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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-17 23:10:50 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-17 23:10:50 +0300 |
commit | 90280eaa88ac1a9140dc759941123530d5545bb6 (patch) | |
tree | 82522018ded0269fba851ebc2cdfca7c07c0ed7b /Documentation/admin-guide | |
parent | 5d286d5ebcf6cb93b340f2439fe16a90b544c6e5 (diff) | |
parent | d98dbbe0d331b1a6dc1ca0b948c99d58cdba580c (diff) | |
download | linux-90280eaa88ac1a9140dc759941123530d5545bb6.tar.xz |
Merge tag 'docs-fixes' of git://git.lwn.net/linux
Pull documentation fixes from Jonathan Corbet:
"A handful of fixes for reasonably obnoxious documentation issues"
* tag 'docs-fixes' of git://git.lwn.net/linux:
scripts: documentation-file-ref-check: Add line break before exit
scripts/kernel-doc: Add missing close-paren in c:function directives
docs: admin-guide: merge sections for the kernel.modprobe sysctl
docs: timekeeping: Use correct prototype for deprecated functions
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 47 |
1 files changed, 19 insertions, 28 deletions
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 39c95c0e13d3..0d427fd10941 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -390,9 +390,17 @@ When ``kptr_restrict`` is set to 2, kernel pointers printed using modprobe ======== -This gives the full path of the modprobe command which the kernel will -use to load modules. This can be used to debug module loading -requests:: +The full 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. + +This sysctl can be used to debug module loading requests:: echo '#! /bin/sh' > /tmp/modprobe echo 'echo "$@" >> /tmp/modprobe.log' >> /tmp/modprobe @@ -400,10 +408,15 @@ requests:: chmod a+x /tmp/modprobe echo /tmp/modprobe > /proc/sys/kernel/modprobe -This only applies when the *kernel* is requesting that the module be -loaded; it won't have any effect if the module is being loaded -explicitly using ``modprobe`` from userspace. +Alternatively, 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. modules_disabled ================ @@ -446,28 +459,6 @@ 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 ============ |