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b=BxtcyWLNCEPHr7mUdEW0SOd47sCFuUXFpsIonfxcF4PTL0hXAtied1L9lyTfVPQLC oQuf+Wv7E3qwZWSdjorXHZZDP0pp/acJw8bCyvWzBHA6sQiOwPbyI6X6JCBn0Ym+b6 X1yLATfFGAtlsKUJggVIxr632ZvZE/wGiwQWAmoD8A7cvzVRINjkJLsbuQkOC/p95P LHPiOPlruVhOs5+WYEk6V7y1eGVZPNumqsGCZi8JwELyIT1rg8yw9l50kcx9FAAVjF 9/iOkxVpuwxm1y0uEBWrfJayokUcXjk85ZskmtGgfkZ42Uc7XeXe9VfQV5eJMTHpGB 111HYgIgvFnQQ== From: Pratyush Yadav To: Pasha Tatashin Cc: pratyush@kernel.org, rppt@kernel.org, dmatlack@google.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] liveupdate: luo_core: fix redundant bound check in luo_ioctl() In-Reply-To: <20251130010919.1488230-1-pasha.tatashin@soleen.com> (Pasha Tatashin's message of "Sat, 29 Nov 2025 20:09:19 -0500") References: <20251130010919.1488230-1-pasha.tatashin@soleen.com> Date: Sun, 30 Nov 2025 23:53:42 +0100 Message-ID: <86v7irm8sp.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: BFC7040004 X-Rspamd-Server: rspam06 X-Rspam-User: X-Stat-Signature: ezah15n5typu48xajspn4ydj7tbyyhtu X-HE-Tag: 1764543228-46322 X-HE-Meta: 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 mNi0QHR1 8u37xi2s3bncPhdGrlhRmHF3COwhVVqcIDbZpGWQQrw7yeLQIBEPw3WaBDfIsIYPI3+syjYEalgZ1+r9DJo76IE5l7QCnU7yQoCrBnKtQMoOSltOM8buy9SNoFVIXjIYTylG6wfRUbfZ4emyttjglDPBEXt3T0BLE+USrzIteh23ZJKpo+ql1B+Kz0ZVVYuWHsOZEUWu3g+noOWlbx/PDxEt6RSflIPAJq4dGiwA0RoY1H1LVGNq7yd8DsV7L6R+nauBHhhnO+4Rn3LJTH7+G9wkep0/ulscOLsJJqENXUDmUQp8LT7yfJigFoMDkfP+LXqnh X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, Nov 29 2025, Pasha Tatashin wrote: > The kernel test robot reported a Smatch warning: > kernel/liveupdate/luo_core.c:402 luo_ioctl() warn: unsigned 'nr' is > never less than zero. > > This occurs because 'nr' is unsigned and LIVEUPDATE_CMD_BASE is > currently defined as 0, making the check (nr < LIVEUPDATE_CMD_BASE) > always false. > > Remove the explicit lower bound check. The logic remains correct because > 'nr' is unsigned; if nr is less than LIVEUPDATE_CMD_BASE, the expression > (nr - LIVEUPDATE_CMD_BASE) will wrap around to a large positive value. > This will inevitably be larger than ARRAY_SIZE(luo_ioctl_ops) and be > caught by the upper bound check. > > Reported-by: kernel test robot > Closes: https://lore.kernel.org/oe-kbuild-all/202511280300.6pvBmXUS-lkp@intel.com/ > Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav [...] -- Regards, Pratyush Yadav