On 2024/8/27 9:56, Paul Moore wrote:

On Mon, Aug 26, 2024 at 9:38 PM yukaixiong [off-list ref] wrote:

quoted

On 2024/8/27 6:49, Paul Moore wrote:

quoted

On Mon, Aug 26, 2024 at 8:05 AM Kaixiong Yu [off-list ref] wrote:

quoted

The dac_mmap_min_addr belongs to min_addr.c, move it into
its own file from /kernel/sysctl.c. In the previous Linux kernel
boot process, sysctl_init_bases needs to be executed before
init_mmap_min_addr, So, register_sysctl_init should be executed
before update_mmap_min_addr in init_mmap_min_addr.

Signed-off-by: Kaixiong Yu <redacted>
---
   kernel/sysctl.c     |  9 ---------
   security/min_addr.c | 11 +++++++++++
   2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 41d4afc978e6..0c0bab3dad7d 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c

@@ -2059,15 +2059,6 @@ static struct ctl_table vm_table[] = {
                  .proc_handler   = proc_dointvec_minmax,
                  .extra1         = SYSCTL_ZERO,
          },
-#ifdef CONFIG_MMU
-       {
-               .procname       = "mmap_min_addr",
-               .data           = &dac_mmap_min_addr,
-               .maxlen         = sizeof(unsigned long),
-               .mode           = 0644,
-               .proc_handler   = mmap_min_addr_handler,
-       },
-#endif
   #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
      (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
          {

diff --git a/security/min_addr.c b/security/min_addr.c
index 0ce267c041ab..b2f61649e110 100644
--- a/security/min_addr.c
+++ b/security/min_addr.c

@@ -44,8 +44,19 @@ int mmap_min_addr_handler(const struct ctl_table *table, int write,
          return ret;
   }

+static struct ctl_table min_addr_sysctl_table[] = {
+       {
+               .procname       = "mmap_min_addr",
+               .data           = &dac_mmap_min_addr,
+               .maxlen         = sizeof(unsigned long),
+               .mode           = 0644,
+               .proc_handler   = mmap_min_addr_handler,
+       },
+};

I haven't chased all of the Kconfig deps to see if there is a problem,
but please provide a quick explanation in the commit description about
why it is okay to drop the CONFIG_MMU check.

According to the compilation condition in security/Makefile:

                obj-$(CONFIG_MMU)            += min_addr.o

if CONFIG_MMU is not defined, min_addr.c would not be included in the
compilation process.
So，it is okay to drop the CONFIG_MMU check.

Great, please add some text about that in the commit description as it
is an important difference in the code changes that isn't currently
documented in the patch.

ok, I will add the related text in this patch series v2.