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Howlett" , Lorenzo Stoakes Cc: Xuanye Liu , Vlastimil Babka , Jann Horn , Pedro Falcato , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm: simplify min_brk handling in brk() Date: Thu, 10 Jul 2025 10:58:58 +0800 Message-ID: <20250710025859.926355-1-liuqiye2025@163.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wDHv3Z5LG9oBnhWDw--.47287S4 X-Coremail-Antispam: 1Uf129KBjvdXoWrZw48uFy8Gr4ktryxAw15XFb_yoWfKrb_Wr WI9a1UK3W5ArZ8KwsFv3yqy34kC34DCw18trsFgw4avr4DXrWFgrZ5u3ykJr97ZFZ3Xr1D AFsxX34xJw129jkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUvcSsGvfC2KfnxnUUI43ZEXa7IUUxsgUUUUUU== X-Originating-IP: [223.70.160.239] X-CM-SenderInfo: 5olx1xd1hsijqv6rljoofrz/1tbiMA6GUGhvKvMspAAAs+ X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 9F300C0002 X-Stat-Signature: 3ginjy9zdiqsgomajdaagspbed68s7wb X-HE-Tag: 1752116362-842564 X-HE-Meta: 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 0ZpRHglY 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 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: Set min_brk to mm->start_brk by default, and override it with mm->end_data only when CONFIG_COMPAT_BRK is enabled and brk_randomized is false. This makes the logic clearer with no functional change. Signed-off-by: Xuanye Liu --- mm/mmap.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index d8fa373e4ac1..7306253cc3b5 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -127,18 +127,15 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) origbrk = mm->brk; + min_brk = mm->start_brk; #ifdef CONFIG_COMPAT_BRK /* * CONFIG_COMPAT_BRK can still be overridden by setting * randomize_va_space to 2, which will still cause mm->start_brk * to be arbitrarily shifted */ - if (current->brk_randomized) - min_brk = mm->start_brk; - else + if (!current->brk_randomized) min_brk = mm->end_data; -#else - min_brk = mm->start_brk; #endif if (brk < min_brk) goto out; -- 2.43.0