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| author | Eric Biggers <ebiggers@google.com> | 2020-04-10 23:33:50 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-11 00:36:22 +0200 |
| commit | 6e71582506258c9b2efd8f164706f2af2256cf16 (patch) | |
| tree | 195e8937c64176026b4974679f3385ea7d92f73a /Documentation | |
| parent | fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once() (diff) | |
| download | linux-6e71582506258c9b2efd8f164706f2af2256cf16.tar.xz linux-6e71582506258c9b2efd8f164706f2af2256cf16.zip | |
docs: admin-guide: document the kernel.modprobe sysctl
Document the kernel.modprobe sysctl in the same place that all the other
kernel.* sysctls are documented. Make sure to mention how to use this
sysctl to completely disable module autoloading, and how this sysctl
relates to CONFIG_STATIC_USERMODEHELPER.
[ebiggers@google.com: v5]
Link: http://lkml.kernel.org/r/20200318230515.171692-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: NeilBrown <neilb@suse.com>
Link: http://lkml.kernel.org/r/20200312202552.241885-4-ebiggers@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 335696d3360d..39c95c0e13d3 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -446,6 +446,27 @@ Notes: successful IPC object allocation. If an IPC object allocation syscall fails, it is undefined if the value remains unmodified or is reset to -1. +modprobe: +========= + +The path to the usermode helper for autoloading kernel modules, by +default "/sbin/modprobe". This binary is executed when the kernel +requests a module. For example, if userspace passes an unknown +filesystem type to mount(), then the kernel will automatically request +the corresponding filesystem module by executing this usermode helper. +This usermode helper should insert the needed module into the kernel. + +This sysctl only affects module autoloading. It has no effect on the +ability to explicitly insert modules. + +If this sysctl is set to the empty string, then module autoloading is +completely disabled. The kernel will not try to execute a usermode +helper at all, nor will it call the kernel_module_request LSM hook. + +If CONFIG_STATIC_USERMODEHELPER=y is set in the kernel configuration, +then the configured static usermode helper overrides this sysctl, +except that the empty string is still accepted to completely disable +module autoloading as described above. nmi_watchdog ============ |