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Date:   Fri, 16 Jun 2023 10:47:15 +0200
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Message-ID: <20230616084715.2140984-1-glider@google.com>
Subject: Re: [GIT PULL] x86/mm for 6.4
From:   Alexander Potapenko <glider@google.com>
To:     torvalds@linux-foundation.org
Cc:     dave.hansen@linux.intel.com, kirill.shutemov@linux.intel.com,
        linux-kernel@vger.kernel.org, peterz@infradead.org, x86@kernel.org,
        Alexander Potapenko <glider@google.com>
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Hi Linus,

>  static bool ex_handler_uaccess(const struct exception_table_entry *fixup,
> -			       struct pt_regs *regs, int trapnr)
> +			       struct pt_regs *regs, int trapnr,
> +			       unsigned long fault_address)
>  {
> -	WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?");
> +	WARN_ONCE(trapnr == X86_TRAP_GP && !gp_fault_address_ok(fault_address),
> +		"General protection fault in user access. Non-canonical address?");
>  	return ex_handler_default(fixup, regs);
>  }

Shouldn't ex_handler_copy() be fixed in the same way?
Looks like it's still possible for a tagged userspace address to be passed to it and trigger a warning.

Alex