From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-177.mta0.migadu.com (out-177.mta0.migadu.com [91.218.175.177]) (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 63E437E9 for ; Sat, 24 May 2025 13:53:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748094804; cv=none; b=pzWJt32lvKf7KKEMyuFdsY5vO0VbVcu+emmHX5x5P/XzMx6AgDTqzulDi6Gd2fnrklIrAmrlpCu4Pk3zLahQJjG/8FsM3ay3uDQTDFUT2JSaH2R3PpC1lwk/2PeA3549sXf7acjQWKIWlYkKcllUvuxbS1NHhGM9jsdn8onyRAs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748094804; c=relaxed/simple; bh=azLNJMoJgHs7cJEbtjwSPshfeaRBs+GRrvXkxggzSEw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gUy3+FnqPeNxK611/umkGzm8xMQI0B3PM667PGHNNOp9SkA91HLMIWRm2gRdUCPjjmMCNijLoBYWmJu06nbHzkNdbl+ExbQEbRLenx6LKmq5qyuxJ0dFK4T2NoNVuBlmlAH98PTuHdaOGuVEEeBN2pf5AQjlwoBuHnjvcGArhSE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=bp0aVTOY; arc=none smtp.client-ip=91.218.175.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="bp0aVTOY" Message-ID: <6d0c8757-274d-4148-9f40-8e752e846987@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1748094798; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=C5nhc8hWoT/wQNGyULW2ojsB0ysmV6JLeIcNI4KAIN0=; b=bp0aVTOYL1B053VfGu7HS4gts2RoEhRjc9PGHNRNjie88/v4XDHZ2ywkrOqjOObic7Uv+M tqyTTRxAgLNqlSso8/ymsGwrzTZITmeveiQCrgyyhpwfwUBfLSVScfEkyw07imFtstMlHq MdDJfR6mRdt7/5huXQsqxu6cXs8A1S8= Date: Sat, 24 May 2025 15:53:15 +0200 Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH for-next v1] RDMA/core: Avoid hmm_dma_map_alloc() for virtual DMA devices To: Daisuke Matsuda , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, leon@kernel.org, jgg@ziepe.ca, zyjzyj2000@gmail.com Cc: hch@infradead.org References: <20250523184701.11004-1-dskmtsd@gmail.com> <95b1875c-fe87-4941-9242-551fb9546ccc@gmail.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Zhu Yanjun In-Reply-To: <95b1875c-fe87-4941-9242-551fb9546ccc@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 在 2025/5/24 15:15, Daisuke Matsuda 写道: > > On 2025/05/24 16:52, Zhu Yanjun wrote: >> 在 2025/5/24 9:31, Zhu Yanjun 写道: >>> 在 2025/5/23 20:47, Daisuke Matsuda 写道: >>>> Drivers such as rxe, which use virtual DMA, must not call into the DMA >>>> mapping core since they lack physical DMA capabilities. Otherwise, a >>>> NULL >>>> pointer dereference is observed as shown below. This patch ensures >>>> the RDMA >>>> core handles virtual and physical DMA paths appropriately. >>>> >>>> This fixes the following kernel oops: >>>> >>>>   BUG: kernel NULL pointer dereference, address: 00000000000002fc >>>>   #PF: supervisor read access in kernel mode >>>>   #PF: error_code(0x0000) - not-present page >>>>   PGD 1028eb067 P4D 1028eb067 PUD 105da0067 PMD 0 >>>>   Oops: Oops: 0000 [#1] SMP NOPTI >>>>   CPU: 3 UID: 1000 PID: 1854 Comm: python3 Tainted: G W >>>> 6.15.0-rc1+ #11 PREEMPT(voluntary) >>>>   Tainted: [W]=WARN >>>>   Hardware name: Trigkey Key N/Key N, BIOS KEYN101 09/02/2024 >>>>   RIP: 0010:hmm_dma_map_alloc+0x25/0x100 >>>>   Code: 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 >>>> d6 49 c1 e6 0c 41 55 41 54 53 49 39 ce 0f 82 c6 00 00 00 49 89 fc >>>> 87 fc 02 00 00 20 0f 84 af 00 00 00 49 89 f5 48 89 d3 49 89 cf >>>>   RSP: 0018:ffffd3d3420eb830 EFLAGS: 00010246 >>>>   RAX: 0000000000001000 RBX: ffff8b727c7f7400 RCX: 0000000000001000 >>>>   RDX: 0000000000000001 RSI: ffff8b727c7f74b0 RDI: 0000000000000000 >>>>   RBP: ffffd3d3420eb858 R08: 0000000000000000 R09: 0000000000000000 >>>>   R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 >>>>   R13: 00007262a622a000 R14: 0000000000001000 R15: ffff8b727c7f74b0 >>>>   FS:  00007262a62a1080(0000) GS:ffff8b762ac3e000(0000) >>>> knlGS:0000000000000000 >>>>   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>>   CR2: 00000000000002fc CR3: 000000010a1f0004 CR4: 0000000000f72ef0 >>>>   PKRU: 55555554 >>>>   Call Trace: >>>>    >>>>    ib_init_umem_odp+0xb6/0x110 [ib_uverbs] >>>>    ib_umem_odp_get+0xf0/0x150 [ib_uverbs] >>>>    rxe_odp_mr_init_user+0x71/0x170 [rdma_rxe] >>>>    rxe_reg_user_mr+0x217/0x2e0 [rdma_rxe] >>>>    ib_uverbs_reg_mr+0x19e/0x2e0 [ib_uverbs] >>>>    ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xd9/0x150 [ib_uverbs] >>>>    ib_uverbs_cmd_verbs+0xd19/0xee0 [ib_uverbs] >>>>    ? mmap_region+0x63/0xd0 >>>>    ? __pfx_ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0x10/0x10 >>>> [ib_uverbs] >>>>    ib_uverbs_ioctl+0xba/0x130 [ib_uverbs] >>>>    __x64_sys_ioctl+0xa4/0xe0 >>>>    x64_sys_call+0x1178/0x2660 >>>>    do_syscall_64+0x7e/0x170 >>>>    ? syscall_exit_to_user_mode+0x4e/0x250 >>>>    ? do_syscall_64+0x8a/0x170 >>>>    ? do_syscall_64+0x8a/0x170 >>>>    ? syscall_exit_to_user_mode+0x4e/0x250 >>>>    ? do_syscall_64+0x8a/0x170 >>>>    ? syscall_exit_to_user_mode+0x4e/0x250 >>>>    ? do_syscall_64+0x8a/0x170 >>>>    ? do_user_addr_fault+0x1d2/0x8d0 >>>>    ? irqentry_exit_to_user_mode+0x43/0x250 >>>>    ? irqentry_exit+0x43/0x50 >>>>    ? exc_page_fault+0x93/0x1d0 >>>>    entry_SYSCALL_64_after_hwframe+0x76/0x7e >>>>   RIP: 0033:0x7262a6124ded >>>>   Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 >>>> 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 >>>> <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00 >>>>   RSP: 002b:00007fffd08c3960 EFLAGS: 00000246 ORIG_RAX: >>>> 0000000000000010 >>>>   RAX: ffffffffffffffda RBX: 00007fffd08c39f0 RCX: 00007262a6124ded >>>>   RDX: 00007fffd08c3a10 RSI: 00000000c0181b01 RDI: 0000000000000007 >>>>   RBP: 00007fffd08c39b0 R08: 0000000014107820 R09: 00007fffd08c3b44 >>>>   R10: 000000000000000c R11: 0000000000000246 R12: 00007fffd08c3b44 >>>>   R13: 000000000000000c R14: 00007fffd08c3b58 R15: 0000000014107960 >>>>    >>>> >>>> Fixes: 1efe8c0670d6 ("RDMA/core: Convert UMEM ODP DMA mapping to >>>> caching IOVA and page linkage") >>>> Closes: https://lore.kernel.org/ >>>> all/3e8f343f-7d66-4f7a-9f08-3910623e322f@gmail.com/ >>>> Signed-off-by: Daisuke Matsuda >>>> --- >>>>   drivers/infiniband/core/device.c   | 24 ++++++++++++++++++++++++ >>>>   drivers/infiniband/core/umem_odp.c |  6 +++--- >>>>   include/rdma/ib_verbs.h            | 12 ++++++++++++ >>>>   3 files changed, 39 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/ >>>> core/device.c >>>> index b4e3e4beb7f4..8be4797c66ec 100644 >>>> --- a/drivers/infiniband/core/device.c >>>> +++ b/drivers/infiniband/core/device.c >>>> @@ -2864,6 +2864,30 @@ int ib_dma_virt_map_sg(struct ib_device *dev, >>>> struct scatterlist *sg, int nents) >>>>       return nents; >>>>   } >>>>   EXPORT_SYMBOL(ib_dma_virt_map_sg); >>>> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map, >>>> +              size_t nr_entries, size_t dma_entry_size) >>>> +{ >>>> +    if (!(nr_entries * PAGE_SIZE / dma_entry_size)) >>>> +        return -EINVAL; >>>> + >>>> +    map->dma_entry_size = dma_entry_size; >>>> +    map->pfn_list = kvcalloc(nr_entries, sizeof(*map->pfn_list), >>>> +                 GFP_KERNEL | __GFP_NOWARN); >>>> +    if (!map->pfn_list) >>>> +        return -ENOMEM; >>>> + >>>> +    map->dma_list = kvcalloc(nr_entries, sizeof(*map->dma_list), >>>> +                 GFP_KERNEL | __GFP_NOWARN); >>>> +    if (!map->dma_list) >>>> +        goto err_dma; >>>> + >>>> +    return 0; >>>> + >>>> +err_dma: >>>> +    kvfree(map->pfn_list); >>>> +    return -ENOMEM; >>>> +} >>>> +EXPORT_SYMBOL(ib_dma_virt_map_alloc); >>>>   #endif /* CONFIG_INFINIBAND_VIRT_DMA */ >>>>   static const struct rdma_nl_cbs >>>> ibnl_ls_cb_table[RDMA_NL_LS_NUM_OPS] = { >>>> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/ >>>> infiniband/ core/umem_odp.c >>>> index 51d518989914..aa03f3fc84d0 100644 >>>> --- a/drivers/infiniband/core/umem_odp.c >>>> +++ b/drivers/infiniband/core/umem_odp.c >>>> @@ -75,9 +75,9 @@ static int ib_init_umem_odp(struct ib_umem_odp >>>> *umem_odp, >>>>       if (unlikely(end < page_size)) >>>>           return -EOVERFLOW; >>>> -    ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map, >>>> -                (end - start) >> PAGE_SHIFT, >>>> -                1 << umem_odp->page_shift); >>>> +    ret = ib_dma_map_alloc(dev, &umem_odp->map, >>>> +                   (end - start) >> PAGE_SHIFT, >>>> +                   1 << umem_odp->page_shift); >>>>       if (ret) >>>>           return ret; >>>> diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h >>>> index b06a0ed81bdd..10813f348b99 100644 >>>> --- a/include/rdma/ib_verbs.h >>>> +++ b/include/rdma/ib_verbs.h >>>> @@ -36,6 +36,7 @@ >>>>   #include >>>>   #include >>>>   #include >>>> +#include >>>>   #include >>>>   #include >>>>   #include >>>> @@ -4221,6 +4222,17 @@ static inline void >>>> ib_dma_unmap_sg_attrs(struct ib_device *dev, >>>>                      dma_attrs); >>>>   } >>>> +int ib_dma_virt_map_alloc(struct device *dev, struct hmm_dma_map *map, >>>> +              size_t nr_entries, size_t dma_entry_size); >>>> +static inline int ib_dma_map_alloc(struct ib_device *dev, struct >>>> hmm_dma_map *map, >>>> +                   size_t nr_entries, size_t dma_entry_size) >>>> +{ >>>> +    if (ib_uses_virt_dma(dev)) >>>> +        return ib_dma_virt_map_alloc(dev->dma_device, map, nr_entries, >>>> +                         dma_entry_size); >>> >>> Other emulated RDMA devices driver also call ib_dma_virt_map_alloc? >>> Only rxe will call ib_dma_virt_map_alloc? > > Only rxe will call ib_dma_virt_map_alloc() > because currently only mlx5 and rxe will use ib_dma_map_alloc(). > >> >> As I know, other emulated RDMA driver also implemented ODP, and with >> the current hmm_dma_map_alloc, it can work well. >> So in the above "if (ib_uses_virt_dma(dev))", changed to if (rxe_dev), >> then go to call ib_dma_virt_map_alloc. > > Only mlx5 and rxe support ODP. While hmm_dma_map_alloc() works fine for > mlx5, No. Other private emulated RDMA driver also supports ODP, but it is not in the directory drivers/infiniband/sw/. It also call ib_dma_map_alloc and works well with hmm_dma_map_alloc. Up to you because the driver is not in kernel. I do not have strong preference. > it cannot be used for any drivers under drivers/infiniband/sw/ because > they all set > dma_device to NULL in ib_register_device(). > > So changing the condition to if (rxe_dev) makes the code too specific. > To my understanding, it's generally discouraged to add code in the RDMA > core > that targets a specific implementation. > > I have just realized that we can remove an argument "struct device" > from ib_dma_virt_map_alloc(). I will post the v2 to fix this. Please go ahead. Zhu Yanjun > > Thanks, > Daisuke > >> >> Yanjun.Zhu >> >>> >>> Zhu Yanjun >>> >>>> +    return hmm_dma_map_alloc(dev->dma_device, map, nr_entries, >>>> dma_entry_size); >>>> +} >>>> + >>>>   /** >>>>    * ib_dma_map_sgtable_attrs - Map a scatter/gather table to DMA >>>> addresses >>>>    * @dev: The device for which the DMA addresses are to be created >>> >> >