Regression on linux-next (next-20241122)

[Borah, Chaitanya Kumar]

Hello Christoph,

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 linux-next repository.

Since the version next-20241122[2], we are seeing the following regression

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<4>[    5.177548] WARNING: CPU: 0 PID: 11 at mm/page_alloc.c:4763 __alloc_pages_noprof+0x1425/0x1470
<4>[    5.177560] Modules linked in:
<4>[    5.177564] CPU: 0 UID: 0 PID: 11 Comm: kworker/u80:0 Not tainted 6.12.0-next-20241122-next-20241122-gcfba9f07a1d6+ #1
<4>[    5.177574] Hardware name: Intel Corporation Raptor Lake Client Platform/RPL-S ADP-S DDR5 UDIMM CRB, BIOS RPLSFWI1.R00.4221.A00.2305271351 05/27/2023
<4>[    5.177584] Workqueue: async async_run_entry_fn
<4>[    5.177591] RIP: 0010:__alloc_pages_noprof+0x1425/0x1470
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Details log can be found in [3].

After bisecting the tree, the following patch [4] seems to be the first "bad"
commit

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commit 63a5c7a4b4c49ad86c362e9f555e6f343804ee1d
Author: Christoph Hellwig mailto:hch at lst.de
Date:   Fri Nov 1 05:40:05 2024 +0100

    nvme-pci: use dma_alloc_noncontigous if possible

    Use dma_alloc_noncontigous to allocate a single IOVA-contigous segment
    when backed by an IOMMU.  This allow to easily use bigger segments and
    avoids running into segment limits if we can avoid it.
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We also verified that if we revert the patch the issue is not seen.

This is now seen in our drm-tip runs as well. [5]

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/linux-next/combined-alt.html?
[2] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20241122
[3] https://intel-gfx-ci.01.org/tree/linux-next/next-20241128/bat-dg2-13/boot0.txt 
[4] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20241122&id=63a5c7a4b4c49ad86c362e9f555e6f343804ee1d
[5] https://intel-gfx-ci.01.org/tree/drm-tip/index.html?