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SubjectRe: [PATCH] lockdep: Fix static memory detection even more
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On 9/3/23 14:11, Helge Deller wrote:
> * Guenter Roeck <linux@roeck-us.net>:
>> Hi,
>>
>> On Sat, Aug 12, 2023 at 05:48:52PM +0200, Helge Deller wrote:
>>> On the parisc architecture, lockdep reports for all static objects which
>>> are in the __initdata section (e.g. "setup_done" in devtmpfs,
>>> "kthreadd_done" in init/main.c) this warning:
>>>
>>> INFO: trying to register non-static key.
>>>
>>> The warning itself is wrong, because those objects are in the __initdata
>>> section, but the section itself is on parisc outside of range from
>>> _stext to _end, which is why the static_obj() functions returns a wrong
>>> answer.
>>>
>>> While fixing this issue, I noticed that the whole existing check can
>>> be simplified a lot.
>>> Instead of checking against the _stext and _end symbols (which include
>>> code areas too) just check for the .data and .bss segments (since we check a
>>> data object). This can be done with the existing is_kernel_core_data()
>>> macro.
>>>
>>> In addition objects in the __initdata section can be checked with
>>> init_section_contains().
>>>
>>> This partly reverts and simplifies commit bac59d18c701 ("x86/setup: Fix static
>>> memory detection").
>>>
>>> Tested on x86-64 and parisc.
>>>
>>> Signed-off-by: Helge Deller <deller@gmx.de>
>>> Fixes: bac59d18c701 ("x86/setup: Fix static memory detection")
>>
>> On loongarch, this patch results in the following backtrace.
>>
>> EFI stub: Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path
>> EFI stub: Exiting boot services
>> [ 0.000000] INFO: trying to register non-static key.
>> [ 0.000000] The code is fine but needs lockdep annotation, or maybe
>> [ 0.000000] you didn't initialize this object before use?
>> [ 0.000000] turning off the locking correctness validator.
>> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 6.5.0+ #1
>> [ 0.000000] Stack : 0000000000000000 0000000000000000 9000000000223d6c 9000000001df0000
>> [ 0.000000] 9000000001df39a0 9000000001df39a8 0000000000000000 0000000000000000
>> [ 0.000000] 9000000001df39a8 0000000000000001 0000000000000000 900000000154b910
>> [ 0.000000] fffffffffffffffe 9000000001df39a8 0000000000000000 0000000000000000
>> [ 0.000000] 0000000000000001 0000000000000003 0000000000000010 0000000000000030
>> [ 0.000000] 0000000000000063 0000000000000001 0000000000000000 0000000000000000
>> [ 0.000000] 0000000000000000 0000000000000000 9000000001c60650 9000000001e12000
>> [ 0.000000] 0000000000000000 9000000001560bc0 0000000000000000 9000000002ee6000
>> [ 0.000000] 0000000000000000 0000000000000000 9000000000223d84 0000000000000000
>> [ 0.000000] 00000000000000b0 0000000000000004 0000000000000000 0000000000000800
>> [ 0.000000] ...
>> [ 0.000000] Call Trace:
>> [ 0.000000] [<9000000000223d84>] show_stack+0x5c/0x180
>> [ 0.000000] [<900000000153e0b4>] dump_stack_lvl+0x88/0xd0
>> [ 0.000000] [<90000000002bc548>] register_lock_class+0x768/0x770
>> [ 0.000000] [<90000000002bc710>] __lock_acquire+0xb0/0x2a18
>> [ 0.000000] [<90000000002bba1c>] lock_acquire+0x11c/0x328
>> [ 0.000000] [<9000000000b34a60>] __debug_object_init+0x60/0x244
>> [ 0.000000] [<9000000000337f94>] init_cgroup_housekeeping+0xe8/0x144
>> [ 0.000000] [<900000000033e364>] init_cgroup_root+0x38/0xa0
>> [ 0.000000] [<90000000017801ac>] cgroup_init_early+0x44/0x16c
>> [ 0.000000] [<9000000001770758>] start_kernel+0x50/0x624
>> [ 0.000000] [<90000000015410b4>] kernel_entry+0xb4/0xc4
>>
>> Reverting it fixes the problem. Bisect log attached.
>>
>> This is also seen in v6.5.y and v6.4.y since the patch has been applied
>> to those branches.
>
> Does this happens with CONFIG_SMP=n ?
> If so, I think the untested patch below might fix the issue.
>

No, this is loongarch:defconfig with various debug options enabled.
That has CONFIG_SMP=y.

Guenter

> Helge
>
> ---
>
> [PATCH] loogarch: Keep PERCPU section in init section even for !CONFIG_SMP
>
> Signed-off-by: Helge Deller <deller@gmx.de>
>
> diff --git a/arch/loongarch/kernel/vmlinux.lds.S b/arch/loongarch/kernel/vmlinux.lds.S
> index b1686afcf876..32d61e931cdc 100644
> --- a/arch/loongarch/kernel/vmlinux.lds.S
> +++ b/arch/loongarch/kernel/vmlinux.lds.S
> @@ -99,9 +99,7 @@ SECTIONS
> EXIT_DATA
> }
>
> -#ifdef CONFIG_SMP
> PERCPU_SECTION(1 << CONFIG_L1_CACHE_SHIFT)
> -#endif
>
> .init.bss : {
> *(.init.bss)

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