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Date: Thu, 29 Feb 2024 15:55:10 +0100
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Naresh Kamboju" <naresh.kamboju@linaro.org>,
 linux-block <linux-block@vger.kernel.org>, lkft-triage@lists.linaro.org,
 "open list" <linux-kernel@vger.kernel.org>
Cc: "Jens Axboe" <axboe@kernel.dk>, "Christoph Hellwig" <hch@lst.de>,
 "Christian Brauner" <brauner@kernel.org>,
 "Ulf Hansson" <ulf.hansson@linaro.org>,
 "Dan Carpenter" <dan.carpenter@linaro.org>,
 "Anders Roxell" <anders.roxell@linaro.org>,
 "Ulf Hansson" <ulf.hansson@linaro.org>,
 "Jaehoon Chung" <jh80.chung@samsung.com>, linux-mmc@vger.kernel.org
Subject: Re: WinLink E850-96: WARNING: at block/blk-settings.c:204 blk_validate_limits
Content-Type: text/plain

On Thu, Feb 29, 2024, at 15:14, Naresh Kamboju wrote:
> The arm64 WinLink E850-96 Board boot failed with 16K and 64K page size builds
> Please find the below warning log on Linux next-20240229.
> First noticed on the next-20240220 tag.
>
> This issue arises only when one of these Kconfig options is enabled.
>   CONFIG_ARM64_16K_PAGES=y
>   CONFIG_ARM64_64K_PAGES=y
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>
> Warning log:
> -------
> [    2.231008] mmc_host mmc0: Bus speed (slot 0) = 49968750Hz (slot
> req 52000000Hz, actual 49968750HZ div = 0)
> [    2.231714] mmc_host mmc0: Bus speed (slot 0) = 399750000Hz (slot
> req 200000000Hz, actual 199875000HZ div = 1)
> [    2.241961] mmc0: new HS400 Enhanced strobe MMC card at address 0001
> [    2.249182] ------------[ cut here ]------------
> [    2.252371] WARNING: CPU: 3 PID: 90 at block/blk-settings.c:204
> blk_validate_limits (block/blk-settings.c:204 (discriminator 1))


The warning was added with commit d690cb8ae14b ("block: add
an API to atomically update queue limits")

+               if (!lim->max_segment_size)
+                       lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
+               if (WARN_ON_ONCE(lim->max_segment_size < PAGE_SIZE))
+                       return -EINVAL;

Whereas mmc_alloc_disk sets the limit as

        /*
         * Setting a virt_boundary implicity sets a max_segment_size, so try
         * to set the hardware one here.
         */
        if (host->can_dma_map_merge) {
                lim.virt_boundary_mask = dma_get_merge_boundary(mmc_dev(host));
                lim.max_segments = MMC_DMA_MAP_MERGE_SEGMENTS;
        } else {
                lim.max_segment_size =
                        round_down(host->max_seg_size, lim.logical_block_size);
                lim.max_segments = host->max_segs;
        }

and max_seg_size gets initialized to either one less
than 64k, or to exactly 4k in the dwmmc driver here:

        /* Useful defaults if platform data is unset. */
        if (host->use_dma == TRANS_MODE_IDMAC) {
                mmc->max_segs = host->ring_size;
                mmc->max_blk_size = 65535;
                mmc->max_seg_size = 0x1000;
                mmc->max_req_size = mmc->max_seg_size * host->ring_size;
                mmc->max_blk_count = mmc->max_req_size / 512;
        } else if (host->use_dma == TRANS_MODE_EDMAC) {
                mmc->max_segs = 64;
                mmc->max_blk_size = 65535;
                mmc->max_blk_count = 65535;
                mmc->max_req_size =
                                mmc->max_blk_size * mmc->max_blk_count;
                mmc->max_seg_size = mmc->max_req_size;
        } else {
                /* TRANS_MODE_PIO */
                mmc->max_segs = 64;
                mmc->max_blk_size = 65535; /* BLKSIZ is 16 bits */
                mmc->max_blk_count = 512;
                mmc->max_req_size = mmc->max_blk_size *
                                    mmc->max_blk_count;
                mmc->max_seg_size = mmc->max_req_size;
        }

Adding the mmc and dw-mmc maintainers to cc for clarification.

     Arnd

> [    2.261056] Modules linked in:
> [    2.264082] CPU: 3 PID: 90 Comm: kworker/3:1 Not tainted
> 6.8.0-rc6-next-20240229 #1
> [    2.271724] Hardware name: WinLink E850-96 board (DT)
> [    2.276756] Workqueue: events_freezable mmc_rescan
> [    2.281534] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [    2.288479] pc : blk_validate_limits (block/blk-settings.c:204
> (discriminator 1))
> [    2.293076] lr : blk_set_default_limits (block/blk-settings.c:241)
> <trim>
> [    2.337595] PM: genpd: Disabling unused power domains
> [    2.338361] xhci-hcd xhci-hcd.0.auto: remove, state 84
> [    2.338391] usb usb1: USB disconnect, device number 1
> [    2.343322]  x1 : 0000000000001000 x0 : ffff8000a504f888
> [    2.343335] Call trace:
> [    2.343339] blk_validate_limits (block/blk-settings.c:204 (discriminator 1))
> [    2.343350] blk_alloc_queue (block/blk-core.c:421)
> [    2.343362] blk_mq_alloc_queue (block/blk-mq.c:4083 (discriminator 4))
> [    2.350571] ALSA device list:
> [    2.352700] xhci-hcd xhci-hcd.0.auto: USB bus 1 deregistered
> [    2.355651] __blk_mq_alloc_disk (block/blk-mq.c:4130)
> [    2.355664] mmc_alloc_disk (drivers/mmc/core/queue.c:379)
> [    2.355678] mmc_init_queue (drivers/mmc/core/queue.c:463)
> [    2.359577]   No soundcards found.
> [    2.362942] mmc_blk_alloc_req (drivers/mmc/core/block.c:2500
> (discriminator 1))
> [    2.362951] mmc_blk_probe (drivers/mmc/core/block.c:2603
> drivers/mmc/core/block.c:3025)
> [    2.446877] mmc_bus_probe (drivers/mmc/core/bus.c:132)
> [    2.446892] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658)
> [    2.454016] __driver_probe_device (drivers/base/dd.c:800)
> [    2.458346] driver_probe_device (drivers/base/dd.c:830)
> [    2.462513] __device_attach_driver (drivers/base/dd.c:959)
> [    2.466939] bus_for_each_drv (drivers/base/bus.c:457)
> [    2.470761] __device_attach (drivers/base/dd.c:1032)
> [    2.474579] device_initial_probe (drivers/base/dd.c:1080)
> [    2.478746] bus_probe_device (drivers/base/bus.c:532)
> [    2.482563] device_add (drivers/base/core.c:3646)
> [    2.486037] mmc_add_card (drivers/mmc/core/bus.c:371)
> [    2.489683] mmc_attach_mmc (drivers/mmc/core/mmc.c:2353)
> [    2.493500] mmc_rescan (drivers/mmc/core/core.c:2097 (discriminator
> 1) drivers/mmc/core/core.c:2259 (discriminator 1))
> [    2.496974] process_one_work (kernel/workqueue.c:3253)
> [    2.500966] worker_thread (kernel/workqueue.c:3322 (discriminator
> 2) kernel/workqueue.c:3409 (discriminator 2))
> [    2.504700] kthread (kernel/kthread.c:388)
> [    2.507914] ret_from_fork (arch/arm64/kernel/entry.S:861)
> [    2.511473] ---[ end trace 0000000000000000 ]---
> [    2.516435] mmcblk: probe of mmc0:0001 failed with error -22
> [    2.522114] Waiting for root device /dev/mmcblk0p12...
>
> Kconfig:
>  - 
> https://storage.tuxsuite.com/public/linaro/lkft/builds/2ccVUNsQjaWBcREYI0wFRjzG3oa/config
>
> Steps to reproduce:
>  - 
> https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2ccVWjLtBJ3IuDSKLkyaFholQ67/reproducer
>
> Links:
>  - 
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240229/testrun/22884460/suite/boot/test/gcc-13-lkftconfig-16k_page_size/log
>  - 
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240229/testrun/22884435/suite/boot/test/gcc-13-lkftconfig-64k_page_size/details/
>  - 
> https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2d2JxLaSCZ6cTNGMeKdCbAjk9Sh
>  - 
> https://storage.tuxsuite.com/public/linaro/lkft/builds/2d2JuyeiEHCtWGJYV80n1tF77lh/
>
>
> --
> Linaro LKFT
> https://lkft.linaro.org