Pull module updates from Rusty Russell:
"Main excitement here is Peter Zijlstra's lockless rbtree optimization
to speed module address lookup. He found some abusers of the module
lock doing that too.
A little bit of parameter work here too; including Dan Streetman's
breaking up the big param mutex so writing a parameter can load
another module (yeah, really). Unfortunately that broke the usual
suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
appended too"
* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
modules: only use mod->param_lock if CONFIG_MODULES
param: fix module param locks when !CONFIG_SYSFS.
rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
module: add per-module param_lock
module: make perm const
params: suppress unused variable error, warn once just in case code changes.
modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
kernel/module.c: avoid ifdefs for sig_enforce declaration
kernel/workqueue.c: remove ifdefs over wq_power_efficient
kernel/params.c: export param_ops_bool_enable_only
kernel/params.c: generalize bool_enable_only
kernel/module.c: use generic module param operaters for sig_enforce
kernel/params: constify struct kernel_param_ops uses
sysfs: tightened sysfs permission checks
module: Rework module_addr_{min,max}
module: Use __module_address() for module_address_lookup()
module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
module: Optimize __module_address() using a latched RB-tree
rbtree: Implement generic latch_tree
seqlock: Introduce raw_read_seqcount_latch()
...
Add a "param_lock" mutex to each module, and update params.c to use
the correct built-in or module mutex while locking kernel params.
Remove the kparam_block_sysfs_r/w() macros, replace them with direct
calls to kernel_param_[un]lock(module).
The kernel param code currently uses a single mutex to protect
modification of any and all kernel params. While this generally works,
there is one specific problem with it; a module callback function
cannot safely load another module, i.e. with request_module() or even
with indirect calls such as crypto_has_alg(). If the module to be
loaded has any of its params configured (e.g. with a /etc/modprobe.d/*
config file), then the attempt will result in a deadlock between the
first module param callback waiting for modprobe, and modprobe trying to
lock the single kernel param mutex to set the new module's param.
This fixes that by using per-module mutexes, so that each individual module
is protected against concurrent changes in its own kernel params, but is
not blocked by changes to other module params. All built-in modules
continue to use the built-in mutex, since they will always be loaded at
runtime and references (e.g. request_module(), crypto_has_alg()) to them
will never cause load-time param changing.
This also simplifies the interface used by modules to block sysfs access
to their params; while there are currently functions to block and unblock
sysfs param access which are split up by read and write and expect a single
kernel param to be passed, their actual operation is identical and applies
to all params, not just the one passed to them; they simply lock and unlock
the global param mutex. They are replaced with direct calls to
kernel_param_[un]lock(THIS_MODULE), which locks THIS_MODULE's param_lock, or
if the module is built-in, it locks the built-in mutex.
Suggested-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Change the struct kernel_param.perm field to a const, as it should never
be changed.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cut from larger patch)
Most code already uses consts for the struct kernel_param_ops,
sweep the kernel for the last offending stragglers. Other than
include/linux/moduleparam.h and kernel/params.c all other changes
were generated with the following Coccinelle SmPL patch. Merge
conflicts between trees can be handled with Coccinelle.
In the future git could get Coccinelle merge support to deal with
patch --> fail --> grammar --> Coccinelle --> new patch conflicts
automatically for us on patches where the grammar is available and
the patch is of high confidence. Consider this a feature request.
Test compiled on x86_64 against:
* allnoconfig
* allmodconfig
* allyesconfig
@ const_found @
identifier ops;
@@
const struct kernel_param_ops ops = {
};
@ const_not_found depends on !const_found @
identifier ops;
@@
-struct kernel_param_ops ops = {
+const struct kernel_param_ops ops = {
};
Generated-by: Coccinelle SmPL
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Junio C Hamano <gitster@pobox.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: cocci@systeme.lip6.fr
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Similarly to module_param_unsafe(), add the helper to be used by core
code wishing to expose unsafe debugging or testing parameters that taint
the kernel when set.
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Consolidate the various external const and non-const declarations of
__start___param[] and __stop___param in <linux/moduleparam.h>. This
requires making a few struct kernel_param pointers in kernel/params.c
const.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Resolve a missing-field-initializer warning, that is produced
by every reference to module_param_call, by using designated
initialization for the first field. That is enough to silence
the complaint.
The message is only seen when doing a W=2 build. I happened to be using gcc
4.8.3, but I think most versions would produce the warning when it is
enabled. It can either be silenced by using even a single designated
initializer as I did here, or providing values for all of the fields. Because
of the number of references to the macro, this change silences many warnings
in W=2 builds.
One instance of the full warning message looks like this:
/home/share/git/nn-mdr/include/linux/moduleparam.h:198:16: warning: missing
initializer for field ‘free’ of ‘struct kernel_param_ops’
[-Wmissing-field-initializers]
static struct kernel_param_ops __param_ops_##name = \
^
/home/share/git/nn-mdr/fs/fuse/inode.c:35:1: note: in expansion of macro
‘module_param_call’
module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
^
/home/share/git/nn-mdr/include/linux/moduleparam.h:56:9: note: ‘free’
declared here
void (*free)(void *arg);
Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Some driver might want to pass in an 64-bit value, so introduce
a module param type 'ullong'.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Ewan Milne <emilne@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The kernel passes any args it doesn't need through to init, except it
assumes anything containing '.' belongs to the kernel (for a module).
This change means all users can clearly distinguish which arguments
are for init.
For example, the kernel uses debug ("dee-bug") to mean log everything to
the console, where systemd uses the debug from the Scandinavian "day-boog"
meaning "fail to boot". If a future versions uses argv[] instead of
reading /proc/cmdline, this confusion will be avoided.
eg: test 'FOO="this is --foo"' -- 'systemd.debug="true true true"'
Gives:
argv[0] = '/debug-init'
argv[1] = 'test'
argv[2] = 'systemd.debug=true true true'
envp[0] = 'HOME=/'
envp[1] = 'TERM=linux'
envp[2] = 'FOO=this is --foo'
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Summary of http://lkml.org/lkml/2014/3/14/363 :
Ted: module_param(queue_depth, int, 444)
Joe: 0444!
Rusty: User perms >= group perms >= other perms?
Joe: CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2?
Side effect of stricter permissions means removing the unnecessary
S_IFREG from several callers.
Note that the BUILD_BUG_ON_ZERO((perm) & 2) test was removed: a fair
number of drivers fail this test, so that will be the debate for a
future patch.
Suggested-by: Joe Perches <joe@perches.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> for drivers/pci/slot.c
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This code makes a compile time type check that is optimized away. Clang
complains that it generates an unused function:
linux/kernel/panic.c:471:1: warning: unused function '__check_panic'
[-Wunused-function]
core_param(panic, panic_timeout, int, 0644);
^
linux/moduleparam.h:283:2: note: expanded from macro
'core_param'
param_check_##type(name, &(var)); \
^
<scratch space>:87:1: note: expanded from here
param_check_int
^
linux/moduleparam.h:369:34: note: expanded from macro
'param_check_int'
#define param_check_int(name, p) __param_check(name, p, int)
^
linux/moduleparam.h:349:22: note: expanded from macro
'__param_check'
static inline type *__check_##name(void) { return(p); }
^
<scratch space>:88:1: note: expanded from here
__check_panic
GCC won't complain for a static inline function but would if it was just
a static function.
Adding the unused attribute to the function declaration removes the warning.
Per request from Rusty Russell it is marked as __always_unused as the code
is meant to be optimized away.
This code works for both GCC and clang.
Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Currently the params.c code allows only two "set" functions to have
no arguments. If a parameter does not have an argument, then it
looks at the set function and tests if it is either param_set_bool()
or param_set_bint(). If it is not one of these functions, then it
fails the loading of the module.
But there may be module parameters that have different set functions
and still allow no arguments. But unless each of these cases adds
their function to the if statement, it wont be allowed to have no
arguments. This method gets rather messing and does not scale.
Instead, introduce a flags field to the kernel_param_ops, where if
the flag KERNEL_PARAM_FL_NOARG is set, the parameter will not fail
if it does not contain an argument. It will be expected that the
corresponding set function can handle a NULL pointer as "val".
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Commit 026cee0086 "params:
<level>_initcall-like kernel parameters" set old-style module
parameters to level 0. And we call those level 0 calls where we used
to, early in start_kernel().
We also loop through the initcall levels and call the levelled
module_params before the corresponding initcall. Unfortunately level
0 is early_init(), so we call the standard module_param calls twice.
(Turns out most things don't care, but at least ubi.mtd does).
Change the level to -1 for standard module_param calls.
Reported-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Add a 3rd arg, named "doing", to unknown-options callbacks invoked
from parse_args(). The arg is passed as:
"Booting kernel" from start_kernel(),
initcall_level_names[i] from do_initcall_level(),
mod->name from load_module(), via parse_args(), parse_one()
parse_args() already has the "name" parameter, which is renamed to
"doing" to better reflect current uses 1,2 above. parse_args() passes
it to an altered parse_one(), which now passes it down into the
unknown option handler callbacks.
The mod->name will be needed to handle dyndbg for loadable modules,
since params passed by modprobe are not qualified (they do not have a
"$modname." prefix), and by the time the unknown-param callback is
called, the module name is not otherwise available.
Minor tweaks:
Add param-name to parse_one's pr_debug(), current message doesnt
identify the param being handled, add it.
Add a pr_info to print current level and level_name of the initcall,
and number of registered initcalls at that level. This adds 7 lines
to dmesg output, like:
initlevel:6=device, 172 registered initcalls
Drop "parameters" from initcall_level_names[], its unhelpful in the
pr_info() added above. This array is passed into parse_args() by
do_initcall_level().
CC: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds a set of macros that can be used to declare
kernel parameters to be parsed _before_ initcalls at a chosen
level are executed. We rename the now-unused "flags" field of
struct kernel_param as the level. It's signed, for when we
use this for early params as well, in future.
Linker macro collating init calls had to be modified in order
to add additional symbols between levels that are later used
by the init code to split the calls into blocks.
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
module_param(bool) used to counter-intuitively take an int. In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.
This eliminates that code (though leaves the flags field in the struct,
for impending use).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
