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[178.24.244.57]) by smtp.gmail.com with ESMTPSA id p140sm1813229wme.31.2019.06.26.11.15.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Jun 2019 11:15:05 -0700 (PDT) From: Eugeniu Rosca X-Google-Original-From: Eugeniu Rosca Date: Wed, 26 Jun 2019 20:14:59 +0200 To: Geert Uytterhoeven Cc: Vinod Koul , Dan Williams , Greg Kroah-Hartman , Jiri Slaby , Yoshihiro Shimoda , Wolfram Sang , linux-serial@vger.kernel.org, linux-renesas-soc@vger.kernel.org, dmaengine@vger.kernel.org, Eugeniu Rosca , Eugeniu Rosca Subject: Re: [PATCH] dmaengine: rcar-dmac: Reject zero-length slave DMA requests Message-ID: <20190626181459.GA31913@x230> References: <20190624123818.20919-1-geert+renesas@glider.be> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190624123818.20919-1-geert+renesas@glider.be> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org Hi All, On Mon, Jun 24, 2019 at 02:38:18PM +0200, Geert Uytterhoeven wrote: [..] > - if (rchan->mid_rid < 0 || !sg_len) { > + if (rchan->mid_rid < 0 || !sg_len || !sg_dma_len(sgl)) { > dev_warn(chan->device->dev, > "%s: bad parameter: len=%d, id=%d\n", > __func__, sg_len, rchan->mid_rid); Just wanted to share the WARN output proposed by Wolfram in https://patchwork.kernel.org/patch/11012991/#22721733 in case the issue discussed in [1] is reproduced with this patch: [ 2.065337] ------------[ cut here ]------------ [ 2.065346] rcar_dmac_prep_slave_sg: [ 2.065394] WARNING: CPU: 2 PID: 252 at drivers/dma/sh/rcar-dmac.c:1169 rcar_dmac_prep_slave_sg+0x50/0xc4 [ 2.065397] Modules linked in: [ 2.065407] CPU: 2 PID: 252 Comm: kworker/2:1 Not tainted 5.2.0-rc6-00016-g2bfb85ba1481-dirty #26 [ 2.065410] Hardware name: Renesas H3ULCB Kingfisher board based on r8a7795 ES2.0+ (DT) [ 2.065420] Workqueue: events sci_dma_tx_work_fn [ 2.065425] pstate: 40000005 (nZcv daif -PAN -UAO) [ 2.065430] pc : rcar_dmac_prep_slave_sg+0x50/0xc4 [ 2.065434] lr : rcar_dmac_prep_slave_sg+0x50/0xc4 [ 2.065436] sp : ffff0000112ebd00 [ 2.065438] x29: ffff0000112ebd00 x28: 0000000000000000 [ 2.065443] x27: ffff8006fa367138 x26: ffff000010c5bce8 [ 2.065447] x25: 0000000738b1d000 x24: 0000000000000000 [ 2.065451] x23: ffff000010b76e00 x22: ffff000010a18000 [ 2.065455] x21: 0000000000000001 x20: ffff8006f9b5a080 [ 2.065459] x19: ffff0000107adc86 x18: 0000000000000000 [ 2.065462] x17: 0000000000000000 x16: 0000000000000000 [ 2.065466] x15: 0000000000000000 x14: 0000000000000000 [ 2.065469] x13: 0000000000040000 x12: ffff000010a35000 [ 2.065473] x11: ffff000010b12981 x10: 0000000000000040 [ 2.065477] x9 : 000000000000013e x8 : ffff000010b1b73b [ 2.065481] x7 : 0000000000000000 x6 : 0000000000000001 [ 2.065484] x5 : ffff8006ff72f7c0 x4 : 0000000000000001 [ 2.065488] x3 : 0000000000000007 x2 : 0000000000000007 [ 2.065491] x1 : 878c73041cedc400 x0 : 0000000000000000 [ 2.065495] Call trace: [ 2.065500] rcar_dmac_prep_slave_sg+0x50/0xc4 [ 2.065504] sci_dma_tx_work_fn+0xd8/0x1d4 [ 2.065511] process_one_work+0x1dc/0x394 [ 2.065515] worker_thread+0x21c/0x308 [ 2.065520] kthread+0x118/0x128 [ 2.065527] ret_from_fork+0x10/0x18 [ 2.065530] ---[ end trace 75fc17d9000f1224 ]--- At first glance, it seems to give more details compared to: rcar-dmac e7300000.dma-controller: rcar_dmac_prep_slave_sg: bad parameter: len=1, id=19 [1] https://patchwork.kernel.org/cover/11012981/ -- Best regards, Eugeniu.