtCEYdG4MbEtd5z+s=; h=Date:To:From:Cc:Subject:Message-ID:MIME-Version:Content-Type; b=ZQIzmYY20HGu9JhT/I+8H00b35FSUYbC7cgTpDQpqa/kZbGLhLmz0Uigx9Kvb3JD6teSsT9nJlaihA3EjJMNsd2hWJFPYI2D3DJvZjiIA0rJ1d3p4uanruuc0wI/QeiS3hkP2mcQvLWsQSA5gR/RcCcGmccShrOEDODjoKjHkC4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=proton.me; spf=pass smtp.mailfrom=proton.me; dkim=pass (2048-bit key) header.d=proton.me header.i=@proton.me header.b=FBuyvhMS; arc=none smtp.client-ip=109.224.244.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=proton.me Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=proton.me Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=proton.me header.i=@proton.me header.b="FBuyvhMS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1787538746; x=1787797946; bh=CO0P/4spPJKMxUAFueCKPG9jpVdFqvTvazGX83BR+GA=; h=Date:To:From:Cc:Subject:Message-ID:Feedback-ID:From:To:Cc:Date: Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector; b=FBuyvhMSvNA94G3vYCk/wfVeLew1gbFas2tQrUqncV6AFuXxP2ZdHRIIMqYDrcd/P RWAS76Ts6kosxrbfapm7bf63M5qUQ5W45yKnNevt7yx9d3rFOjZ/YdDdW3Jk1oHbh7 JFZLA8BJxlnnXZBCCJuESTTtNV+/Jil47H1JMlEssxRtZWEYvIQMTquQL2bjM71vrh 3iVKwIXC1hwKQguUvAq02iBwhfu+3SqWPfoLO9/zyAfXe5wAd0k+7ksxMIsOLVufD2 ipGS/KQXklWF8tsVEjMmuYNnYa/wsWbIrqQMrxy6cC+cww4ydlykBNNNIXe4wLaxBs +9ovlEwzpcciw== Date: Mon, 24 Aug 2026 02:32:20 +0000 To: "alexander.usyskin@intel.com" , "arnd@arndb.de" , "gregkh@linuxfoundation.org" From: nirbhayykumarr@proton.me Cc: "w@1wt.eu" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH v2] misc: mei: fix race condition between client teardown and read completion Message-ID: Feedback-ID: 172828574:user:proton X-Pm-Message-ID: 0bb16a8d6da00a8767e572a7db202b2a2aa83d2f 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 Content-Type: text/plain; charset="utf-8" In mei_release(), a host client is torn down upon close(). During this teardown sequence, mei_cl_disconnect() is invoked, which releases dev->device_lock while waiting for the firmware response. If an in-flight read request was previously submitted, an incoming completion interrupt processed concurrently by the MEI interrupt handler can add a completed callback into cl->rd_completed via mei_cl_add_rd_completed(). Because mei_cl_flush_queues(cl, NULL) was invoked before mei_cl_unlink(cl), an incoming completion callback can slip into cl->rd_completed after the flush has completed but before the client is unlinked from dev->file_list. When mei_cl_unlink() is subsequently called, the invariant check at drivers/misc/mei/client.c:698 triggers: WARN_ON(!list_empty(&cl->rd_completed) || !list_empty(&cl->rd_pending) || !list_empty(&cl->link)); Call trace: WARNING: CPU: 2 PID: 5056 at drivers/misc/mei/client.c:698 mei_cl_unlink+= 0xaa/0x140 [mei] RIP: 0010:mei_cl_unlink+0xaa/0x140 [mei] Call Trace: mei_release+0x202/0x270 [mei] __fput+0x105/0x2e0 __x64_sys_close+0x90/0x140 do_syscall_64+0xaa/0x660 entry_SYSCALL_64_after_hwframe+0x77/0x7f Immediately following mei_cl_unlink(), mei_release() calls kfree(cl). If any remaining or deferred callback references the freed client, a use-after-free occurs. Fix this by flushing queues after unlinking the client from dev->file_list inside mei_cl_unlink(), preventing concurrent IRQ completions from populating the client's completed queue during teardown. Fixes: f35fe5f47ed0 ("mei: add a vtag map for each client") Helped-by: Willy Tarreau Helped-by: Greg Kroah-Hartman Signed-off-by: Nirbhay Kumar Cc: stable@vger.kernel.org --- v2: - Removed redundant Reported-by tag. - Added Fixes tag tracing back to the commit that introduced the race wind= ow. - Added Helped-by tags to credit Willy and Greg for guidance. - Sent inline without attachment as requested. drivers/misc/mei/client.c | 2 ++ drivers/misc/mei/main.c | 1 - 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c index 643b003..38b5792 100644 --- a/drivers/misc/mei/client.c +++ b/drivers/misc/mei/client.c @@ -695,6 +695,8 @@ int mei_cl_unlink(struct mei_cl *cl) cl->state =3D MEI_FILE_UNINITIALIZED; cl->writing_state =3D MEI_IDLE; + mei_cl_flush_queues(cl, NULL); + WARN_ON(!list_empty(&cl->rd_completed) || !list_empty(&cl->rd_pending) || !list_empty(&cl->link)); diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c index 4fbf0b3..9e14ab4 100644 --- a/drivers/misc/mei/main.c +++ b/drivers/misc/mei/main.c @@ -148,7 +148,6 @@ static int mei_release(struct inode *inode, struct file= *file) goto out; } - mei_cl_flush_queues(cl, NULL); cl_dbg(dev, cl, "removing\n"); mei_cl_unlink(cl); --=20 2.55.0