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 C70D6352FFF; Tue, 26 Aug 2025 14:40:45 +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=1756219245; cv=none; b=eS+YnGLK17kMvypaPHhVhYJsqeE0UBHFlVAIczh+4VDVrBDIVUyL5U7RUtaY6Wsc+s+6IjhHcGB0fJjyFGIQ9SNPrMUHlF2gXTZWy0glMbARJrIjU/da56iEzNuEZljjR1Z00WyQ8kttheM08gozq//GzphfIJU6UVoW9fzz3OM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756219245; c=relaxed/simple; bh=MaFayi0eLwJNH6Sf6GDDo6L1kF3u9UbgRv9MN2JLuU4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=R2FCWAgWB+UJaJIk1cz8NBmTnCX3MZY1qbOxtqE1gJb9VSVNRb/GPwSfmHEh/YUygx6sDCgLMbB0JbvcOzw/3Ua3QV4CC6pbq103hzdQwQ7woVgruBzUF27QSK7xJ1+OL48kdv+QjC6YpQPT1xlw0YJX9dhY4tc0TmHSD+kZxFE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FAaaOoc6; 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="FAaaOoc6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0892BC4CEF1; Tue, 26 Aug 2025 14:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756219245; bh=MaFayi0eLwJNH6Sf6GDDo6L1kF3u9UbgRv9MN2JLuU4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FAaaOoc6c/CbC4KkEHRmWRdoyCMS7Sd/ZzcNMY5SIDASEM1epXkQoyiPnRjtWaIdE CEPAso+LA6OEjoEhS7iSz8EFlfuWDmO6St0gTxA13v4RPk2FVYYsDDEurK0QsNs3Ln QaWyk6kRyDZ08ugz1d2UnXvtG4YYQtxCq+GRaXV0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiayi Li , Ulf Hansson Subject: [PATCH 5.4 308/403] memstick: Fix deadlock by moving removing flag earlier Date: Tue, 26 Aug 2025 13:10:34 +0200 Message-ID: <20250826110915.322264013@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110905.607690791@linuxfoundation.org> References: <20250826110905.607690791@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 5.4-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 @@ -550,7 +550,6 @@ 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);