Hi all, On 21.02.20 08:39, Greg Kroah-Hartman wrote: > From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> > > [ Upstream commit 02939cd167095f16328a1bd5cab5a90b550606df ] > > The current descriptor is not on any list of the virtual DMA channel. > Once sdma_terminate_all() is called when a descriptor is currently > in flight then this one is forgotten to be freed. We have to call > vchan_terminate_vdesc() on this descriptor to re-add it to the lists. > Now that we also free the currently running descriptor we can (and > actually have to) remove the current descriptor from its list also > for the cyclic case. > > Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> > Reviewed-by: Robin Gong <yibin.gong@xxxxxxx> > Tested-by: Robin Gong <yibin.gong@xxxxxxx> > Link: https://lore.kernel.org/r/20191216105328.15198-10-s.hauer@xxxxxxxxxxxxxx > Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > drivers/dma/imx-sdma.c | 19 +++++++++++-------- > 1 file changed, 11 insertions(+), 8 deletions(-) > > diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c > index c27e206a764c3..66f1b2ac5cde4 100644 > --- a/drivers/dma/imx-sdma.c > +++ b/drivers/dma/imx-sdma.c > @@ -760,12 +760,8 @@ static void sdma_start_desc(struct sdma_channel *sdmac) > return; > } > sdmac->desc = desc = to_sdma_desc(&vd->tx); > - /* > - * Do not delete the node in desc_issued list in cyclic mode, otherwise > - * the desc allocated will never be freed in vchan_dma_desc_free_list > - */ > - if (!(sdmac->flags & IMX_DMA_SG_LOOP)) > - list_del(&vd->node); > + > + list_del(&vd->node); > > sdma->channel_control[channel].base_bd_ptr = desc->bd_phys; > sdma->channel_control[channel].current_bd_ptr = desc->bd_phys; > @@ -1071,7 +1067,6 @@ static void sdma_channel_terminate_work(struct work_struct *work) > > spin_lock_irqsave(&sdmac->vc.lock, flags); > vchan_get_all_descriptors(&sdmac->vc, &head); > - sdmac->desc = NULL; > spin_unlock_irqrestore(&sdmac->vc.lock, flags); > vchan_dma_desc_free_list(&sdmac->vc, &head); > sdmac->context_loaded = false; > @@ -1080,11 +1075,19 @@ static void sdma_channel_terminate_work(struct work_struct *work) > static int sdma_disable_channel_async(struct dma_chan *chan) > { > struct sdma_channel *sdmac = to_sdma_chan(chan); > + unsigned long flags; > + > + spin_lock_irqsave(&sdmac->vc.lock, flags); > > sdma_disable_channel(chan); > > - if (sdmac->desc) > + if (sdmac->desc) { > + vchan_terminate_vdesc(&sdmac->desc->vd); > + sdmac->desc = NULL; > schedule_work(&sdmac->terminate_worker); > + } > + > + spin_unlock_irqrestore(&sdmac->vc.lock, flags); > > return 0; > } > This patch breaks our imx6 board with the attached trace. Reverting the patch makes it boot again. I tried also 5.6-rc3 and it booted too. A closer look into imx-sdma.c from 5.6-rc3 showed me some details which might have to be backported as well to make this patch work. I tried a1ff6a07f5a3951fcac84f064a76d1ad79c10e40 and was somehow successful. I still have one trace but the board boots now. Any insights from the experts? TIA, Andreas
klog: ------------[ cut here ]------------ klog: WARNING: CPU: 0 PID: 307 at kernel/dma/mapping.c:335 dma_free_attrs+0xc4/0xc8 klog: Modules linked in: nf_defrag_ipv4 klog: CPU: 0 PID: 307 Comm: gina Not tainted 5.4.22 #4 klog: Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) klog: [<c0110328>] (unwind_backtrace) from [<c010b7ec>] (show_stack+0x10/0x14) klog: [<c010b7ec>] (show_stack) from [<c08dd7f8>] (dump_stack+0x90/0xa4) klog: [<c08dd7f8>] (dump_stack) from [<c012bea0>] (__warn+0xbc/0xd8) klog: [<c012bea0>] (__warn) from [<c012bf20>] (warn_slowpath_fmt+0x64/0xc4) klog: [<c012bf20>] (warn_slowpath_fmt) from [<c0181a68>] (dma_free_attrs+0xc4/0xc8) klog: [<c0181a68>] (dma_free_attrs) from [<c04631c8>] (sdma_free_bd+0x30/0x38) klog: [<c04631c8>] (sdma_free_bd) from [<c04631dc>] (sdma_desc_free+0xc/0x18) klog: [<c04631dc>] (sdma_desc_free) from [<c0464f70>] (sdma_channel_synchronize+0x48/0x88) klog: [<c0464f70>] (sdma_channel_synchronize) from [<c0495fac>] (imx_uart_shutdown+0x16c/0x2a8) klog: [<c0495fac>] (imx_uart_shutdown) from [<c04857b8>] (uart_port_shutdown+0x34/0x40) klog: [<c04857b8>] (uart_port_shutdown) from [<c0485814>] (uart_tty_port_shutdown+0x50/0xb8) klog: [<c0485814>] (uart_tty_port_shutdown) from [<c048144c>] (tty_port_shutdown+0x90/0x9c) klog: [<c048144c>] (tty_port_shutdown) from [<c0481c2c>] (tty_port_close+0x3c/0x74) klog: [<c0481c2c>] (tty_port_close) from [<c0478458>] (tty_release+0xf0/0x48c) klog: [<c0478458>] (tty_release) from [<c02425ec>] (__fput+0x88/0x218) klog: [<c02425ec>] (__fput) from [<c0147798>] (task_work_run+0xa4/0xc4) klog: [<c0147798>] (task_work_run) from [<c010b310>] (do_work_pending+0x550/0x55c) klog: [<c010b310>] (do_work_pending) from [<c010106c>] (slow_work_pending+0xc/0x20) klog: Exception stack(0xee723fb0 to 0xee723ff8) klog: 3fa0: 00000000 00005402 bea6ab64 00000000 klog: 3fc0: 00000000 b6f124d0 bea6aba4 00000006 0000000d 00000001 00084ff8 00000000 klog: 3fe0: 0004822c bea6ab88 00034780 b6d08c34 600b0010 00000006 klog: ---[ end trace 86fea4e74a267f57 ]---
