There have been some recently reported ORC unwinder warnings like:
WARNING: can't access registers at entry_SYSCALL_64_after_hwframe+0x63/0xcd
WARNING: stack going in the wrong direction? at __sys_setsockopt+0x2c6/0x5b0 net/socket.c:2271
And a KASAN warning:
BUG: KASAN: stack-out-of-bounds in unwind_next_frame (arch/x86/include/asm/ptrace.h:136 arch/x86/kernel/unwind_orc.c:455)
It turns out the 'signal' bit isn't getting propagated from the unwind
hints to the ORC entries, making the unwinder confused at times.
Fixes: ffb1b4a410 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Reported-by: kernel test robot <oliver.sang@intel.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/97eef9db60cd86d376a9a40d49d77bb67a8f6526.1676579666.git.jpoimboe@kernel.org
Andi reported that objtool on vmlinux.o consumes more memory than his
system has, leading to horrific performance.
This is in part because we keep a struct instruction for every
instruction in the file in-memory. Shrink struct instruction by
removing the CFI state (which includes full register state) from it
and demand allocating it.
Given most instructions don't actually change CFI state, there's lots
of repetition there, so add a hash table to find previous CFI
instances.
Reduces memory consumption (and runtime) for processing an
x86_64-allyesconfig:
pre: 4:40.84 real, 143.99 user, 44.18 sys, 30624988 mem
post: 2:14.61 real, 108.58 user, 25.04 sys, 16396184 mem
Suggested-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210624095147.756759107@infradead.org
Currently objtool headers are being included either by their base name
or included via ../ from a parent directory. In case of a base name usage:
#include "warn.h"
#include "arch_elf.h"
it does not make it apparent from which directory the file comes from.
To make it slightly better, and actually to avoid name clashes some arch
specific files have "arch_" suffix. And files from an arch folder have
to revert to including via ../ e.g:
#include "../../elf.h"
With additional architectures support and the code base growth there is
a need for clearer headers naming scheme for multiple reasons:
1. to make it instantly obvious where these files come from (objtool
itself / objtool arch|generic folders / some other external files),
2. to avoid name clashes of objtool arch specific headers, potential
obtool arch generic headers and the system header files (there is
/usr/include/elf.h already),
3. to avoid ../ includes and improve code readability.
4. to give a warm fuzzy feeling to developers who are mostly kernel
developers and are accustomed to linux kernel headers arranging
scheme.
Doesn't this make it instantly obvious where are these files come from?
#include <objtool/warn.h>
#include <arch/elf.h>
And doesn't it look nicer to avoid ugly ../ includes? Which also
guarantees this is elf.h from the objtool and not /usr/include/elf.h.
#include <objtool/elf.h>
This patch defines and implements new objtool headers arranging
scheme. Which is:
- all generic headers go to include/objtool (similar to include/linux)
- all arch headers go to arch/$(SRCARCH)/include/arch (to get arch
prefix). This is similar to linux arch specific "asm/*" headers but we
are not abusing "asm" name and calling it what it is. This also helps
to prevent name clashes (arch is not used in system headers or kernel
exports).
To bring objtool to this state the following things are done:
1. current top level tools/objtool/ headers are moved into
include/objtool/ subdirectory,
2. arch specific headers, currently only arch/x86/include/ are moved into
arch/x86/include/arch/ and were stripped of "arch_" suffix,
3. new -I$(srctree)/tools/objtool/include include path to make
includes like <objtool/warn.h> possible,
4. rewriting file includes,
5. make git not to ignore include/objtool/ subdirectory.
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
