All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, ast@kernel.org, ebiggers@google.com,
	gregkh@linuxfoundation.org, jeffv@google.com, jeyu@kernel.org,
	keescook@chromium.org, linux-mm@kvack.org, mcgrof@kernel.org,
	mm-commits@vger.kernel.org, neilb@suse.com,
	torvalds@linux-foundation.org
Subject: [patch 28/35] docs: admin-guide: document the kernel.modprobe sysctl
Date: Fri, 10 Apr 2020 14:33:50 -0700	[thread overview]
Message-ID: <20200410213350.o21mcrRmh%akpm@linux-foundation.org> (raw)
In-Reply-To: <20200410143047.bf34a933ce1affdc042c7c80@linux-foundation.org>

From: Eric Biggers <ebiggers@google.com>
Subject: 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
Link: http://lkml.kernel.org/r/20200312202552.241885-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/admin-guide/sysctl/kernel.rst |   21 ++++++++++++++++++
 1 file changed, 21 insertions(+)

--- a/Documentation/admin-guide/sysctl/kernel.rst~docs-admin-guide-document-the-kernelmodprobe-sysctl
+++ a/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
 ============
_

  parent reply	other threads:[~2020-04-10 21:33 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-10 21:30 incoming Andrew Morton
2020-04-10 21:32 ` [patch 01/35] hfsplus: fix crash and filesystem corruption when deleting files Andrew Morton
2020-04-10 21:32 ` [patch 02/35] mm, memcg: do not high throttle allocators based on wraparound Andrew Morton
2020-04-10 21:32 ` [patch 03/35] mm, slab_common: fix a typo in comment "eariler"->"earlier" Andrew Morton
2020-04-10 21:32 ` [patch 04/35] docs: mm: slab.h: fix a broken cross-reference Andrew Morton
2020-04-10 21:32 ` [patch 05/35] mm/page_alloc.c: fix kernel-doc warning Andrew Morton
2020-04-10 21:32 ` [patch 06/35] mm/page_alloc: make pcpu_drain_mutex and pcpu_drain static Andrew Morton
2020-04-10 21:32 ` [patch 07/35] mm/gup: fix null pointer dereference detected by coverity Andrew Morton
2020-04-10 22:24   ` Linus Torvalds
2020-04-10 23:53     ` Peter Xu
2020-04-11  0:19       ` Linus Torvalds
2020-04-14  4:04     ` Miles Chen
2020-04-10 21:32 ` [patch 08/35] ocfs2: no need try to truncate file beyond i_size Andrew Morton
2020-04-10 21:32 ` [patch 09/35] mm: cma: NUMA node interface Andrew Morton
2020-04-10 21:32 ` [patch 10/35] mm: hugetlb: optionally allocate gigantic hugepages using cma Andrew Morton
2020-04-10 21:32 ` [patch 11/35] mm/mmap.c: initialize align_offset explicitly for vm_unmapped_area Andrew Morton
2020-04-10 21:32 ` [patch 12/35] mm/memory.c: refactor insert_page to prepare for batched-lock insert Andrew Morton
2020-04-10 21:32   ` Andrew Morton
2020-04-10 21:32 ` [patch 13/35] mm: bring sparc pte_index() semantics inline with other platforms Andrew Morton
2020-04-10 21:32 ` [patch 14/35] mm: define pte_index as macro for x86 Andrew Morton
2020-04-10 21:33 ` [patch 15/35] mm/memory.c: add vm_insert_pages() Andrew Morton
2020-04-10 21:33 ` [patch 16/35] mm/vma: define a default value for VM_DATA_DEFAULT_FLAGS Andrew Morton
2020-04-10 21:33   ` Andrew Morton
2020-04-10 21:33 ` [patch 17/35] mm/vma: introduce VM_ACCESS_FLAGS Andrew Morton
2020-04-10 21:33 ` [patch 18/35] mm/special: create generic fallbacks for pte_special() and pte_mkspecial() Andrew Morton
2020-04-10 21:33 ` [patch 19/35] mm/memory_hotplug: drop the flags field from struct mhp_restrictions Andrew Morton
2020-04-10 21:33 ` [patch 20/35] mm/memory_hotplug: rename mhp_restrictions to mhp_params Andrew Morton
2020-04-10 21:33 ` [patch 21/35] x86/mm: thread pgprot_t through init_memory_mapping() Andrew Morton
2020-04-10 21:33 ` [patch 22/35] x86/mm: introduce __set_memory_prot() Andrew Morton
2020-04-10 21:33 ` [patch 23/35] powerpc/mm: thread pgprot_t through create_section_mapping() Andrew Morton
2020-04-10 21:33 ` [patch 24/35] mm/memory_hotplug: add pgprot_t to mhp_params Andrew Morton
2020-04-10 21:33 ` [patch 25/35] mm/memremap: set caching mode for PCI P2PDMA memory to WC Andrew Morton
2020-04-10 21:33 ` [patch 26/35] kmod: make request_module() return an error when autoloading is disabled Andrew Morton
2020-04-10 21:33 ` [patch 27/35] fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once() Andrew Morton
2020-04-10 21:33 ` Andrew Morton
2020-04-10 21:33 ` Andrew Morton [this message]
2020-04-10 21:33 ` [patch 29/35] selftests: kmod: fix handling test numbers above 9 Andrew Morton
2020-04-10 21:33 ` [patch 30/35] selftests: kmod: test disabling module autoloading Andrew Morton
2020-04-10 21:34 ` [patch 31/35] change email address for Pali Rohár Andrew Morton
2020-04-10 21:44   ` Joe Perches
2020-04-10 21:34 ` [patch 32/35] drivers/dma/tegra20-apb-dma.c: fix platform_get_irq.cocci warnings Andrew Morton
2020-04-13 17:54   ` Jon Hunter
2020-04-10 21:34 ` [patch 33/35] fs/seq_file.c: seq_read(): add info message about buggy .next functions Andrew Morton
2020-04-10 21:34 ` [patch 34/35] kernel/gcov/fs.c: gcov_seq_next() should increase position index Andrew Morton
2020-04-10 21:34 ` [patch 35/35] ipc/util.c: sysvipc_find_ipc() " Andrew Morton

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200410213350.o21mcrRmh%akpm@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=ast@kernel.org \
    --cc=ebiggers@google.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jeffv@google.com \
    --cc=jeyu@kernel.org \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mcgrof@kernel.org \
    --cc=mm-commits@vger.kernel.org \
    --cc=neilb@suse.com \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.