Hello Lu,
Hope you are doing well. I am Chaitanya from the linux graphics team in Intel.
This mail is regarding a regression we are seeing in our CI runs[1] on drm-tip repository.
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<4>[ 2.856622] WARNING: possible circular locking dependency detected
<4>[ 2.856631] 6.14.0-rc5-CI_DRM_16217-gc55ef90b69d3+ #1 Tainted: G I
<4>[ 2.856642] ------------------------------------------------------
<4>[ 2.856650] swapper/0/1 is trying to acquire lock:
<4>[ 2.856657] ffffffff8360ecc8 (iommu_probe_device_lock){+.+.}-{3:3}, at: iommu_probe_device+0x1d/0x70
<4>[ 2.856679]
but task is already holding lock:
<4>[ 2.856686] ffff888102ab6fa8 (&device->physical_node_lock){+.+.}-{3:3}, at: intel_iommu_init+0xea1/0x1220
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Details log can be found in [2].
After bisecting the tree, the following patch [3] seems to be the first "bad" commit
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commit b150654f74bf0df8e6a7936d5ec51400d9ec06d8
Author: Lu Baolu mailto:baolu.lu@xxxxxxxxxxxxxxx
Date: Fri Feb 28 18:27:26 2025 +0800
iommu/vt-d: Fix suspicious RCU usage
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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?
Gitlab issue for the regression is [4].
Thank you.
Regards
Chaitanya
[1] https://intel-gfx-ci.01.org/tree/drm-tip/combined-alt.html?
[2] https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_16276/fi-kbl-8809g/boot0.txt
[3] https://cgit.freedesktop.org/drm-tip/commit/?id=b150654f74bf0df8e6a7936d5ec51400d9ec06d8
[4] https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13818
Regards
Chaitanya
