Regression on linux-next (next-20250120)

Thu Jan 23 15:41:08 UTC 2025

Hello Al,

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-20250120 [2], we are seeing the following regression

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<4>[   21.520314] Oops: Oops: 0010 [#1] PREEMPT SMP NOPTI
<4>[   21.520317] CPU: 11 UID: 0 PID: 1384 Comm: debugfs_test Not tainted 6.13.0-next-20250121-next-20250121-gf066b5a6c7a0+ #1
<4>[   21.520319] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023
<4>[   21.520320] RIP: 0010:0x0
<4>[   21.520324] Code: Unable to access opcode bytes at 0xffffffffffffffd6.
<4>[   21.520325] RSP: 0018:ffffc90001f77b58 EFLAGS: 00010282
<4>[   21.520327] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90001f77c48
<4>[   21.520328] RDX: 0000000000000200 RSI: 00007fff2141fe40 RDI: ffff88810e38d440
<4>[   21.520329] RBP: ffffc90001f77b98 R08: 0000000000000000 R09: 0000000000000000
<4>[   21.520331] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881497ba648
<4>[   21.520332] R13: ffff88810e38d440 R14: ffff88812fd5f400 R15: ffffc90001f77c48
<4>[   21.520333] FS:  00007e64c0ee8900(0000) GS:ffff88885f180000(0000) knlGS:0000000000000000
<4>[   21.520334] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[   21.520336] CR2: ffffffffffffffd6 CR3: 0000000120674000 CR4: 0000000000f52ef0
<4>[   21.520337] PKRU: 55555554
<4>[   21.520338] Call Trace:
<4>[   21.520339]  <TASK>
<4>[   21.520341]  ? show_regs+0x6c/0x80
<4>[   21.520345]  ? __die+0x24/0x80
<4>[   21.520347]  ? page_fault_oops+0x175/0x5d0
<4>[   21.520351]  ? do_user_addr_fault+0x4c6/0x9d0
<4>[   21.520354]  ? exc_page_fault+0x8a/0x300
<4>[   21.520357]  ? asm_exc_page_fault+0x27/0x30
<4>[   21.520362]  full_proxy_read+0x6b/0xb0
<4>[   21.520366]  vfs_read+0xf9/0x390
.
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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 41a0ecc0997cd40d913cce18867efd1c34c64e28
Author: Al Viro mailto:viro at zeniv.linux.org.uk
Date:   Sun Jan 12 08:06:47 2025 +0000

    debugfs: get rid of dynamically allocation proxy_ops
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We could not revert the patch but resetting to the parent of the commit seems to fix the issue

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-20250120
[3] https://intel-gfx-ci.01.org/tree/linux-next/next-20250120/bat-rpls-4/dmesg0.txt 
[4] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20250120&id=41a0ecc0997cd40d913cce18867efd1c34c64e28