Re: [PATCH] x86/pm: Fix false positive kmemleak report in msr_build_context().

[Dave Hansen]

On 3/14/24 07:26, Anton Altaparmakov wrote:
>  /* image of the saved processor state */
>  struct saved_context {
> -	/*
> -	 * On x86_32, all segment registers except gs are saved at kernel
> -	 * entry in pt_regs.
> -	 */
> -	u16 gs;
>  	unsigned long cr0, cr2, cr3, cr4;
>  	u64 misc_enable;
>  	struct saved_msrs saved_msrs;
> @@ -27,6 +22,11 @@ struct saved_context {
>  	unsigned long tr;
>  	unsigned long safety;
>  	unsigned long return_address;
> +	/*
> +	 * On x86_32, all segment registers except gs are saved at kernel
> +	 * entry in pt_regs.
> +	 */
> +	u16 gs;
>  	bool misc_enable_saved;
>  } __attribute__((packed));

Isn't this just kinda poking at the symptoms?  This seems to be
basically the exact same bug as b0b592cf08, just with a different source
of unaligned structure members.

There's nothing to keep folks from reintroducing these kinds of issues
and evidently no way to detect when they happen without lengthy reproducers.