When patching kernel module dm-persistent-data, I found
that the KOBJFILE_NAME is incorrectly replaced to
dm_persistent-data while the module name in kernel is
dm_persistent_data.
Signed-off-by: Zhipeng Xie <xiezhipeng1@huawei.com>
The kpatch.ko support module is no longer needed by modern upstream and
recent distribution kernels, so update the patch author guide
accordingly.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
kpatch-build doesn't support GCC's sibling call optimizations in patched
functions to avoid potentially dangerous generated code. Explain the
error message that may result and link to the commit which provided
detailed explanation of why we disabled support for this in kpatch.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
The kernel's definition of "inline" implies "notrace" and that may lead
to unexpected kpatch-build errors. Explain why that is and how to work
around the issue.
Fixes#983.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
The current code to find the twin of a local static variable allows two
variables of the same name to be wrongly matched with the other's twin.
While there isn't a magic formula to avoid this, make stricter
requirements for twining static local from the original object with
a symbol from the patched object. This reduces the risk of erroneous
matches.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Referenced kernel documentation has moved from txt file to rst. Update
the hyperlink to point to the correct file.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Process the debug sections only after all the other inclusion logic has
finished, since it makes decisions based on what else has already been
included.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
new-function test fails on ppc64le with the following message:
create-diff-object: ERROR: n_tty.o: kpatch_no_sibling_calls_ppc64le: 3445: Found an unsupported sibling call at n_tty_write()+0x20. Add __attribute__((optimize("-fno-optimize-sibling-calls"))) to n_tty_write() definition.
Add the suggested attribute, as was done for rhel-7.[5-7] versions of
the test.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
On ppcle64, test gcc-static-local-var-4 impacts a jump label reference
which is currently unsupported.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Jump labels are unsupported, so tests modifying functions using them are
expected to fail. So disable them, for now...
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Rebase the integration test cases on top of RHEL 8.0 kernel version
4.18.0-80.el8.
Suggested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
[JT: adapt data-new-LOADED to new meminfo format,
use common template for multiple.test]
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Disabled patches won't trigger a build, but the combined load test
will still attempt to run their associated LOADED.test script. The
combined test will fail due to voluntarily disabled tests.
Do not run tests scripts associated with disabled tests.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Simplify static local variable correlation and renaming code by using
the newly introduced helpers for section and symbol correlation.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Change 935f199875 ('create-diff-object: simplify mangled function
correlation') simplified the way symbols are correlated and got rid of
symbol section renaming.
As a result a symbol/section can now have a CHANGED status, being
correlated to an element that doesn't have the exact same name. This
will cause lookups to the original object fail when creating the new
patch object.
So lets bring back the symbol/section renaming, but only once they
have actually been correlated.
Fixes: 935f199875 ('create-diff-object: simplify mangled function
correlation')
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Elements from the original object and the patched object can be
correlated using their mangled names. In case an elements (section or
symbol) could be matched with more than one object through mangling,
make sure all elements related to a section are correlated with the
corresponding elements of the twin section.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
When freeing a kpatch_elf, another object might have symbols and
sections twined with elements that are getting freed.
Clear the twin references, so if they are used after the object they
reference is freed, the program will crash.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Kernel commit cb9b55d21fe0 modpost: add support for symbol namespaces
adds a new namespace column to Module.symvers file which can be blank.
fscanf is no longer a viable solution to parse that. Switch to the way
scripts/mod/modpost.c handles this and try to support both versions with
and without namespace column.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Currently, only rela section get freed. This seems like a simple
scope mistake.
Free all sections regardless of their nature in kpatch_elf_teardown()
Signed-off-by: Julien Thierry <jthierry@redhat.com>
The unload_all() function in kpatch-test script is out dated and
does not unload patches loaded through livepatching.
Luckily, "kpatch unload --all" should support both kpatch unloading
kpatch patches and livepatch patches.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Some versions of Linux livepatching require patches to be unloaded
in the opposite order than the order they were loaded. Currently
kpatch simply goes through the list of sysfs livepatch directories
and tries to disable them one by one. This makes the following fail:
$ kpatch load a.ko
$ kpatch load b.ko
$ kpatch unload --all
kpatch: failed to unload module b
Since kpatch is not bound to a version of Linux, cater for those version
that do not support random unloading order, even for patches that do not
depend on one another.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
If an error occurs while loading a module or one of the tests,
multiple.test will exit leaving the working modules loaded. This leaves
the system in an unwanted state and causes the test that previously pass
to fail (succeeding before being loaded for multiple.test's point of
view).
Cleanup the loaded modules before exiting due to errors.
Also take this opportunity to factorize the test for the different
distros.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
The stacktrace internal interface has been updated for v5.2. On x86,
among others, this means that stack_trace_save_tsk* is to be used
instead of instantiating a stack_trace struct. Those routines are
currently not exported for module use.
See linux kernel: <25e39e32b0a3> (livepatch: Simplify stack trace retrieval)
for more info about the stacktrace interface changes.
The kernel/livepatch subsystem is the way forward for using kpatch and
there are plans to phase out 'kmod' altogether in the near future.
It is still possible to build and use kmod by doing something like:
$ env BUILDMOD="yes" make
Closes#966
Signed-off-by: Yannick Cote <ycote@redhat.com>
The RHEL powerpc kernel is compiled with -O3, which triggers some
"interesting" new optimizations. One of them, which seems to be
relatively common, is the replacing of a function with two separate
"constprop" functions.
Previously we only ever saw a single constprop clone, so we just renamed
the patched version of the function to match the original version. Now
that we can have two such clones, that no longer makes sense.
Instead of renaming functions, just improve the correlation logic such
that they can be correlated despite having slightly different symbol
names. The first clone in the original object is correlated with the
first clone in the patched object; the second clone is correlated with
the second clone; and so on.
This assumes that the order of the symbols and sections doesn't change,
which seems to be a reasonable assumption based on past experience with
the compiler. Otherwise it will just unnecessarily mark the cloned
constprop functions as changed, which is annoying but harmless, and
noticeable by a human anyway.
Fixes#935.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Building a kpatch for a module with this Makefile:
The Makefile is as follow:
obj-m += m_hello.o
m_hello-y = hello.o
default:
$(MAKE) -C /lib/modules/4.4.21-69-default/build M=$(shell pwd) modules
clean:
$(MAKE) -C /lib/modules/4.4.21-69-default/build M=$(shell pwd) clean
results in kpatch-build "ERROR: two parent matches for hello.o".
The problem is that find_parent_obj() looks for filenames like so:
% grep -l hello.o ./.*.cmd | grep -Fv hello.o
.m_hello.ko.cmd
.m_hello.o.cmd
where .m_hello.ko.cmd is the parant for m_hello.o, and .m_hello.o.cmd is the
parant for hello.o, but because the "hello.o" is a substring of "m_hello.o",
it will cause "m_hello.o" to be matched for the "hello.o" as well.
Fix this by using grep's -w|--word-regexp option to force it to match
whole words instead of substrings.
Signed-off-by: chenzefeng <chenzefeng2@huawei.com>
When these from internal depths of Red Hat upstream paths changed and
now we are one level deeper in directory tree.
The issue probably also exist in rhel8.0 rebase pr #993.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
If the symbol associated with a relocation does not have a section set,
nothing is done for that relocation.
Skip iterating through all the symbols of the ELF file in such a case.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
rela_insn() only retrieves information about an instruction and does not
modify sections or relocations.
Add const to make this explicit.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
There is no point inspecting through the symbols of the ELF files
(original and patched) when the ELF headers do not meet requirements.
Check ELF headers as soon as the files are mapped.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
We are seeing the following error on a real world patch:
unsupported reference to special section __barrier_nospec_fixup
The kpatch commit bb444c2168 ("create-diff-object: Check for *_fixup
sections changes") created this error because we were trying to be
future proof. However, that may have been overly paranoid, as it
doesn't seem likely that those fixup sections will need relocations
anytime soon, because the replacement instructions are manually
generated in code. And anyway that "future proof" commit breaks the
present.
Also we decided at LPC that we are going to remove .klp.arch sections
anyway, so once that happens we will be fully future-proof anyway.
This reverts commit bb444c2168.
Fixes#974.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Somewhere starting with 5.3 (probably with 9f69a496f100 "kbuild: split
out *.mod out of {single,multi}-used-m rules", but that is not
confirmed) .mod and correcponding .mod.cmd files started showing up
during module builds throwing off kpatch-build's find_parent_obj() func.
Filter out any files ending with .mod.cmd as they are definitely not the
parent.
Signed-off-by: Artem Savkov <artem.savkov@gmail.com>
Not every distro out there supports /etc/os-release file.
This file is useful for obtaining given distro defaults, but not
essential for the script to work (when all parameters are passed
on a command line).
To avoid warnings or unwanted errors, make sourcing of this file
conditional.
Signed-off-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
