Issue #1124 ("Jump label issues are triggered from an unrelated
function") was caused by a minor __LINE__ change in a pr_warn statement.
Reference it here in the author guide for future reference.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
The modpost step complains about one of our generated files, output.o
and that it can't find a corresponding .cmd file for it (full path names
stripped):
WARNING: could not find .output.o.cmd for output.o
This was turned into an error in v5.8:
.output.o.cmd: No such file or directory
Avoid this by creating an empty .cmd file so that modpost acknowledges
that the file exists, but doesn't parse anything out of it.
Fixes#1125
Reported-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> (for v5.8+)
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Fail the kpatch build, while attempted to build on unsupported
architecture. The build will eventually fail but with the error that
doesn't hint the user clearly about the support status of kpatch, on the
architecture. This patch forces the build error with the message about
the unsupported status, avoiding confusion to the user.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
The commands used to build the livepatches and to load or unload them
are currently hard-coded in kpatch-test.
This patch adds 2 options to kpatch-test to make it easier to use custom
kpatch and kpatch-build commands:
* --system-kpatch-tools - if set, 'sudo kpatch' will be used to
load/unload the patches; 'kpatch-build' - to build them.
To use custom tools here, the user can adjust $PATH.
If the option is not set, kpatch-test will assume it is in kpatch source
tree, same as before this commit, and will use the tools from there.
* --kpatch-build-opts="..." - additional options to pass to
kpatch-build.
Example:
./kpatch-test \
--system-kpatch-tools \
--kpatch-build-opts="-s ./linux-src -c ./config -v ./vmlinux" \
-d my_kpatch_tests/test/integration/v01
In this case, kpatch and kpatch-build installed in the system will be used,
and kpatch-build will look for the kernel source tree, configuration
file and vmlinux binary in the current directory.
Signed-off-by: Evgenii Shatokhin <eshatokhin@virtuozzo.com>
Before kpatch-build would only keep build.log with --debug option
specified, but it also makes sense to keep it if --skip-cleanup is
specified.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
RHELs older than 7.7 are missing 5279631271b3 "module: fix ddebug_remove_module()"
which leads to a crash if dynamic debug is used with livepatching.
Disable recent dynamic debug addition on those distros.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
On x86, .altinstr_aux is used to store temporary code which allows
static_cpu_has() to work before apply_alternatives() has run. This code
is completely inert for modules, because apply_alternatives() runs
during module init, before the module is fully formed. Any changed
references to it (i.e. changed addend) can be ignored. As long as
they're both references to .altinstr_aux, they can be considered equal,
even if the addends differ.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Linux kernel tristate config options allows selected feature, either to
be built-in to the kernel or to be built as a kernel module. When built
as a kernel module, it's expected that the module, will be built with
module information such as author, license, description and others.
For each of the modinfo, a corresponding __UNIQUE_ID_ symbol is
generated. Their lookup succeeds in the case of module but fails when
selected to built-in to the kernel, the reason being that the kernel
discards these __UNIQUE_ID_ symbols during linking. Add __UNIQUE_ID_
symbols to maybe_discarded_sym list, to avoid failure in case of
table->object is vmlinux.
i.e.:
# cat .config|grep IOSCHED_BFQ (can be compiled as module too)
CONFIG_IOSCHED_BFQ=y
# readelf -sW ./block/bfq-iosched.o|grep UNIQUE
219: 0000000000000000 54 OBJECT LOCAL DEFAULT 267 __UNIQUE_ID_description223
220: 0000000000000036 16 OBJECT LOCAL DEFAULT 267 __UNIQUE_ID_license222
221: 0000000000000046 19 OBJECT LOCAL DEFAULT 267 __UNIQUE_ID_file221
222: 0000000000000059 25 OBJECT LOCAL DEFAULT 267 __UNIQUE_ID_author220
223: 0000000000000072 22 OBJECT LOCAL DEFAULT 267 __UNIQUE_ID_alias219
the line below before the kpatch error, is a debug printf to find the failing lookup symbol:
Failed lookup for __UNIQUE_ID_description223
/root/kpatch/kpatch-build/create-diff-object: ERROR: bfq-iosched.o: find_local_syms: 180: couldn't find matching bfq-iosched.c local symbols in ./vmlinux symbol table
with the patch, it successfully builds with both y/m config options:
...
bfq-iosched.o: changed function: bfq_idle_slice_timer
Patched objects: vmlinux
Building patch module:
livepatch-0001-block-bfq-fix-use-after-free-in-b.ko
SUCCESS
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Kernel livepatching modules build on GCC 10, with patched functions
referring to local function would fail to load with the error:
module_64: livepatch_ext4_cond_resched: Expected nop after call, got 7fe5fb78 at ext4_setup_system_zone+0x460/0xc90 [livepatch_ext4_cond_resched]
for more details on the error, refer to discussion at:
https://lkml.kernel.org/r/1508217523-18885-1-git-send-email-kamalesh@linux.vnet.ibm.com
the reason was that the gcc-plugin would skip the pass on error, failing
to convert the local calls into global, i.e on ppc64le every global call
is followed by a nop instruction, that gets replaced by the kernel to
restore
the TOC/r2 value of the callee, while parsing the relocations and would
skip the TOC restoration for local functions, where the TOC remains the
same across sibling functions.
GCC 10 commit 07c48b61a082("[RS6000] Put call cookie back in AIX/ELFv2
call patterns") merged a couple of call codes definition, breaking the
plugin. Change the plugin codes to match the GCC 10 codes.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Abort building the klp module, if the code for local and non-local calls
are not found instead of skipping the pass and building module, which
might result in un-loadable module with the kernel error:
module_64: livepatch_ext4_cond_resched: Expected nop after call, got 7fe5fb78 at ext4_setup_system_zone+0x460/0xc90 [livepatch_ext4_cond_resched]
gcc would not allow me to use "can't" in the error message and throw
build error:
gcc-plugins/ppc64le-plugin.c:49:17: error: contraction ‘can't’ in format; use ‘cannot’ instead [-Werror=format-diag]
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Building on Fedora 32 with GCC 10.1.1, triggers build failures:
In file included from gcc-plugins/ppc64le-plugin.c:1:
gcc-plugins/gcc-common.h:37:10: fatal error: params.h: No such file or directory
37 | #include "params.h"
| ^~~~~~~~~~
compilation terminated.
In file included from gcc-plugins/ppc64le-plugin.c:1:
gcc-plugins/gcc-common.h:841:13: error: redefinition of ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’
841 | inline bool is_a_helper<const ggoto *>::test(const_gimple gs)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from gcc-plugins/gcc-common.h:124,
from gcc-plugins/ppc64le-plugin.c:1:
/usr/lib/gcc/ppc64le-redhat-linux/10/plugin/include/gimple.h:1037:1:
note: ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const ggoto*]’ previously declared here
1037 | is_a_helper <const ggoto *>::test (const gimple *gs)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from gcc-plugins/ppc64le-plugin.c:1:
gcc-plugins/gcc-common.h:848:13: error: redefinition of ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const greturn*]’
848 | inline bool is_a_helper<const greturn *>::test(const_gimple gs)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from gcc-plugins/gcc-common.h:124,
from gcc-plugins/ppc64le-plugin.c:1:
/usr/lib/gcc/ppc64le-redhat-linux/10/plugin/include/gimple.h:1489:1:
note: ‘static bool is_a_helper<T>::test(U*) [with U = const gimple; T = const greturn*]’ previously declared here
1489 | is_a_helper <const greturn *>::test (const gimple *gs)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
as per kernel commit c7527373fe28 ("gcc-common.h: Update for GCC 10")
"params.h header file has been dropped from GCC 10 and is_a_helper()
macro is now defined in gimple.h"
this patch fix them by guarding the both param.h header file and
is_a_helper() with #ifdef checking for gcc version < 10000.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Fixing the remaining warnings suggesting to quote the output subshell
invocation would hinder readability. Also the results of dirname and
"type -p" used in the subshell should return spaceless strings in kpatch
usecases.
Ignore the warnings for now.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
It wouldn't be bash without pondering over what to quote or not to
quote.
Shellcheck reports a bunch of quoting issues in our scripts. Fix what
can be fixed.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Shellcheck emits the following warning:
SC2044: For loops over find output are fragile. Use find -exec or a while read loop.
Disable it for now.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Shellchecks warns about two useless commands:
SC2005: Useless echo? Instead of 'echo $(cmd)', just use 'cmd'.
SC2002: Useless cat. Consider 'cmd < file | ..' or 'cmd file | ..' instead.
Simplify that line with those suggestions.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Shellcheck emmits the following warning:
SC2035: Use ./*glob* or -- *glob* so names with dashes won't become options.
Which seems like a fair recommendation.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Shellcheck reports the following error:
SC2145: Argument mixes string and array.
Lets pretend that types are a thing in bash and use the list of
arguments as a single string instead of the array of arguments.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Shellcheck complains with the following warning:
SC2230: which is non-standard.
It is probably fair to assume that which is available for now, so just
ignore the warning.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Shellcheck complains with the following warning:
SC1091: Not following: /etc/os-release was not specified as input (see shellcheck -x)
Which is already silenced in lib.sh.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
A bash script is available to automatically install necessary
dependencies for building/using kpatch on some distributions.
Update the README sections for those distributions to use that script.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
On RHEL-8, version agnostic python-devel package does not exist.
On previous RHEL releases, python-devel is for python2.
On RHEL-8, the platform-python (which provides the needed utilities)
is python3.
Assuming this will be the same for future RHEL releases, specify the
python major as part of the kpatch dependencies.
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Enable dynamic debug prints in klp_try_switch_task() function before
going through with load tests and switch back to a previous state
afterwards.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
For consistency, disable the shadow-newpid-LOADED integration test
script since its corresponding patch already is already disabled.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Add the __mcount_loc section on ppc64le. It has pointers to all the
mcount calls. This will enable the ftrace hook to be used for patched
functions.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> (rebased)
Patches rebased against RHEL-8.2 GA kernel-4.18.0-193.el8.
Tests disabled for errors when building against updated
4.18.0-193.3.1.el8_2.x86_64 z-stream kernel:
* data-read-mostly.patch:
dev.o: Found a jump label at __netif_receive_skb_core()+0x32, using key netstamp_needed_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
dev.o: Found a jump label at __netif_receive_skb_core()+0x95, using key generic_xdp_needed_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
dev.o: Found a jump label at __netif_receive_skb_core()+0xd0, using key ingress_needed_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
dev.o: Found a jump label at __netif_receive_skb_core()+0x412, using key nf_hooks_needed. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
/root/github-kpatch/kpatch-build/create-diff-object: ERROR: dev.o: kpatch_regenerate_special_section: 2344: Found 4 jump label(s) in the patched code. Jump labels aren't currently supported. Use static_key_enabled() instead.
* gcc-static-local-var-4.patch (ppc64le only):
aio.o: Found a jump label at aio_free_ring()+0x7c, using key devmap_managed_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
/root/github-kpatch/kpatch-build/create-diff-object: ERROR: aio.o: kpatch_regenerate_special_section: 2344: Found 1 jump label(s) in the patched code. Jump labels aren't currently supported. Use static_key_enabled() instead.
* shadow-newpid.patch:
fork.o: WARNING: unable to correlate static local variable ctr.70325 used by _do_fork, assuming variable is new
fork.o: changed function: _do_fork
exit.o: Found a jump label at do_exit()+0x6d3, using key devmap_managed_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
/root/github-kpatch/kpatch-build/create-diff-object: ERROR: exit.o: kpatch_regenerate_special_section: 2344: Found 1 jump label(s) in the patched code. Jump labels aren't currently supported. Use static_key_enabled() instead.
* special-static.patch:
fork.o: Found a jump label at copy_process.part.34()+0x1fc, using key memcg_kmem_enabled_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
fork.o: Found a jump label at copy_process.part.34()+0x21b, using key memory_cgrp_subsys_enabled_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
fork.o: Found a jump label at copy_process.part.34()+0x72a, using key memory_cgrp_subsys_enabled_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead.
fork.o: Found a jump label at copy_process.part.34()+0x773, using key memcg_kmem_enabled_key. Jump labels aren't supported with this kernel. Use static_key_enabled() instead
./root/github-kpatch/kpatch-build/create-diff-object: ERROR: fork.o: kpatch_regenerate_special_section: 2344: Found 4 jump label(s) in the patched code. Jump labels aren't currently supported. Use static_key_enabled() instead.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
