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h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=FbU42jReibYsWd6NKeLPLPky/aF1mB/E/5caW6uLbtydQSXInHIvalDj+UTrucmln IVac9HVMny8XP6YKuQG1qxX4EIUfT4ejmLXHbaPXPbN+XCqX2KeCsSs/4yxZDqGWlA F3yTplVvLLv/4Zfv7lahY9A4k269KL0yro8NgtDo= Message-ID: Date: Tue, 28 Apr 2026 16:33:14 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 05/15] arm64: mm: Remove bogus stop condition from map_mem() loop To: Ard Biesheuvel , linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, Ard Biesheuvel , Ryan Roberts , Anshuman Khandual , Liz Prucka , Seth Jenkins , Kees Cook , Mike Rapoport , David Hildenbrand , Andrew Morton , linux-mm@kvack.org, linux-hardening@vger.kernel.org References: <20260427153416.2103979-17-ardb+git@google.com> <20260427153416.2103979-22-ardb+git@google.com> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: <20260427153416.2103979-22-ardb+git@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: B7A5B4000E X-Rspam-User: X-Stat-Signature: ua3cw6ad8uim5igk3prnts3ojq6ign7e X-HE-Tag: 1777386801-49197 X-HE-Meta: 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 0JIQxVpt 6mj9fdwnvdxcFhr3spPvwgKZOPlYv/aoHYzBOoVIoFsuzgHSqBHfDUSMy0RK19So7SEVA/V19/bHYtcq3gjTSvkM93YimBOiOm1otJHQO5Wkrj5i0ZEswGyAZp4pZsF5kN0Hj3e10sS2g+h4pshb0DyojA/UfRnyddTLa1YQh/87EQ+O6z73+65+TXQkRg9/RF2YsGL2I2aTcjrelf+/aiLiZG7Zpw1qKZc316X05vwVYVXvxxJk6EDXB7IlhQNjtkh7MDOhFJDpdJsaJiY5Lv3DuIxGMac3hyXNr/2PqN585e8sw1sj3C4OO7TTsm3EHZWp19iN9HKVKHL5m0rvQmu45U2E5GauHWiKreJJvqF9xqayJZQDq1qiQm5EXPQdiF4JeR0sZGSYadElp2lNcbT2l67uQmFhaOMiFCndwjLH0eGBAJ05NmRUJDQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 27/04/2026 17:34, Ard Biesheuvel wrote: > From: Ard Biesheuvel > > The memblock API guarantees that start is not greater than or equal to > end, so there is no need to test it. And if it were, it is doubtful that > breaking out of the loop would be a reasonable course of action here > (rather than attempting to map the remaining regions) > > So let's drop this check. > > Reviewed-by: Ryan Roberts > Signed-off-by: Ard Biesheuvel Reviewed-by: Kevin Brodsky > --- > arch/arm64/mm/mmu.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 005844e521bd..bfbf3fe0d1be 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1177,8 +1177,6 @@ static void __init map_mem(pgd_t *pgdp) > > /* map all the memory banks */ > for_each_mem_range(i, &start, &end) { > - if (start >= end) > - break; > /* > * The linear map must allow allocation tags reading/writing > * if MTE is present. Otherwise, it has the same attributes as