Regression on linux-next (next-20241203)

[Borah, Chaitanya Kumar]

Hello Tamir,

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-20241203 [2], we are seeing the following regression

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<4>[   28.896758] WARNING: CPU: 10 PID: 1318 at drivers/gpu/drm/i915/gem/i915_gem_context.c:2469 i915_gem_context_destroy_ioctl+0xae/0xd0 [i915]
<4>[   28.896937] Modules linked in: snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_timer snd soundcore i915 prime_numbers ttm drm_display_helper cec rc_core drm_kms_helper drm_buddy i2c_algo_bit cdc_mbim cdc_wdm cdc_ncm cdc_ether usbnet intel_rapl_msr intel_rapl_common intel_uncore_frequency intel_uncore_frequency_common intel_tcc_cooling x86_pkg_temp_thermal intel_powerclamp hid_generic spd5118 coretemp cmdlinepart mei_pxp mei_hdcp spi_nor eeepc_wmi asus_nb_wmi mtd asus_wmi sparse_keymap platform_profile wmi_bmof kvm_intel kvm polyval_clmulni polyval_generic ghash_clmulni_intel sha256_ssse3 r8152 sha1_ssse3 usbhid mii aesni_intel hid crypto_simd cryptd r8169 rapl intel_cstate video realtek i2c_i801 spi_intel_pci mei_me i2c_mux i2c_smbus idma64 mei spi_intel nls_iso8859_1 intel_pmc_core intel_vsec pmt_telemetry acpi_tad pmt_class wmi pinctrl_alderlake acpi_pad dm_multipath msr nvme_fabrics fuse efi_pstore nfnetlink ip_tables x_tables
<4>[   28.896999] CPU: 10 UID: 0 PID: 1318 Comm: i915_module_loa Not tainted 6.13.0-rc1-next-20241203-next-20241203-gc245a7a79602+ #1
<4>[   28.897001] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023
<4>[   28.897002] RIP: 0010:i915_gem_context_destroy_ioctl+0xae/0xd0 [i915]

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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 d2e88c71bdb07f1e5ccffbcc80d747ccd6144b75
Author: Tamir Duberstein mailto:tamird at gmail.com
Date:   Tue Nov 12 14:25:37 2024 -0500

    xarray: extract helper from __xa_{insert,cmpxchg}
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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?

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-20241203 
[3] https://gfx-ci.igk.intel.com/tree/linux-next/next-20241203/bat-rpls-4/dmesg0.txt
[4] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20241203&id=d2e88c71bdb07f1e5ccffbcc80d747ccd6144b75