[REGRESSION] v6.15-rc3: 1a931c4f5e68 ("igc: add lock preventing multiple simultaneous PTM transactions")

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 28 Apr 2025, "Borah, Chaitanya Kumar" <chaitanya.kumar.borah@intel.com> wrote:
> Hello Christopher,
>
> This mail is regarding a regression we are seeing in our CI runs[1] on drm-tip[2] repository.

The regressing commit is in v6.15-rc3. Updated subject and Cc'd
regression tracking.

BR,
Jani.


>
> `````````````````````````````````````````````````````````````````````````````````
> <4>[    7.891028] =============================
> <4>[    7.891293] [ BUG: Invalid wait context ]
> <4>[    7.891526] 6.15.0-rc3-CI_DRM_16443-gdc80d6a10c1c+ #1 Tainted: G        W          
> <4>[    7.891792] -----------------------------
> <4>[    7.892070] (udev-worker)/286 is trying to lock:
> <4>[    7.892349] ffff88811671bcc8 (&adapter->ptm_lock){....}-{3:3}, at: igc_ptp_reset+0x155/0x320 [igc]
> <4>[    7.892660] other info that might help us debug this:
> <4>[    7.892943] context-{4:4}
> <4>[    7.893226] 2 locks held by (udev-worker)/286:
> <4>[    7.893515]  #0: ffff888103bd41b0 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x104/0x220
> <4>[    7.893823]  #1: ffff88811671bb70 (&adapter->tmreg_lock){....}-{2:2}, at: igc_ptp_reset+0x53/0x320 [igc]
> <4>[    7.894134] stack backtrace:
> <4>[    7.894439] CPU: 2 UID: 0 PID: 286 Comm: (udev-worker) Tainted: G        W           6.15.0-rc3-CI_DRM_16443-gdc80d6a10c1c+ #1 PREEMPT(voluntary) 
> <4>[    7.894442] Tainted: [W]=WARN
> <4>[    7.894443] Hardware name: Intel(R) Client Systems NUC11TNHi3/NUC11TNBi3, BIOS TNTGL357.0067.2022.0718.1742 07/18/2022
> `````````````````````````````````````````````````````````````````````````````````
> Detailed log can be found in [3].
>
> After bisecting the tree, the following patch [4] seems to be the first "bad"
> commit
>
> `````````````````````````````````````````````````````````````````````````````````````````````````````````
> commit 1a931c4f5e6862e61a4b130cb76b422e1415f644
> Author: Christopher S M Hall mailto:christopher.s.hall@intel.com
> Date:   Tue Apr 1 16:35:34 2025 -0700
>
>     igc: add lock preventing multiple simultaneous PTM transactions
> `````````````````````````````````````````````````````````````````````````````````````````````````````````
>
> We also verified that if we revert the patch the issue is not seen.
>
> Could you please check why the patch causes this regression and provide a fix if necessary?
>
> Thank you.
>
> Regards
>
> Chaitanya
>
> [1] https://intel-gfx-ci.01.org/tree/drm-tip/shard-tglu.html
> [2] https://cgit.freedesktop.org/drm-tip/tree/
> [3] https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_16443/fi-tgl-1115g4/boot0.txt
> [4] https://cgit.freedesktop.org/drm-tip/commit/?id=1a931c4f5e6862e61a4b130cb76b422e1415f644
>

-- 
Jani Nikula, Intel