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 E129235208F; Tue, 26 Aug 2025 14:00:47 +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=1756216848; cv=none; b=I3lqMlz6RyG86kfvV+iOkqKtpWxzNdDbKtXi5XHljvHbfTuqUfr8djM753z6nEgecgmUsn7+8ZBML2vvaJCF4GVXo4CjlXE8QtvxFyxmyvpMyo4aSPTygh3hWJgMBpbsaptWy9Kk9ypaBdcJ+bneCsEk3LdGzYIYKP3nbW2cS6g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756216848; c=relaxed/simple; bh=ghC3mzWSkhiQdCv3/Q1GxYRWPHmCCgw3VhDaeN6LVS0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dVFBHTOPevVm84qwtWmTW1xn5Vccx37memj9fGEBmx2VeZIYihlokT1XZYSLP+8ABUEPG2oQhHz4ED/bRik4upMiMZB63A1ANgKBH+WNxJtLT/1PejsDnUtISJ/l3AlaTHvlgpQ8vLF14edO1KxZmsOmGN5zG5iaydTRq++tQwU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tJDiGyxD; 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="tJDiGyxD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73166C4CEF1; Tue, 26 Aug 2025 14:00:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756216847; bh=ghC3mzWSkhiQdCv3/Q1GxYRWPHmCCgw3VhDaeN6LVS0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tJDiGyxDCQi0IImxUXkbLZQxw+iq307VomJrZk2Z2LyUPI1P6kvXauGP2EGjkLtdh 1A3uydVfApz2N75Z7PnJnaRfX5hpdikZ3z3fpdudGhTCwrcY+L2M+pOAs+DOLe12wD b3Oxdk41a6ypDhUFX7B8tAw7nAdXw6zyl/h8cROc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiayi Li , Ulf Hansson Subject: [PATCH 5.15 564/644] memstick: Fix deadlock by moving removing flag earlier Date: Tue, 26 Aug 2025 13:10:55 +0200 Message-ID: <20250826111000.507311054@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110946.507083938@linuxfoundation.org> References: <20250826110946.507083938@linuxfoundation.org> User-Agent: quilt/0.68 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: Jiayi Li commit 99d7ab8db9d8230b243f5ed20ba0229e54cc0dfa upstream. The existing memstick core patch: commit 62c59a8786e6 ("memstick: Skip allocating card when removing host") sets host->removing in memstick_remove_host(),but still exists a critical time window where memstick_check can run after host->eject is set but before removing is set. In the rtsx_usb_ms driver, the problematic sequence is: rtsx_usb_ms_drv_remove: memstick_check: host->eject = true cancel_work_sync(handle_req) if(!host->removing) ... memstick_alloc_card() memstick_set_rw_addr() memstick_new_req() rtsx_usb_ms_request() if(!host->eject) skip schedule_work wait_for_completion() memstick_remove_host: [blocks indefinitely] host->removing = true flush_workqueue() [block] 1. rtsx_usb_ms_drv_remove sets host->eject = true 2. cancel_work_sync(&host->handle_req) runs 3. memstick_check work may be executed here <-- danger window 4. memstick_remove_host sets removing = 1 During this window (step 3), memstick_check calls memstick_alloc_card, which may indefinitely waiting for mrq_complete completion that will never occur because rtsx_usb_ms_request sees eject=true and skips scheduling work, memstick_set_rw_addr waits forever for completion. This causes a deadlock when memstick_remove_host tries to flush_workqueue, waiting for memstick_check to complete, while memstick_check is blocked waiting for mrq_complete completion. Fix this by setting removing=true at the start of rtsx_usb_ms_drv_remove, before any work cancellation. This ensures memstick_check will see the removing flag immediately and exit early, avoiding the deadlock. Fixes: 62c59a8786e6 ("memstick: Skip allocating card when removing host") Signed-off-by: Jiayi Li Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250804013604.1311218-1-lijiayi@kylinos.cn Signed-off-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman --- drivers/memstick/core/memstick.c | 1 - drivers/memstick/host/rtsx_usb_ms.c | 1 + 2 files changed, 1 insertion(+), 1 deletion(-) --- a/drivers/memstick/core/memstick.c +++ b/drivers/memstick/core/memstick.c @@ -548,7 +548,6 @@ EXPORT_SYMBOL(memstick_add_host); */ void memstick_remove_host(struct memstick_host *host) { - host->removing = 1; flush_workqueue(workqueue); mutex_lock(&host->lock); if (host->card) --- a/drivers/memstick/host/rtsx_usb_ms.c +++ b/drivers/memstick/host/rtsx_usb_ms.c @@ -812,6 +812,7 @@ static int rtsx_usb_ms_drv_remove(struct int err; host->eject = true; + msh->removing = true; cancel_work_sync(&host->handle_req); cancel_delayed_work_sync(&host->poll_card);