linux-kernel - Re: [REGRESSION] module BTF validation failure (Error -22) on next

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Message-Id: <20241204155305.444280-1-laura.nao@collabora.com>
Date: Wed,  4 Dec 2024 16:53:05 +0100
From: Laura Nao <laura.nao@...labora.com>
To: ubizjak@...il.com
Cc: laura.nao@...labora.com,
	alan.maguire@...cle.com,
	bpf@...r.kernel.org,
	chrome-platform@...ts.linux.dev,
	kernel@...labora.com,
	linux-kernel@...r.kernel.org,
	regressions@...ts.linux.dev
Subject: Re: [REGRESSION] module BTF validation failure (Error -22) on next

On 11/15/24 18:17, Laura Nao wrote:
> I managed to reproduce the issue locally and I've uploaded the vmlinux[1]
> (stripped of DWARF data) and vmlinux.raw[2] files, as well as one of the
> modules[3] and its btf data[4] extracted with:
> 
> bpftool -B vmlinux btf dump file cros_kbd_led_backlight.ko > cros_kbd_led_backlight.ko.raw
> 
> Looking again at the logs[5], I've noticed the following is reported:
> 
> [    0.415885] BPF: 	 type_id=115803 offset=177920 size=1152
> [    0.416029] BPF:
> [    0.416083] BPF: Invalid offset
> [    0.416165] BPF:
> 
> There are two different definitions of rcu_data in '.data..percpu', one
> is a struct and the other is an integer:
> 
> type_id=115801 offset=177920 size=1152 (VAR 'rcu_data')
> type_id=115803 offset=177920 size=1152 (VAR 'rcu_data')
> 
> [115801] VAR 'rcu_data' type_id=115572, linkage=static
> [115803] VAR 'rcu_data' type_id=1, linkage=static
> 
> [115572] STRUCT 'rcu_data' size=1152 vlen=69
> [1] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
> 
> I assume that's not expected, correct?
> 
> I'll dig a bit deeper and report back if I can find anything else.

I ran a bisection, and it appears the culprit commit is:
https://lore.kernel.org/all/20241021080856.48746-2-ubizjak@gmail.com/

Hi Uros, do you have any suggestions or insights on resolving this issue?

This problem is now impacting mainline as well. The full context can be 
found at the beginning of this thread[1].

Thanks,

Laura

[1] https://lore.kernel.org/all/20241106160820.259829-1-laura.nao@collabora.com/

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