rela_insn() only cares about the base section. Convert it to take a
non-rela section as its argument instead of a relasec.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Add support for R_X86_64_NONE. With an upstream kernel, it's quite
rare, only used for a few jump labels. With older kernels it was used
for fentry hooks. Either way, it should be treated like a PC-relative
relocation.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
It doesn't make sense to disassemble a data section. That just happened
to work by accident. PC-relative offsets only need adjusting when
associated with an instruction.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Several functions have a boolean semantic, but don't actually return
bool, which is confusing. Fix that.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Several functions expect to take a ".rela" section as an argument. Make
such cases more clear by renaming "sec" -> "relasec".
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
With '--debug', most of the xtrace output shows the reading of the
.config and Module.symvers files, which isn't very useful and floods the
rest of the xtrace output. Temporarily disable xtrace before reading
the files.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
The two versions are not the same (4.18.0-240.el8 vs. 4.18.0-284.el8).
But I am not quite sure which one is accurate. Remove the first one as the
second one is being used before this change.
Signed-off-by: Song Liu <song@kernel.org>
Debug sections are intended to refer to the patch module only. And in
fact, any debug section references to non-included symbols are stripped
in kpatch_include_debug_sections(). So there's no need for
need_dynrela() to even think about it.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
A seg fault was reported:
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7f18c8e in __strcmp_avx2 () from /lib64/libc.so.6
Missing separate debuginfos, use: dnf debuginfo-install elfutils-libelf-0.186-1.fc34.x86_64 zlib-1.2.11-26.fc34.x86_64
(gdb) bt
#0 0x00007ffff7f18c8e in __strcmp_avx2 () from /lib64/libc.so.6
#1 0x000000000040a0f7 in kpatch_is_core_module_symbol (name=0x0) at create-diff-object.c:3060
#2 0x000000000040a267 in need_dynrela (kelf=0x4669a0, table=0x92af30, sec=0x6d6b20, rela=0x8c7fd0) at create-diff-object.c:3117
#3 0x000000000040a4cc in kpatch_create_intermediate_sections (kelf=0x4669a0, table=0x92af30, objname=0x7fffffffcfc6 "vmlinux", pmod_name=0x7fffffffd020 "livepatch_a") at create-diff-object.c:3281
#4 0x000000000040c7c5 in main (argc=8, argv=0x7fffffffca48) at create-diff-object.c:3931
It happened because 'rela->sym->name' was NULL, and
kpatch_is_core_module_symbol() tried to dereference it.
Here's the corresponding relocation:
Relocation section [455] '.rela.debug_loclists' for section [454] '.debug_loclists' at offset 0xd0478 contains 2432 entries:
Offset Type Value Addend Name
...
0x000000000000aad6 X86_64_64 000000000000000000 +32 .LC55
...
That '.LC55' symbol lives in the following section:
[104] .rodata.btf_show_end_aggr_type.str1.8 PROGBITS 0000000000000000 00003ef0 00000021 1 AMS 0 0 8
The problem is that the symbol wasn't included in the output file
(though its corresponding section was). So it got zeroed by
kpatch_elf_teardown(), which was designed to trigger seg faults to help
find bugs like this.
The string literal sections which hold the '.LCx' string symbols are
already being included. Include their symbols as well.
Fixes#1257.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
The __LINE__ detection code looks for "printk", which on newer kernels
has been renamed to "_printk". Fix the check for newer kernels.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
For x86, we already check arg2 and arg3 for `__LINE__` immediate load
detection. For parity, do the same thing for the other two arches.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Previously, the name length was limited to 48 chars. This was then
prepended with "kpatch-" and a trailing NUL terminator to get to the 56
char limit for kernel module names. After some code rearrangement, the
48 char restriction was applied to the name after being prefixed with
kpatch-/livepatch-, limiting the length more than necessary. Increase
the name length limit back to 55 chars to restore the original limit.
Fixes: c0105ea467 ("kpatch-build: set default module prefix accordingly")
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Technically we don't support s390 yet, but it's coming soon and there's
no harm in merging this one early. In fact this came in handy for
testing my endian fixes with #1203.
Note it doesn't actually do anything since 'kelf->arch' can't actually
get set to 'S390' yet. But it should work nicely with #1203 as it
evolves.
This is based on the patch from C. Erastus Toe in #1243, though there
may still be a few outstanding issues to look at in that PR, based on
some of the code review comments.
Originally-by: C. Erastus Toe <ctoe@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
With s390 support coming, we'll soon have to worry about endianness
issues when doing cross-compiles and cross-arch unit tests. Make
insn_is_load_immediate() endian-agnostic.
Suggested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Using -a/--archversion to explicitly set target kernel version was not
allowed if the kernel source directory and/or path to vmlinux with debug
info were set. This seems too strict, however.
vmlinux with debug info is used during the build to get symbol data, the
size of special structures, GCC version used to build the kernel, and the
target kernel version. As it turned out, some kernels, e.g. the ones from
OpenSUSE and derivatives, contain all that data except the Linux version
string in the file with debug info for vmlinux. Instead, that string is
present in vmlinux itself but that file does not contain debug info.
A simple workaround is to allow specifying the target kernel version
explicitly using -a/--archversion even if --sourcedir and/or --vmlinux are
set. If vmlinux with debug info does contain the Linux version string and
the version is different, kpatch-build will report an error.
Signed-off-by: Evgenii Shatokhin <evgenii.shatokhin@openvz.org>
For ppc64le, if a rela goes through the .toc, it requires an extra level
of indirection. Use toc_rela() here to ensure it gets the rela we care
about. This will be needed for the upcoming patch which checks for
`__func__`.
For non-ppc64le arches, and for ppc64le relas which don't go through the
.toc, toc_rela() is a no-op which just returns the rela. So this is
harmless for non-.toc cases.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
The arch-specific versions of kpatch_line_macro_change_only() are mostly
duplicate code. Unify them into a single implementation.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
If the only reference to the `__dyndbg` section is through a jump table
entry, the section doesn't get included and the jump table relocations
end up with a dangling reference to an UNDEF section symbol.
Make sure jump table referenced dynamic debug symbols get their sections
included.
Fixes#1253.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Symbol indexes over 64k don't fit into st_shndx and are stored in
extended symbol table. Make sure we properly handle these cases. It is
not normally useful during kpatch builds but will come up if we start
diffing linked objects.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
libelf can read and write various architecture ELF files that may
differ from the host system. Instead of using preprocessor directives
to build architecture-specific code as per the current host, detect the
intended target architecture from the input ELF files.
Based-on: https://github.com/dynup/kpatch/pull/1179
Signed-off-by: Bill Wendling <morbo@google.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> [small tweaks]
The last part of kpatch_elf_open() calls kpatch_find_func_profiling_calls() to
find and set sym->has_func_profiling. However, only create-diff-object.c
requires sym->has_func_profiling, so remove the call from
kpatch_elf_open() and let the lone user, create-diff-object, provide and
call it as needed.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Ignore distro-specific checks if kernel source directory is supplied as a
command line argument to remove the distro-specific tunings during
cross-compilation.
Signed-off-by: Ruslan Bilovol <rbilovol@cisco.com>
Signed-off-by: Oleh Matiusha <oleh.matiusha@globallogic.com>
Introduce the ability to pick a CROSS_COMPILE environment variable for
specifying toolchain prefix for all gcc and binutils. To facilitate its
use, do not set the DISTRO variable when USERSRCDIR is specified.
Signed-off-by: Ruslan Bilovol <rbilovol@cisco.com>
Signed-off-by: Oleh Matiusha <oleh.matiusha@globallogic.com>
Commit 134ab5bd1883 ("objtool,x86: Replace alternatives with .retpoline_sites")
in the kernel starts keeping track of retpoline thunk call sites in a
dedicated section rather than via the alternatives mechanism.
The .retpoline_sites section needs to have its entries and relocations
for changed symbols included in the patch ELF when building for kernel
5.16+ with CONFIG_RETPOLINE=y.
Signed-off-by: Markus Boehme <markubo@amazon.com>
In kpatch-build, there are a number of places where a dynamic allocation
is performed, but the allocation is not checked for a failure. The
common pattern in kpatch-build is to check whether the returned pointer
is NULL, and if so, invoke the ERROR() macro to print a message and
abort the program.
kpatch_create_mcount_sections(), CORRELATE_ELEMENT(), and
create_klp_arch_sections() all had dynamic allocations without failure
checks. This diff adjusts those callsites to properly check for a failed
allocation, and ERROR() accordingly.
Signed-off-by: David Vernet <void@manifault.com>
find_special_section_data() and find_special_section_data_ppc64le() are
almost identical. Refactor the code so that a single function serves
both (and future) architectures without all the code duplication.
The inline awk script algorithm remains the same, only flip the "skip_x"
logic to "check_x" logic for readability.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Rather than individually (re)grepping the kernel configuration for
CONFIG_ options, source the entire file to import all the settings in
one shot.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
KPATCH_BUILD is used in kpatch-module build to specify the kernel
directory and thus needs to be set to KERNEL_SRCDIR, not BUILDDIR.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
kpatch-build currently initializes KBUILD_EXTRA_SYMBOLS to "", denying
users ability to set it themselves.
Fixes: #1238
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Previously OOT-module builds used `--sourcedir` to specify oot-module
source directory which was a bit confusing and also denied users ability
to build kpatches agains oot modules built against non-distro kernels.
This patch adds `-p/--oot-module-src` option to specify source dir for
oot module while keeping `--sourcedir` for kernel source directory
specification.
I also tried to disambiguate `SRCDIR` in kpatch-build a bit. Now there
are 3 variables:
- `KERNEL_SRCDIR` - contains path to kernel source directory
- `OOT_MODULEL_SRCDIR` - contains path to out-of-tree module source directory
- `BUILDDIR` - can be set to either of the above and is used for
patch-related actions
Another attempt at this was done by @omatiusha in #1234
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Upstream v5.14+ kernel change a358f40600b3 ("once: implement
DO_ONCE_LITE for non-fast-path "do once" functionality") consolidated a
bunch of do-once macros into a common macro:
#define DO_ONCE_LITE_IF(condition, func, ...) \
({ \
static bool __section(".data.once") __already_done; \
...
which replaced static local variable __warned with __already_done.
Update any __warned static local checks to also look for the new
__already_done variable as well.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
The kpatch-build script sets and exports a bunch of environment varibles
like KCFLAGS as well as data structure sizes in <STRUCT>_SIZE.
Dump the current environment to $CACHEDIR/tmp/kpatch-build.env so these
values can be more easily reused later:
% source <PATH>/kpatch-build.env && <command>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
RHEL-9 integration tests revealed that the kernel now makes use of
R_PPC64_REL64 relocations in the jump table, but need_dynrela() contains
code to specifically skip any R_PPC64_REL64 type when determining if a
relocation should be turned into dynrela.
Kamalesh Babulal explains:
I tried digging a little deeper and the upstream Kernel commit
b0b3b2c78ec (powerpc: Switch to relative jump labels) in v5.13,
introduced the change of generating relocation entries of type
R_PPC64_REL64, instead of absolute relocation type R_PPC64_ADDR64:
Relocation section '.rela__jump_table' at offset 0x1a87d8 contains 303 entries:
Offset Info Type Symbol's Value Symbol's Name + Addend
...
00000000000003c8 000007910000002c R_PPC64_REL64 0000000000000000 __tracepoint_netif_receive_skb + 8
...
Relax the existing check in need_dynrela() for .rela__jump_table
R_PPC64_REL64 relocations in case we need dynrelas for them.
Fixes: #1212
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
