Message-Id: <DBKCYCNRNTMZ.1XJU81M6EE2D0@cknow.org>
Date: Thu, 24 Jul 2025 16:33:57 +0200
From: "Diederik de Haas" <didi.debian@...ow.org>
To: "Adrian Hunter" <adrian.hunter@...el.com>, "Robin Murphy"
 <robin.murphy@....com>, "Chen Wang" <unicornxw@...il.com>,
 <aou@...s.berkeley.edu>, <conor+dt@...nel.org>, <guoren@...nel.org>,
 <inochiama@...look.com>, <jszhang@...nel.org>,
 <krzysztof.kozlowski+dt@...aro.org>, <palmer@...belt.com>,
 <paul.walmsley@...ive.com>, <robh@...nel.org>, <ulf.hansson@...aro.org>,
 <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
 <linux-mmc@...r.kernel.org>, <linux-riscv@...ts.infradead.org>,
 <chao.wei@...hgo.com>, <haijiao.liu@...hgo.com>,
 <xiaoguang.xing@...hgo.com>, <tingzhu.wang@...hgo.com>
Cc: "Chen Wang" <unicorn_wang@...look.com>, "Drew Fustini" <drew@...7.com>,
 <linux-rockchip@...ts.infradead.org>
Subject: Re: [PATCH v6 1/8] mmc: sdhci-of-dwcmshc: add common bulk optional
 clocks support

Hi Adrian,

On Wed Jul 23, 2025 at 7:33 AM CEST, Adrian Hunter wrote:
> On 22/07/2025 21:33, Robin Murphy wrote:
>> A bit late for a "review", but Diederik and I have just been
>> IRC-debugging a crash on RK3568 which by inspection seems to be caused
>> by this patch:
>> 
>> On 2024-08-05 10:17 am, Chen Wang wrote:
>>> From: Chen Wang <unicorn_wang@...look.com>
>>>
>>> In addition to the required core clock and optional
>>> bus clock, the soc will expand its own clocks, so
>>> the bulk clock mechanism is abstracted.
>>>
>>> Note, I call the bulk clocks as "other clocks" due
>>> to the bus clock has been called as "optional".
>>>
>>> Signed-off-by: Chen Wang <unicorn_wang@...look.com>
>>> Tested-by: Drew Fustini <drew@...7.com> # TH1520
>>> Tested-by: Inochi Amaoto <inochiama@...look.com> # Duo and Huashan Pi
>>> ---
>> [...]
>>> +static int dwcmshc_get_enable_other_clks(struct device *dev,
>>> +                     struct dwcmshc_priv *priv,
>>> +                     int num_clks,
>>> +                     const char * const clk_ids[])
>>> +{
>>> +    int err;
>>> +
>>> +    if (num_clks > DWCMSHC_MAX_OTHER_CLKS)
>>> +        return -EINVAL;
>>> +
>>> +    for (int i = 0; i < num_clks; i++)
>>> +        priv->other_clks[i].id = clk_ids[i];
>>> +
>>> +    err = devm_clk_bulk_get_optional(dev, num_clks, priv->other_clks);
>> 
>> This leaves a pointer into "priv" in the devres list...
>> 
>>> +    if (err) {
>>> +        dev_err(dev, "failed to get clocks %d\n", err);
>>> +        return err;
>>> +    }
>>> +
>>> +    err = clk_bulk_prepare_enable(num_clks, priv->other_clks);
>>> +    if (err)
>>> +        dev_err(dev, "failed to enable clocks %d\n", err);
>>> +
>>> +    priv->num_other_clks = num_clks;
>>> +
>>> +    return err;
>>> +}
>>> +
>>>   /*
>>>    * If DMA addr spans 128MB boundary, we split the DMA transfer into two
>>>    * so that each DMA transfer doesn't exceed the boundary.
>> [...]
>>> @@ -1280,9 +1300,7 @@ static int dwcmshc_probe(struct platform_device *pdev)
>>>   err_clk:
>>>       clk_disable_unprepare(pltfm_host->clk);
>>>       clk_disable_unprepare(priv->bus_clk);
>>> -    if (rk_priv)
>>> -        clk_bulk_disable_unprepare(RK35xx_MAX_CLKS,
>>> -                       rk_priv->rockchip_clks);
>>> +    clk_bulk_disable_unprepare(priv->num_other_clks, priv->other_clks);
>>>   free_pltfm:
>>>       sdhci_pltfm_free(pdev);
>> 
>> ...but upon, say, -EPROBE_DEFER from sdhci_setup_host() because a
>> regulator isn't ready yet, that "priv" is freed here, so by the time the
>> devres callbacks eventually run, that "devres->clks" pointer which used
>> to represent "priv->other_clocks" points to who knows what, and this
>> sort of thing happens:
>> 
>> [   12.470827] Unable to handle kernel paging request at virtual address 002df7b378917664
>> [   12.472104] Mem abort info:
>> [   12.472471]   ESR = 0x0000000096000004
>> [   12.475991]   EC = 0x25: DABT (current EL), IL = 32 bits
>> [   12.476657]   SET = 0, FnV = 0
>> [   12.477146]   EA = 0, S1PTW = 0
>> [   12.477547]   FSC = 0x04: level 0 translation fault
>> [   12.478127] Data abort info:
>> [   12.478126] rockchip-gpio fdd60000.gpio: probed /pinctrl/gpio@...60000
>> [   12.478413]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
>> [   12.479826]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
>> [   12.480418]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
>> [   12.481282] [002df7b378917664] address between user and kernel address ranges
>> [   12.482421] Internal error: Oops: 0000000096000004 [#1]  SMP
>> [   12.482980] Modules linked in: sdhci_of_dwcmshc drm_dp_aux_bus gpio_rockchip(+) drm_display_helper dw_mmc_rockchip drm_client_lib sdhci_pltfm drm_dma_helper fwnode_mdio sdhci dw_mmc_pltf
>> m libphy fixed rockchip_dfi drm_kms_helper cqhci pl330(+) phy_rockchip_naneng_combphy dw_wdt phy_rockchip_snps_pcie3 phy_rockchip_inno_usb2 dw_mmc mdio_bus dwc3 ehci_platform ohci_platform
>> ehci_hcd drm ohci_hcd udc_core io_domain i2c_rk3x usbcore ulpi usb_common
>> [   12.486871] CPU: 0 UID: 0 PID: 64 Comm: kworker/u16:3 Not tainted 6.16-rc7-arm64-cknow #1 PREEMPTLAZY  Debian 6.16~rc7-1
>> [   12.487901] Hardware name: FriendlyElec NanoPi R5S (DT)
>> [   12.488412] Workqueue: async async_run_entry_fn
>> [   12.488879] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>> [   12.489539] pc : __clk_put+0x2c/0x138
>> [   12.489913] lr : __clk_put+0x2c/0x138
>> [   12.490281] sp : ffff800080713b10
>> [   12.490607] x29: ffff800080713b10 x28: ffff0001f001a120 x27: 0000000000000000
>> [   12.491302] x26: ffff0001f98e01a0 x25: 0000000000000000 x24: ffff0001f0f35408
>> [   12.491995] x23: ffffa8da199b4b40 x22: ffff800080713bb0 x21: ffff0001f0f35010
>> [   12.492689] x20: ffff0001f94aafd0 x19: 0a2df7b378917634 x18: 00000000ffffffff
>> [   12.493381] x17: 3d4d455453595342 x16: 555300307075656b x15: ffff0001f4885650
>> [   12.494075] x14: 0000000000000000 x13: ffff0001f025b810 x12: 0000000000008000
>> [   12.494765] x11: ffffa8da1a73ef98 x10: ffffa8da1a460000 x9 : 0000000000000078
>> [   12.495454] x8 : 0000000000000049 x7 : ffffa8da18c2fbe0 x6 : 0000000000000001
>> [   12.496145] x5 : 0000000000000004 x4 : 000000006cb6bb63 x3 : 0000000000000000
>> [   12.496833] x2 : 0000000000000000 x1 : ffff0001f1365ac0 x0 : 0000000000000001
>> [   12.497524] Call trace:
>> [   12.497776]  __clk_put+0x2c/0x138 (P)
>> [   12.498154]  clk_put+0x18/0x30
>> [   12.498471]  clk_bulk_put+0x40/0x68
>> [   12.498825]  devm_clk_bulk_release+0x24/0x40
>> [   12.499248]  release_nodes+0x64/0xa0
>> [   12.499608]  devres_release_all+0x98/0xf8
>> [   12.500004]  device_unbind_cleanup+0x20/0x70
>> [   12.500426]  really_probe+0x1e8/0x3a0
>> [   12.500793]  __driver_probe_device+0x84/0x160
>> [   12.501225]  driver_probe_device+0x44/0x128
>> [   12.501640]  __driver_attach_async_helper+0x5c/0x108
>> [   12.502125]  async_run_entry_fn+0x40/0x180
>> [   12.502535]  process_one_work+0x23c/0x640
>> [   12.502939]  worker_thread+0x1b4/0x360
>> [   12.503315]  kthread+0x150/0x250
>> [   12.503646]  ret_from_fork+0x10/0x20
>> [   12.504015] Code: aa0003f3 b140041f 540006c8 97ffd9c4 (b9403260)
>> [   12.504598] ---[ end trace 0000000000000000 ]---
>> 
>> 
>> TBH I'm not sure what to do as a straight revert seems impractical by
>> now, so we hope someone else might have a good idea.
>
> Presumably the problem has gone away with:
>
> 	commit 91a001a1a0749e5d24606d46ac5dfd4433c00956
> 	Author: Binbin Zhou <zhoubinbin@...ngson.cn>
> 	Date:   Sat Jun 7 15:39:01 2025 +0800
>
> 	    mmc: sdhci-of-dwcmshc: Drop the use of sdhci_pltfm_free()
>
> which is in next.
>
> In which case a separate fix is needed for stable.

Adding that patch to my 6.16-rc7 kernel indeed stopped the OOPSies.
Thanks!

Cheers,
  Diederik

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