usecase: two sd cards are being mounted in parallel at same time on
dual core. example modules which are getting loaded is nls_cp437.
While one module is being loaded , it starts creating sysfs files.
meanwhile on other core, modprobe might return saying the module
is KMOD_MODULE_BUILTIN, which might result in not mounting sd card.
Experiments done to prove the issue in kmod.
Added sleep in kernel module.c at the place of creation of sysfs files.
Then tried `modprobe nls_cp437` from two different shells.
While the first was still waiting for its completion ,
the second one returned saying the module is built-in.
[ Lucas:
The problem is that the creation of /sys/module/<name> and
/sys/module/<name>/initstate are not atomic. There's a small window in
which the directory exists but the initstate file was still not
created.
Built-in modules can be handled by searching the modules.builtin file.
We actually lose some "modules" that create entries in /sys/modules
(e.g. vt) and are not in modules.builtin file: only those that can be
compiled as module are present in this file.
We enforce mod->builtin to always be up-to-date when
kmod_module_get_initstate() is called. This way if the directory
exists but the initstate doesn't, we can be sure this is because the
module is in the "coming" state, i.e. kernel didn't create the file
yet, but since builtin modules were already handled by checking our
index the only reason for that to happen is that we hit the race
condition.
I also added some tweaks to the patch, so we don't repeat the code for builtin
lookup. ]
It has changed in the past, and these days, anyone can get a copy of the
LGPL via the web rather than by post.
Like 657a122 (Remove FSF mailing address) in libabc by Josh Tripplet,
but let the FSF website in which the license can be found.
Before we had softdeps, the usual idiom was
install foo /sbin/modprobe bar; /sbin/modprobe --ignore-install foo
ignoring errors from the first modprobe invocation. This also matches
the behavior of module-init-tools' implementation of softdep.
There are several exported enums by libkmod without document, this patch
mainly added documentation for below enums like the way kmod_resources
be documented in.
* kmod_index
* kmod_remove
* kmod_insert
* kmod_probe
* kmod_filter
* kmod_module_initstate
This is not the best way to document these exported enums, however, it's
the simple way due to gtkdoc limits. It doesn't support export plain
enum like below: see https://bugzilla.gnome.org/show_bug.cgi?id=657444
---------8<-------head.h--------------8<-----------
...
enum foo {
...
};
...
---------8<-------end of head.h-------8<-----------
---------8<-------source.c------------8<-----------
...
/**
* document for foo here
*/
...
typedef enum foo foo;
...
---------8<-------end of source.c-----8<----------
Add __attribute__((format)) to log_filep() and _show() functions, fixing
the bugs they found in the source code.
For functions that receive va_list instead of being variadic functions
we put 0 in the last argument, so at least the string is checked and we
get warnings of -Wformat-nonliteral type. So, it's better than adding a
pragma here to shut up the warning.
"The secure_getenv() function is intended for use in general-purpose
libraries to avoid vulnerabilities that could occur if set-user-ID or
set-group-ID programs accidentally trusted the environment."
This is a broken option that only leads to misery and incompatabilities
with other systems. Kbuild doesn't come close to supporting directories
other than /lib/modules with several targets simply failing without
hacky fixes. Simply remove the option and all traces of it, as it
doesn't make sense in today's world.
It makes more sense to have libkmod-config.c deal with the configuration
directly and the others get the config from ctx. As a bonus point we get
a smaller binary. Following numbers are for x86-64, libkmod + kmod:
Before:
text data bss dec hex filename
128840 1496 104 130440 1fd88 tools/modprobe
After:
text data bss dec hex filename
128392 1496 104 129992 1fbc8 tools/modprobe
This reverts commit 88a170dbd6.
There's no reason for users of the API to call this method, it's just
wrong to export it.
The bug that this patch fixed needs to be fixed another way, not
exporting this function.
If we don't have --gc-sections support, linking kmod fails:
libkmod/.libs/libkmod-util.a(libkmod-util.o): In function 'underscores':
libkmod/libkmod-util.c:117: undefined reference to 'kmod_log'
This is because kmod_log is missing the export define, even though it's
already listed in the exported symbol list.
This matches the change in systemd and udev. Log message on udev's
change by Kay Sievers:
After long consideration we came to the conclusion that user
configuration in /etc should always override the (generally
computer generated) configuration in /run. User configuration
should always be what matters over anything else. Hence rearrange
the search orders accordingly. In general this should change
very little as overriding like this is seldomn done so far,
and the order between /etc and /usr stays the same.
Search modules.builtin file before saying the module was not found.
Note: these "modules" should not appear as dependencies of other modules
(in modules.dep) even if they appear in modinfo. This fixes the return
code of modprobe with builtin modules.
Also fixes a small coding style issue in module_is_inkernel().
Just printing the errno string such as "%m\n" is not enough to help
debug or users understand the problem.
Change to provide more context on the failing operation.
Some messages may happen more than once in the same function and
discovering the line is hard. Now we print the actual log priority
that exposed the message as well as filename and line.
NOTE: We should consider printing the log priority in the non-debug
version as well.
This field can be used to iterate the modules, controlling whether we
are revisiting a certain module. A function to clear the values in all
modules is needed since when we are iterating, we don't know if the
module is created anew or if it's picked from the pool. Therefore we
can't know if the field is true because of a previous iteration or if
the module was indeed already visited.
Not all libc's have a mtim member in struct stat (dietlibc doesn't).
Change ts_usec() to receive a struct stat as parameter and implement it
accordingly for both cases.
Index dump doesn't use stdio.h function and instead call write()
directly on STDOUT_FILENO file descriptor. Therefore we need to flush
stdio buffers before calling it, to be sure the configuration dump will
appear before index's.
Provide a function to dump the index files to a certain fd. It could be
more optimized (particularly the functions to dump the index that were
copied and pasted from m-i-t), but it seems like the only user of it is
'modprobe -c', used for debugging purposes. So, keep it as is.
Lucas De Marchi
Harish Jenny K N
Leandro Pereira
Michal Marek
Chengwei Yang
Lucas De Marchi
Cristian Rodríguez
Lucas De Marchi
Dave Reisner
Mike Frysinger
Gustavo Sverzut Barbieri
Kay Sievers