The kpatch utility is now user friendly enough that it can be used
instead of direct insmods. We should encourage people to use it, since
we will soon be adding user space functionality above and beyond
insmod/rmmod when loading and unloading.
Allow "kpatch load" to find the core module when kpatch is run directly
from the git tree. This gives the user the option to use the kpatch
utility directly without having to do a "make install".
While debugging the code for the bug table logic, I found it useful to
know which rela section and entry the error occurred on.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
This commit adds a new function to properly handle the bug table.
It works by going through .rela__bug_table, after the changed
function symbols have already been marked, and rewrites the section
including only the relocations pertaining to bug entries for
changed functions.
The __bug_table section itself is not modified resulting in
"blank" bug entries: ones whose IP and filename pointers will
not be relocated and, therefore, will be zero. While a waste
of space, it simplifies the code not to remove these blank
entries. They do no harm.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
The section header size is calculated at output time by libelf
and we use it as a read-only value from read files.
With the next patch we are changing the size of the .rela__bug_table
section. Lets use d_size instead since it is the value that tells
libelf how to calculate sh_size at output time.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
Allow bundling of .bss.* sections that are the result of -fdata-sections
so that rela sections referencing data in bss sections by section symbol
can be replaced with the object symbol so it can be linked to the existing
data object in the kernel.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
For log_normal and DIFF_FATAL messages, prefix them with the object name
to give more context, which is useful for patches which change multiple
objects. Also, no need to add the function and line number to
DIFF_FATAL messages, as the error strings already give enough
information.
Example messages:
meminfo.o: changed function: meminfo_proc_show
cmdline.o: no changed functions were found
A user may want to load a module without having to install it to the
initrd. In fact, 99% of the time I think that will be the typical usage
of "kpatch load", with a given file as an argument rather than a DB
module.
Have "kpatch load" and other commands take a file as input. If the file
is not found, then check the DB.
Try to be more consistent with the terminology. In various places we
call it a "hotpatch module", "hot patch module", or "patch module". How
about we just call it a "patch module" everywhere?
For now, taint with TAINT_USER when loading a patch module so that the
user can always detect when a kpatch module has been previously loaded.
Eventually we will want a dedicated TAINT_KPATCH flag in the kernel.
Unforunately the dracut module doesn't work if installed in
/usr/local/lib/dracut. It must always be installed in
/usr/lib/dracut regardless of the install prefix.
This reverts commit ab29b1ff59.
Reverting this commit because it causes kpatch-build to ignore any
errors reported by create-diff-object, treating all errors as meaning
that no changes occurred, which is a dangerous assumption to make.
Consider following patch: https://lkml.org/lkml/diff/2014/1/7/637/1
Kpatch-build will generate two objects for it. however mlock.o has no
changed function and will cause kpatch-build die.
Signed-off-by: Madper Xie <cxie@redhat.com>
After removing the distinction between 'enabled' modules and 'applied'
modules in 022e42bc, we can change the 'apply' and 'remove' subcommands,
to more intuitive 'load' and 'unload' subcommands.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
