Otherwise on recent distros it appends the errno to the error message,
like:
create-diff-object: ERROR: x86.o: kpatch_regenerate_special_section: 2633: Found 1 unsupported static call(s) in the patched code. Use KPATCH_STATIC_CALL() instead.: Success
which is not what we want in most cases.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Similar to jump labels, static calls aren't supported when the static
call key was originally defined in a module rather than in vmlinux.
Detect those cases and either remove them (in the case of tracepoints)
or error out.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Convert the hard-coded should_keep_jump_label() to a proper callback,
since static calls will need a similar filter.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Align the s390 special_section initializers to improve readability and
for consistency with the rest.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
kpatch_mangled_strcmp() only ignores the digits after the period, but in
the case of __UNIQUE_ID(), the symbol names have random digits before
the period due to the use of `__COUNTER__`. Make sure such symbols are
properly correlated.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Rewrite kobj_find() to deal with Linux 5.19, where the .cmd files use
object file paths relative to the .cmd file rather than relative to the
root of the kernel tree.
While at it, add several performance enhancements to prevent all
currently known deep finds.
This is all quite fiddly. But it works.
Fixes#1277.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
When patching an OOT module, the parent object is always the OOT module.
Hard-code that to prevent the need for any further special casing in
find_kobj() (e.g., commit 9143e88f16 ("kpatch-build: fix
find_parent_obj")).
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Fix build error seen on gcc (GCC) 12.1.1 20220507 (Red Hat 12.1.1-1):
g++ -MMD -MP -I../kmod/patch -Iinsn -Wall -Wsign-compare -Wno-sign-conversion -g -Werror -shared -I/usr/lib/gcc/ppc64le-redhat-linux/12/plugin/include -Igcc-plugins -fPIC -fno-rtti -O2 -Wall gcc-plugins/ppc64le-plugin.c -o gcc-plugins/ppc64le-plugin.so
In file included from /usr/include/features.h:490,
from /usr/include/bits/libc-header-start.h:33,
from /usr/include/stdio.h:27,
from /usr/lib/gcc/ppc64le-redhat-linux/12/plugin/include/system.h:46,
from /usr/lib/gcc/ppc64le-redhat-linux/12/plugin/include/gcc-plugin.h:28,
from gcc-plugins/gcc-common.h:6,
from gcc-plugins/ppc64le-plugin.c:1:
/usr/include/bits/error-ldbl.h:23:1: error: type of ‘error’ is unknown
23 | __LDBL_REDIR_DECL (error)
| ^~~~~~~~~~~~~~~~~
/usr/include/bits/error-ldbl.h:23:1: error: ‘int error’ redeclared as different kind of entity
23 | __LDBL_REDIR_DECL (error)
| ^~~~~~~~~~~~~~~~~
In file included from gcc-plugins/ppc64le-plugin.c:2:
/usr/include/error.h:31:13: note: previous declaration ‘void error(int, int, const char*, ...)’
31 | extern void error (int __status, int __errnum, const char *__format, ...)
| ^~~~~
make[1]: *** [Makefile:39: gcc-plugins/ppc64le-plugin.so] Error 1
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Clang FDO adds a new, ignorable ELF section, .llvm.call-graph-profile
Generalize to ignore all .llvm.*
Signed-off-by: Pete Swain <swine@google.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> [subject line]
While gcc puts strings in .strtab and .shstrtab sections,
llvm toolchain just uses .strtab.
Adapt kpatch to handle both styles.
Signed-off-by: Pete Swain <swine@google.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> [small changes]
If two sections want to be the same, they need to satisfy
two conditions:
1) the result of memcmp is zero, which means they
have the same content.
2) they have the same relocation entries.
In one specific situation, two sections have the same content.
But one section has relocation entries while the other one has
no relocation entries. For example, in X86, consider the
following code:
original code
```
__noreturn noinline int kpatch_func(void)
{
while(1) {};
}
```
patched code
```
__noreturn notrace noinline int kpatch_func(void)
{
asm(".byte 0xe8, 0x00, 0x00, 0x00, 0x00");
while(1){};
}
```
Since the original code has a fentry call, these two functions have
the same compile result. But obviously, they are different functions.
Currently, kpatch would not find their differences since the patched
code has no relocation entries.
For the situation that one section has relocation entries while the
other one doesn't have, it should be set to be changed directly.
Cooperated-by: Zongwu Li <lizongwu@huawei.com>
Signed-off-by: Longjun Luo <luolongjuna@gmail.com>
After patched, rela information for some sections could
disappear. For example, a function like the following:
"
notrace noinline static int version_proc_show(struct seq_file *m,
void *v)
{
return 0;
}
"
Apart from common rela entries, trace and return thunk mechanism
will generate rela information. Use `notrace` to remove the
effect of trace. Make CONFIG_RETHUNK=n can remove the effect of
return thunk.
Discovered-by: Zongwu Li <lizongwu@huawei.com>
Signed-off-by: Longjun Luo <luolongjuna@gmail.com>
For consistency with what the kernel does (and what we already do for
in-tree modules), if the file has any dashes ('-'), replace them with
underscores in the objname (aka KBUILD_MODNAME).
Fixes#1286.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
To support building out-of-tree kernel modules, the source tree prefix
is attempted to be stripped from change object file paths to make them
relative. However, if the path is already relative, the change can
strip a substring instead, resulting in build errors.
Ensure just the prefix is stripped instead of any substring.
Fixes: #1282
Fixes: 51a8fad34f ("Add support for building out-of-tree modules")
Recent toolchains only create a section symbol if it's needed, i.e. if
there's a reference to it. If there's a missing section symbol in
kpatch_create_intermediate_sections(), create one instead of erroring
out.
Fixes#1272.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
* Add s390 specific checks
* Identify patchable functions.
* Dont mark expolines as dynrelas. These expolines are always included
in final kernel module. This ensures that expoline functions and the
kernel itself are not too far apart and avoids out of range
relocation. However, this isnt a problem for other functions, as these
relocations are performed via R_390_PLT32DBL using gcc option
-mno-pic-data-is-text-relative.
* s390 maintains expoline tables to locate the expoline thunks. If
needed, the module loader could later replace these expoline thunks
with normal indirect branch. Each element in the expoline table is of 4
bytes. If there is a changed function in rela.s390_return*, then mark
that specific rela symbol as included. This is already performed in the
processing of special sections. Hence include it.
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
1. -mno-pic-data-is-text-relative prevents relative addressing between
code and data. This is needed to avoid relocation error when klp text
and data are too far apart
2. Avoid generation of LANCHOR symbols through -fno-section-anchors.
kpatch-build does not handle it well.
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
symtab_read tries to skip '.dynsym' symbol table and only
read '.symtab' symbol table. Newer readelf from binutils 2.37
now adds section names (see the diff):
--- vmlinux.symtab 2022-02-18 02:10:06.691220932 +0100
+++ vmlinux.symtab.new 2022-02-18 01:16:06.161210458 +0100
Symbol table '.dynsym' contains 1541 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000100000 0 SECTION LOCAL DEFAULT 1 .text
2: 00000000017a3ac0 4 OBJECT GLOBAL DEFAULT 19 sclp_console_pages
Symbol table '.symtab' contains 159980 entries:
Num: Value Size Type Bind Vis Ndx Name
- 41: 0000000001a93600 0 SECTION LOCAL DEFAULT 41
- 42: 0000000001a9c678 0 SECTION LOCAL DEFAULT 42
...
+ 41: 0000000001a93600 0 SECTION LOCAL DEFAULT 41 .dynsym
+ 42: 0000000001a9c678 0 SECTION LOCAL DEFAULT 42 .rela.dyn
...
54: 0000000000000000 0 FILE LOCAL DEFAULT ABS main.c
Simple matching of ".dynsym" in the line buffer is not enough anymore,
because it hits not just
Symbol table '.dynsym' contains 1541 entries:
line, but also
41: 0000000001a93600 0 SECTION LOCAL DEFAULT 41 .dynsym
skipping the rest of the file and leading to an error:
create-diff-object: ERROR: *.o: find_local_syms: 189: couldn't find matching
*.c local symbols in vmlinux symbol table
Limit matching only to lines containing "Symbol table" header.
This works with readelf from the binutils, as well as readelf from
elfutils (its output looks slightly different).
Symbol table [41] '.dynsym' contains 1541 entries:
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
If a section reference can't be converted to a symbol reference, error
out to try to prevent unexpected behavior later on.
There are a few sections for which a symbol is optional: .rodata and
string literal sections. Don't warn about those.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
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>
As I noticed, commit eaaced191 has added
partial support for openEuler.
This patch enables usage in openEuler like:
kpatch-build xxxx.patch
I test it in openEuler 21.09, for people who
want to use kpatch in openEuler, two more steps
are needed.
1) add repo source
source rpm package of openEuler kernel are put in
two places. One is
https://repo.openeuler.org/openEuler-21.09/source/
Another one is
https://repo.openeuler.org/openEuler-21.09/update/source/
The latter one is not inclued in rpm repo lists by default.
2) compile kernel with CONFIG_LIVEPATCH_PER_TASK_CONSISTENCY enabled
openEuler has its own strategy when trying to apply patches.
We can use the klp_enable_patch function only when
CONFIG_LIVEPATCH_PER_TASK_CONSISTENCY is enabled.
Signed-off-by: anatasluo <luolongjuna@gmail.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>
