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 61EC79468 for ; Fri, 19 Apr 2024 04:18:08 +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=1713500289; cv=none; b=Qx69O2FzVFXUITzT14tqyYYNR4qnXh+dbHzUZ8WHGoZpSMNBYD/HpqGn0kl0nrRpJR0Ho0WJlz9/z9X/iRkNxzWpVg2HfLjmpS8vIpyoCTs4smdRlhvkhBI2A9y3QYeF8IX/CB1Gm/ZvvAH220Blmi40+5eBFKdVAtuA9jGg+Yg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713500289; c=relaxed/simple; bh=Z1GxcNShqB7XjrKgRjxJrDPpPtYOMOCiBldCNHlQm84=; h=From:To:Cc:Subject:References:Date:In-Reply-To:Message-ID: MIME-Version:Content-Type; b=bml1+Is+UjvQmhIUdqRDkvc1+RvGi+UStPNgztkSls9iKasbIQ2jrE5/uQxaFSnr4fuxd+yQz2Zg93iNLyeRm04rTO836b9RfM10xmtpgxKbnjz51aXYgnkesPGra5J4ToICTPOGzZCKBkciiOAeNhUBjfUBcMBR9pcuElK14gw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P7KU0WYe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P7KU0WYe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D1EAC072AA; Fri, 19 Apr 2024 04:18:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1713500288; bh=Z1GxcNShqB7XjrKgRjxJrDPpPtYOMOCiBldCNHlQm84=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=P7KU0WYe3nl+AduFRsoDjvM/628wFQ0c+5CS5g7L3aiHi/zMFqLM6R33kcgPIaCPQ kneklFUZ2ePotb8XkXvP1a8/IVlZd9ViAAZw2bxMNllBHES3HDKx6MxhDUqjssV6fP xif28L1VFK1LEJPS5MSIgX+b+nZJLKuBKbEIVDm6156sxGYc7cb5dQKtbogMLjI60G ChQK/PN/ous+6bXUdcluPcKJqngSaH3SvZ9oPZUwIjhOVC2huDk5c74AL9VWe0DWCz G9qcVMRwfIiLMMYFC3dKUlLkbxvZCvkSpWx1uFaOjwsVItEC6KU7c+f14Lwk+Lg0k0 ooJpA+eTw9rTg== From: Kalle Valo To: Baochen Qiang Cc: , Subject: Re: [PATCH] wifi: ath12k: fix kernel crash during resume References: <20240419034034.2842-1-quic_bqiang@quicinc.com> Date: Fri, 19 Apr 2024 07:18:05 +0300 In-Reply-To: <20240419034034.2842-1-quic_bqiang@quicinc.com> (Baochen Qiang's message of "Fri, 19 Apr 2024 11:40:34 +0800") Message-ID: <87cyqmhtoi.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Baochen Qiang writes: > Currently during resume, QMI target memory is not properly handled, resulting > in kernel crash in case DMA remap is not supported: > > BUG: Bad page state in process kworker/u16:54 pfn:36e80 > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x36e80 > page dumped because: nonzero _refcount > Call Trace: > bad_page > free_page_is_bad_report > __free_pages_ok > __free_pages > dma_direct_free > dma_free_attrs > ath12k_qmi_free_target_mem_chunk > ath12k_qmi_msg_mem_request_cb > > The reason is: > Once ath12k module is loaded, firmware sends memory request to host. In case > DMA remap not supported, ath12k refuses the first request due to failure in > allocating with large segment size: > > ath12k_pci 0000:04:00.0: qmi firmware request memory request > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 7077888 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 8454144 > ath12k_pci 0000:04:00.0: qmi dma allocation failed (7077888 B type 1), will try later with small size > ath12k_pci 0000:04:00.0: qmi delays mem_request 2 > ath12k_pci 0000:04:00.0: qmi firmware request memory request > > Later firmware comes back with more but small segments and allocation > succeeds: > > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 262144 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 > ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 65536 > ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 > > Now ath12k is working. If suspend is triggered, firmware will be reloaded > during resume. As same as before, firmware requests two large segments at > first. In ath12k_qmi_msg_mem_request_cb() segment count and size are > assigned: > > ab->qmi.mem_seg_count == 2 > ab->qmi.target_mem[0].size == 7077888 > ab->qmi.target_mem[1].size == 8454144 > > Then allocation failed like before and ath12k_qmi_free_target_mem_chunk() > is called to free all allocated segments. Note the first segment is skipped > because its v.addr is cleared due to allocation failure: > > chunk->v.addr = dma_alloc_coherent() > > Also note that this leaks that segment because it has not been freed. > > While freeing the second segment, a size of 8454144 is passed to > dma_free_coherent(). However remember that this segment is allocated at > the first time firmware is loaded, before suspend. So its real size is > 524288, much smaller than 8454144. As a result kernel found we are freeing > some memory which is in use and thus crashed. > > So one possible fix would be to free those segments during suspend. This > works because with them freed, ath12k_qmi_free_target_mem_chunk() does > nothing: all segment addresses are NULL so dma_free_coherent() is not called. > > But note that ath11k has similar logic but never hits this issue. Reviewing > code there shows the luck comes from QMI memory reuse logic. So the decision > is to port it to ath12k. Like in ath11k, the crash is avoided by adding > prev_size to target_mem_chunk structure and caching real segment size in it, > then prev_size instead of current size is passed to dma_free_coherent(), > no unexpected memory is freed now. > > Also reuse m3 buffer. > > Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4 > Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3 > > Fixes: 64430ddfb132 ("wifi: ath12k: support suspend/resume") > Signed-off-by: Baochen Qiang To keep git bisect clean should this patch be applied before applying the suspend patchset? No need resend or anything, just checking what should be the correct order. -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches