06 Dec, 2016
1 commit
-
For the "lea %(rsp), %rbp" case, we check if there is a rex_prefix.
But we check 'bytes' which is insn_byte_t[4] in rex_prefix (insn_field
structure). Therefore, the check is always true.Instead, check 'nbytes' which is the right one.
Signed-off-by: Jiri Slaby
Acked-by: Josh Poimboeuf
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/20161205105551.25917-1-jslaby@suse.cz
Signed-off-by: Ingo Molnar
27 Oct, 2016
1 commit
-
The following commit:
3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
... improved objtool's ability to detect GCC switch statement jump
tables for GCC 6. However the check to allow short jumps with the
scanned range of instructions wasn't quite right. The pattern detection
should allow jumps to the indirect jump instruction itself.This fixes the following warning:
drivers/infiniband/sw/rxe/rxe_comp.o: warning: objtool: rxe_completer()+0x315: sibling call from callable instruction with changed frame pointer
Reported-by: Arnd Bergmann
Signed-off-by: Josh Poimboeuf
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Fixes: 3732710ff6f2 ("objtool: Improve rare switch jump table pattern detection")
Link: http://lkml.kernel.org/r/20161026153408.2rifnw7bvoc5sex7@treble
Signed-off-by: Ingo Molnar
16 Oct, 2016
2 commits
-
Recently objtool has started reporting a few "unreachable instruction"
warnings when CONFIG_GCOV is enabled for newer versions of GCC. Usually
this warning means there's some new control flow that objtool doesn't
understand. But in this case, objtool is correct and the instructions
really are inaccessible. It's an annoying quirk of gcov, but it's
harmless, so it's ok to just silence the warnings.With older versions of GCC, it was relatively easy to detect
gcov-specific instructions and to skip any unreachable warnings produced
by them. But GCC 6 has gotten craftier.Instead of continuing to play whack-a-mole with gcov, just use a bigger,
more permanent hammer and disable unreachable warnings for the whole
file when gcov is enabled. This is fine to do because a) unreachable
warnings are usually of questionable value; and b) gcov isn't used for
production kernels and we can relax the checks a bit there.Reported-by: kbuild test robot
Signed-off-by: Josh Poimboeuf
Cc: Andy Lutomirski
Cc: Arnd Bergmann
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/38d5c87d61d9cd46486dd2c86f46603dff0df86f.1476393584.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
GCC 6 added a new switch statement jump table optimization which makes
objtool's life harder. It looks like:mov [rodata addr],%reg1
... some instructions ...
jmpq *(%reg1,%reg2,8)The optimization is quite rare, but objtool still needs to be able to
identify the pattern so that it can follow all possible control flow
paths related to the switch statement.In order to detect the pattern, objtool starts from the indirect jump
and scans backwards through the function until it finds the first
instruction in the pattern. If it encounters an unconditional jump
along the way, it stops and considers the pattern to be not found.As it turns out, unconditional jumps can happen, as long as they are
small forward jumps within the range being scanned.This fixes the following warnings:
drivers/infiniband/sw/rxe/rxe_comp.o: warning: objtool: rxe_completer()+0x2f4: sibling call from callable instruction with changed frame pointer
drivers/infiniband/sw/rxe/rxe_resp.o: warning: objtool: rxe_responder()+0x10f: sibling call from callable instruction with changed frame pointerReported-by: Arnd Bergmann
Signed-off-by: Josh Poimboeuf
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/8a9ed68ae1780e8d3963e4ee13f2f257fe3a3c33.1476393584.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar
11 Oct, 2016
1 commit
-
Arnd reported that enabling CONFIG_MATOM results in a bunch of objtool
false positive frame pointer warnings:arch/x86/events/intel/ds.o: warning: objtool: intel_pmu_pebs_del()+0x43: call without frame pointer save/setup
security/keys/keyring.o: warning: objtool: keyring_read()+0x59: call without frame pointer save/setup
kernel/signal.o: warning: objtool: __dequeue_signal()+0xd8: call without frame pointer save/setup
...objtool gets confused by the fact that the '-mtune=atom' GCC option
sometimes uses 'lea (%rsp),%rbp' instead of 'mov %rsp,%rbp'. The
instructions are effectively the same, but objtool doesn't know about
the 'lea' variant.Fix the false warnings by adding support for 'lea (%rsp),%rbp' in the
objtool decoder.Reported-by: Arnd Bergmann
Signed-off-by: Josh Poimboeuf
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar
23 Sep, 2016
1 commit
-
objtool reports the following new warning:
kernel/exit.o: warning: objtool: do_exit() falls through to next function complete_and_exit()
The warning is caused by do_exit()'s new call to do_task_dead(), which
is a new "noreturn" function which objtool doesn't know about yet,
introduced by:9af6528ee9b6 ("sched/core: Optimize __schedule()")
( objtool has to know all the global noreturn functions so it can follow
the control flow of any functions which call them. Unfortunately they
need to be hard-coded because there's no automated way to detect them. )Reported-by: kbuild test robot
Signed-off-by: Josh Poimboeuf
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: kbuild-all@01.org
Cc: tipbuild@zytor.com
Link: http://lkml.kernel.org/r/20160922212125.zbuewckqll4yur25@treble
Signed-off-by: Ingo Molnar
31 Jul, 2016
1 commit
-
Pull misc fixes from Thomas Gleixner:
"This update contains:- a fix for stomp-machine so the nmi_watchdog wont trigger on the cpu
waiting for the others to execute the callback- various fixes and updates to objtool including an resync of the
instruction decoder to match the kernel's decoder"* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Un-capitalize "Warning" for out-of-sync instruction decoder
objtool: Resync x86 instruction decoder with the kernel's
objtool: Support new GCC 6 switch jump table pattern
stop_machine: Touch_nmi_watchdog() after MULTI_STOP_PREPARE
objtool: Add 'fixdep' to objtool/.gitignore
29 Jul, 2016
4 commits
-
Change "Warning" to "warning" to make it look more like a GCC warning.
Hopefully that will be enough to help the 0-day bot or other automated
tools catch this warning earlier before it ends up in Linus's tree.Reported-by: Linus Torvalds
Signed-off-by: Josh Poimboeuf
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/b1669f391a5db91040427fd9f8e1e79db18f9709.1469751119.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
This fixes the following warning:
Warning: objtool: x86 instruction decoder differs from kernel
Unfortunately we have three identical copies of the x86 instruction
decoder in the kernel tree that have to be manually kept in sync.It's on my TODO list to at least library-ize the ones in the tools
subdir so we'd only have two of them instead of three. In the meantime,
here's another manual sync.Reported-by: Linus Torvalds
Signed-off-by: Josh Poimboeuf
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Fixes: c61f4d5ebaf0 ("perf tools: Add AVX-512 support to the instruction decoder used by Intel PT")
Link: http://lkml.kernel.org/r/d7f74b4d91fed25b0be33cd5c86f5131fa1a7529.1469751119.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
This fixes some false positive objtool warnings seen with gcc 6.1.1:
kernel/trace/ring_buffer.o: warning: objtool: ring_buffer_read_page()+0x36c: sibling call from callable instruction with changed frame pointer
arch/x86/kernel/reboot.o: warning: objtool: native_machine_emergency_restart()+0x139: sibling call from callable instruction with changed frame pointer
lib/xz/xz_dec_stream.o: warning: objtool: xz_dec_run()+0xc2: sibling call from callable instruction with changed frame pointerWith GCC 6, a new code pattern is sometimes used to access a switch
statement jump table in .rodata, which objtool doesn't yet recognize:mov [rodata addr],%reg1
... some instructions ...
jmpq *(%reg1,%reg2,8)Add support for detecting that pattern. The detection code is rather
crude, but it's still effective at weeding out false positives and
catching real warnings. It can be refined later once objtool starts
reading DWARF CFI.Reported-by: Linus Torvalds
Signed-off-by: Josh Poimboeuf
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/b8c9503b4ad8c8a827cc5400db4c1b40a3ea07bc.1469751119.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
Pull libnvdimm updates from Dan Williams:
- Replace pcommit with ADR / directed-flushing.
The pcommit instruction, which has not shipped on any product, is
deprecated. Instead, the requirement is that platforms implement
either ADR, or provide one or more flush addresses per nvdimm.ADR (Asynchronous DRAM Refresh) flushes data in posted write buffers
to the memory controller on a power-fail event.Flush addresses are defined in ACPI 6.x as an NVDIMM Firmware
Interface Table (NFIT) sub-structure: "Flush Hint Address Structure".
A flush hint is an mmio address that when written and fenced assures
that all previous posted writes targeting a given dimm have been
flushed to media.- On-demand ARS (address range scrub).
Linux uses the results of the ACPI ARS commands to track bad blocks
in pmem devices. When latent errors are detected we re-scrub the
media to refresh the bad block list, userspace can also request a
re-scrub at any time.- Support for the Microsoft DSM (device specific method) command
format.- Support for EDK2/OVMF virtual disk device memory ranges.
- Various fixes and cleanups across the subsystem.
* tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (41 commits)
libnvdimm-btt: Delete an unnecessary check before the function call "__nd_device_register"
nfit: do an ARS scrub on hitting a latent media error
nfit: move to nfit/ sub-directory
nfit, libnvdimm: allow an ARS scrub to be triggered on demand
libnvdimm: register nvdimm_bus devices with an nd_bus driver
pmem: clarify a debug print in pmem_clear_poison
x86/insn: remove pcommit
Revert "KVM: x86: add pcommit support"
nfit, tools/testing/nvdimm/: unify shutdown paths
libnvdimm: move ->module to struct nvdimm_bus_descriptor
nfit: cleanup acpi_nfit_init calling convention
nfit: fix _FIT evaluation memory leak + use after free
tools/testing/nvdimm: add manufacturing_{date|location} dimm properties
tools/testing/nvdimm: add virtual ramdisk range
acpi, nfit: treat virtual ramdisk SPA as pmem region
pmem: kill __pmem address space
pmem: kill wmb_pmem()
libnvdimm, pmem: use nvdimm_flush() for namespace I/O writes
fs/dax: remove wmb_pmem()
libnvdimm, pmem: flush posted-write queues on shutdown
...
27 Jul, 2016
2 commits
-
To fix:
Untracked files:
(use "git add ..." to include in what will be committed)tools/objtool/fixdep
Signed-off-by: Paul Gortmaker
Signed-off-by: Josh Poimboeuf
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/a4571f6893caf737d05524cfa3829c2abc1fb240.1469452729.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
Pull perf fixes from Ingo Molnar:
"This tree contains tooling fixes plus some additions:- fixes to the vdso2c build environment that Stephen Rothwell is
using for the linux-next build (Arnaldo Carvalho de Melo)- AVX-512 instruction mappings (Adrian Hunter)
- misc fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "perf tools: event.h needs asm/perf_regs.h"
x86: Make the vdso2c compiler use the host architecture headers
tools build: Fix objtool build with ARCH=x86_64
objtool: Always use host headers
objtool: Use tools/scripts/Makefile.arch to get ARCH and HOSTARCH
tools build: Add HOSTARCH Makefile variable
perf tests kmod-path: Fix build on ubuntu:16.04-x-armhf
perf tools: Add AVX-512 instructions to the new instructions test
perf tools: Add AVX-512 support to the instruction decoder used by Intel PT
x86/insn: Add AVX-512 support to the instruction decoder
x86/insn: perf tools: Fix vcvtph2ps instruction decoding
26 Jul, 2016
1 commit
-
Pull perf updates from Ingo Molnar:
"With over 300 commits it's been a busy cycle - with most of the work
concentrated on the tooling side (as it should).The main kernel side enhancements were:
- Add per event callchain limit: Recently we introduced a sysctl to
tune the max-stack for all events for which callchains were
requested:$ sysctl kernel.perf_event_max_stack
kernel.perf_event_max_stack = 127Now this patch introduces a way to configure this per event, i.e.
this becomes possible:$ perf record -e sched:*/max-stack=2/ -e block:*/max-stack=10/ -a
allowing finer tuning of how much buffer space callchains use.
This uses an u16 from the reserved space at the end, leaving
another u16 for future use.There has been interest in even finer tuning, namely to control the
max stack for kernel and userspace callchains separately. Further
discussion is needed, we may for instance use the remaining u16 for
that and when it is present, assume that the sample_max_stack
introduced in this patch applies for the kernel, and the u16 left
is used for limiting the userspace callchain (Arnaldo Carvalho de
Melo)- Optimize AUX event (hardware assisted side-band event) delivery
(Kan Liang)- Rework Intel family name macro usage (this is partially x86 arch
work) (Dave Hansen)- Refine and fix Intel LBR support (David Carrillo-Cisneros)
- Add support for Intel 'TopDown' events (Andi Kleen)
- Intel uncore PMU driver fixes and enhancements (Kan Liang)
- ... other misc changes.
Here's an incomplete list of the tooling enhancements (but there's
much more, see the shortlog and the git log for details):- Support cross unwinding, i.e. collecting '--call-graph dwarf'
perf.data files in one machine and then doing analysis in another
machine of a different hardware architecture. This enables, for
instance, to do:$ perf record -a --call-graph dwarf
on a x86-32 or aarch64 system and then do 'perf report' on it on a
x86_64 workstation (He Kuang)- Allow reading from a backward ring buffer (one setup via
sys_perf_event_open() with perf_event_attr.write_backward = 1)
(Wang Nan)- Finish merging initial SDT (Statically Defined Traces) support, see
cset comments for details about how it all works (Masami Hiramatsu)- Support attaching eBPF programs to tracepoints (Wang Nan)
- Add demangling of symbols in programs written in the Rust language
(David Tolnay)- Add support for tracepoints in the python binding, including an
example, that sets up and parses sched:sched_switch events,
tools/perf/python/tracepoint.py (Jiri Olsa)- Introduce --stdio-color to set up the color output mode selection
in 'annotate' and 'report', allowing emit color escape sequences
when redirecting the output of these tools (Arnaldo Carvalho de
Melo)- Add 'callindent' option to 'perf script -F', to indent the Intel PT
call stack, making this output more ftrace-like (Adrian Hunter,
Andi Kleen)- Allow dumping the object files generated by llvm when processing
eBPF scriptlet events (Wang Nan)- Add stackcollapse.py script to help generating flame graphs (Paolo
Bonzini)- Add --ldlat option to 'perf mem' to specify load latency for loads
event (e.g. cpu/mem-loads/ ) (Jiri Olsa)- Tooling support for Intel TopDown counters, recently added to the
kernel (Andi Kleen)"* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (303 commits)
perf tests: Add is_printable_array test
perf tools: Make is_printable_array global
perf script python: Fix string vs byte array resolving
perf probe: Warn unmatched function filter correctly
perf cpu_map: Add more helpers
perf stat: Balance opening and reading events
tools: Copy linux/{hash,poison}.h and check for drift
perf tools: Remove include/linux/list.h from perf's MANIFEST
tools: Copy the bitops files accessed from the kernel and check for drift
Remove: kernel unistd*h files from perf's MANIFEST, not used
perf tools: Remove tools/perf/util/include/linux/const.h
perf tools: Remove tools/perf/util/include/asm/byteorder.h
perf tools: Add missing linux/compiler.h include to perf-sys.h
perf jit: Remove some no-op error handling
perf jit: Add missing curly braces
objtool: Initialize variable to silence old compiler
objtool: Add -I$(srctree)/tools/arch/$(ARCH)/include/uapi
perf record: Add --tail-synthesize option
perf session: Don't warn about out of order event if write_backward is used
perf tools: Enable overwrite settings
...
24 Jul, 2016
1 commit
-
The pcommit instruction is being deprecated in favor of either ADR
(asynchronous DRAM refresh: flush-on-power-fail) at the platform level, or
posted-write-queue flush addresses as defined by the ACPI 6.x NFIT (NVDIMM
Firmware Interface Table).Cc: Thomas Gleixner
Cc: "H. Peter Anvin"
Cc: x86@kernel.org
Cc: Josh Poimboeuf
Cc: Peter Zijlstra
Cc: Arnaldo Carvalho de Melo
Cc: Alexander Shishkin
Cc: Borislav Petkov
Cc: Andy Lutomirski
Cc: Xiao Guangrong
Cc: Adrian Hunter
Cc: Ross Zwisler
Acked-by: Ingo Molnar
Signed-off-by: Dan Williams
23 Jul, 2016
3 commits
-
The objtool build fails in a cross-compiled environment on a non-x86
host with "ARCH=x86_64":tools/objtool/objtool-in.o: In function `decode_instructions':
tools/objtool/builtin-check.c:276: undefined reference to `arch_decode_instruction'We could override the ARCH environment variable and change it back to
x86, similar to what the objtool Makefile was doing before; but it's
tricky to override environment variables consistently.Instead, take a similar approach used by the Linux top-level Makefile
and introduce a SRCARCH Makefile variable which evaluates to "x86" when
ARCH is either "x86_64" or "x86".Reported-by: Stephen Rothwell
Signed-off-by: Josh Poimboeuf
Cc: Andy Lutomirski
Cc: H. Peter Anvin
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/20160722191920.ej62fnspnqurbaa7@treble
Signed-off-by: Arnaldo Carvalho de Melo -
From a conversation with Josh:
From http://lkml.kernel.org/r/20160722034118.guckaniobf3f7czc@treble :
It needs to be compiled with the host (powerpc) compiler, but then it
needs to disassemble target (x86) files.----
So use HOSTARCH instead of ARCH.
Cc: Adrian Hunter
Cc: David Ahern
Cc: Jiri Olsa
Cc: Josh Poimboeuf
Cc: Namhyung Kim
Cc: Stephen Rothwell
Cc: Wang Nan
Link: http://lkml.kernel.org/r/20160722034118.guckaniobf3f7czc@treble
Link: http://lkml.kernel.org/n/tip-le1m1yzxnfpt3msbblu40nm8@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo -
objtool's Makefile was setting up ARCH but fixing up just the x86_64 ->
x86, using Makefile.arch will do the necessary fixups for all arches.Cc: Adrian Hunter
Cc: David Ahern
Cc: Jiri Olsa
Cc: Josh Poimboeuf
Cc: Namhyung Kim
Cc: Stephen Rothwell
Cc: Wang Nan
Link: http://lkml.kernel.org/n/tip-hbq0bbh03u2b722vozcyql31@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo
16 Jul, 2016
2 commits
-
gcc version 4.1.2 20080704 (Red Hat 4.1.2-55) barfs with:
CC /tmp/build/objtool/builtin-check.o
cc1: warnings being treated as errors
builtin-check.c: In function 'cmd_check':
builtin-check.c:667: warning: 'prev_rela' may be used uninitialized in this function
mv: cannot stat `/tmp/build/objtool/.builtin-check.o.tmp': No such file or directory
make[1]: *** [/tmp/build/objtool/builtin-check.o] Error 1Init it to NULL to silence it.
Cc: Adrian Hunter
Cc: David Ahern
Cc: Jiri Olsa
Cc: Josh Poimboeuf
Cc: Namhyung Kim
Cc: Wang Nan
Link: http://lkml.kernel.org/n/tip-qolo31rl2ojlwj1lj9dhemyz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo -
So that it can find asm/bitsperlong.h to get the __BITS_PER_LONG
definition.Cc: Adrian Hunter
Cc: David Ahern
Cc: Jiri Olsa
Cc: Josh Poimboeuf
Cc: Namhyung Kim
Cc: Peter Zijlstra
Cc: Wang Nan
Link: http://lkml.kernel.org/n/tip-pr3pvskh65pey4po7t122z4j@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo
14 Jul, 2016
2 commits
-
That doesn't have -I to match lines.
Cc: Adrian Hunter
Cc: David Ahern
Cc: Jiri Olsa
Cc: Josh Poimboeuf
Cc: Namhyung Kim
Cc: Wang Nan
Link: http://lkml.kernel.org/n/tip-1zqv1h6okt70e2huokkdtf1u@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo -
Not all libelf implementations have this "Please, ELF_C_READ, but use
mmap if possible" elf_begin() cmd, so provide a fallback to plain old
ELF_C_READ.Case in point: Alpine Linux 3.4.
Cc: Adrian Hunter
Cc: David Ahern
Cc: Jiri Olsa
Cc: Josh Poimboeuf
Cc: Namhyung Kim
Cc: Wang Nan
Link: http://lkml.kernel.org/n/tip-1fctuknrawgoi5xqon4mu9dv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo
13 Jul, 2016
2 commits
-
To make it portable to non-glibc systems, that follow the XSI variant
instead of the GNU specific one that gets in place when _GNU_SOURCE is
defined.Cc: Adrian Hunter
Cc: David Ahern
Cc: Jiri Olsa
Cc: Josh Poimboeuf
Cc: Namhyung Kim
Cc: Steven Rostedt
Cc: Wang Nan
Link: http://lkml.kernel.org/n/tip-bozcszy93tpgw9ad6qm3dhpx@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo -
They were in tools/include/linux/kernel.h, requiring that it in turn
included stdio.h, which is way too heavy.Cc: Adrian Hunter
Cc: David Ahern
Cc: Jiri Olsa
Cc: Josh Poimboeuf
Cc: Namhyung Kim
Cc: Wang Nan
Link: http://lkml.kernel.org/n/tip-855h8olnkot9v0dajuee1lo3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo
10 Jul, 2016
1 commit
-
Mathieu Desnoyers reported that the STACK_FRAME_NON_STANDARD macro
wasn't working with the lttng_filter_interpret_bytecode() function in
the lttng-modules code.Usually the relocation created by STACK_FRAME_NON_STANDARD creates a
reference to a section symbol like this:Offset Type Value Addend Name
000000000000000000 X86_64_64 000000000000000000 +3136 .textBut in this case it created a reference to a function symbol:
Offset Type Value Addend Name
000000000000000000 X86_64_64 0x00000000000003a0 +0 lttng_filter_interpret_bytecodeTo be honest I have no idea what causes gcc to decide to do one over the
other. But both are valid ELF, so add support for the function symbol.Reported-by: Mathieu Desnoyers
Signed-off-by: Josh Poimboeuf
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: lttng-dev@lists.lttng.org
Link: http://lkml.kernel.org/r/9cee42843bc6d94e990a152e4e0319cfdf6756ef.1466023450.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar
17 May, 2016
1 commit
-
The switch to elf_getshdr{num,strndx} post-dates the oldest tool chain
the kernel is supposed to be able to build with, so try to cope with
such an environment.Signed-off-by: Jan Beulich
Signed-off-by: Josh Poimboeuf
Cc: # for v4.6
Cc: Alexander Shishkin
Cc: Arnaldo Carvalho de Melo
Cc: Jan Beulich
Cc: Jiri Olsa
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Stephane Eranian
Cc: Thomas Gleixner
Cc: Vince Weaver
Link: http://lkml.kernel.org/r/732dae6872b7ff187d94f22bb699a12849d3fe04.1463430618.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar
16 Apr, 2016
1 commit
-
There are several cases in compiled C code where a function may not
return at the end, and may instead fall through to the next function.That may indicate a bug in the code, or a gcc bug, or even an objtool
bug. But in each case, objtool reports an unhelpful warning, something
like:drivers/scsi/qla2xxx/qla_attr.o: warning: objtool: qla2x00_get_fc_host_stats()+0x0: duplicate frame pointer save
drivers/scsi/qla2xxx/qla_attr.o: warning: objtool: qla2x00_get_fc_host_stats()+0x0: frame pointer state mismatchDetect this situation and print a more useful error message:
drivers/scsi/qla2xxx/qla_attr.o: warning: objtool: qla2x00_get_host_fabric_name() falls through to next function qla2x00_get_starget_node_name()
Also add some information about this warning and its potential causes to
the documentation.Reported-by: kbuild test robot
Signed-off-by: Josh Poimboeuf
Cc: Alexander Shishkin
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: H. Peter Anvin
Cc: Jiri Olsa
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/caa4ec6c687931db805e692d4e4bf06cd87d33e6.1460729697.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar
15 Apr, 2016
1 commit
-
GCC has a rare quirk, currently only seen in three driver functions in
the kernel, and only with certain obscure non-distro configs, which can
cause objtool to produce "unreachable instruction" false positive
warnings.As part of an optimization, GCC makes a copy of an existing switch jump
table, modifies it, and then hard-codes the jump (albeit with an
indirect jump) to use a single entry in the table. The rest of the jump
table and some of its jump targets remain as dead code.In such a case we can just crudely ignore all unreachable instruction
warnings for the entire object file. Ideally we would just ignore them
for the function, but that would require redesigning the code quite a
bit. And honestly that's just not worth doing: unreachable instruction
warnings are of questionable value anyway, and this is a very rare
issue.kbuild reports:
https://lkml.kernel.org/r/201603231906.LWcVUpxm%25fengguang.wu@intel.com
https://lkml.kernel.org/r/201603271114.K9i45biy%25fengguang.wu@intel.com
https://lkml.kernel.org/r/201603291058.zuJ6ben1%25fengguang.wu@intel.comGCC bug:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70604
Reported-by: kbuild test robot
Signed-off-by: Josh Poimboeuf
Cc: Linus Torvalds
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/700fa029bbb0feff34f03ffc69d666a3c3b57a61.1460663532.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar
09 Mar, 2016
10 commits
-
When objtool discovers an issue, it's very common for it to flood the
terminal with a lot of duplicate warnings. For example:warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch
warning: objtool: rtlwifi_rate_mapping()+0x2f3: frame pointer state mismatch
warning: objtool: rtlwifi_rate_mapping()+0x2ff: frame pointer state mismatch
warning: objtool: rtlwifi_rate_mapping()+0x30b: frame pointer state mismatch
...The first warning is usually all you need. Change it to only warn once
per function.Suggested-by: Ingo Molnar
Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/c47f3ca38aa01e2a9b6601f9e38efd414c3f3c18.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
Use hash tables for instruction and rela lookups (and keep the linked
lists around for sequential access).Also cache the section struct for the "__func_stack_frame_non_standard"
section.With this change, "objtool check net/wireless/nl80211.o" goes from:
real 0m1.168s
user 0m1.163s
sys 0m0.005sto:
real 0m0.059s
user 0m0.042s
sys 0m0.017sfor a 20x speedup.
With the same object, it should be noted that the memory heap usage grew
from 8MB to 62MB. Reducing the memory usage is on the TODO list.Reported-by: Ingo Molnar
Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/dd0d8e1449506cfa7701b4e7ba73577077c44253.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
Ingo reported [1] some false positive objtool warnings:
drivers/net/wireless/realtek/rtlwifi/base.o: warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch
drivers/net/wireless/realtek/rtlwifi/base.o: warning: objtool: rtlwifi_rate_mapping()+0x2f3: frame pointer state mismatch
...And so did the 0-day bot [2]:
drivers/gpu/drm/radeon/cik.o: warning: objtool: cik_tiling_mode_table_init()+0x6ce: call without frame pointer save/setup
drivers/gpu/drm/radeon/cik.o: warning: objtool: cik_tiling_mode_table_init()+0x72b: call without frame pointer save/setup
...Both sets of warnings involve functions which have multiple switch
statements. When there's more than one switch statement in a function,
objtool interprets all the switch jump tables as a single table. If the
targets of one jump table assume a stack frame and the targets of
another one don't, it prints false positive warnings.Fix the bug by detecting the size of each switch jump table. For
multiple tables, each one ends where the next one begins.[1] https://lkml.kernel.org/r/20160308103716.GA9618@gmail.com
[2] https://lists.01.org/pipermail/kbuild-all/2016-March/018124.htmlReported-by: Ingo Molnar
Reported-by: kbuild test robot
Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/2d7eecc6bc52d301f494b80f5fd62c2b6c895658.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
Rename some list heads to distinguish them from hash node heads, which
are added later in the patch series.Also rename the get_*() functions to add_*(), which is more descriptive:
they "add" data to the objtool_file struct.Also rename rodata_rela and text_rela to be clearer:
- text_rela refers to a rela entry in .rela.text.
- rodata_rela refers to a rela entry in .rela.rodata.Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/ee0eca2bba8482aa45758958c5586c00a7b71e62.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
The insns list is initialized twice, in cmd_check() and in
decode_instructions(). Remove the latter.Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/be6e21d7eec1f072095d22a1cbe144057135e097.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
Add some helper macros to make it easier to traverse instructions, and
to abstract the details of the instruction list implementation in
preparation for creating a hash structure.Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/8e1715d5035bc02b4db28d0fccef6bb1170d1f12.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
With some configs [1], objtool prints a bunch of false positive warnings
like:arch/x86/events/core.o: warning: objtool: x86_del_exclusive()+0x0: frame pointer state mismatch
For some reason this config has a bunch of sibling calls. When objtool
follows a sibling call jump, it attempts to compare the frame pointer
state. But it also accidentally compares the FENTRY state, resulting in
a false positive warning.[1] https://lkml.kernel.org/r/20160308154909.GA20956@gmail.com
Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/382de77ccaaa8cd79b27a155c3d109ebd4ce0219.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
Compile objtool with debugging symbols ('-g') to help tools like perf
and gdb understand what it's doing. Combined with '-O2', it's not
always helpful, but it's better than nothing.Reported-by: Ingo Molnar
Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/c295e9ee9ed360dc8b2e1d180c859f11cfc151ef.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
I don't _think_ dead_end_function() can get into a recursive loop, but
just in case, stop the loop and print a warning.Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/ff489a63e6feb88abb192cfb361d81626dcf3e89.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
Ingo reported an infinite loop in objtool with a certain randconfig [1].
With the given config, two functions in crypto/ablkcipher.o contained
sibling calls to each other, which threw the recursive call in
dead_end_function() for a loop (literally!).Split the noreturn detection into two passes. In the first pass, check
for return instructions. In the second pass, do the potentially
recursive sibling call check. In most cases, the first pass will be
good enough. In the rare case where a second pass is needed, recursion
should hopefully no longer be possible.[1] https://lkml.kernel.org/r/20160308154909.GA20956@gmail.com
Reported-by: Ingo Molnar
Signed-off-by: Josh Poimboeuf
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Arnaldo Carvalho de Melo
Cc: Arnaldo Carvalho de Melo
Cc: Bernd Petrovitsch
Cc: Borislav Petkov
Cc: Chris J Arges
Cc: Jiri Slaby
Cc: Linus Torvalds
Cc: Michal Marek
Cc: Namhyung Kim
Cc: Pedro Alves
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/16afb602640ef43b7782087d6cca17bf6fc13603.1457502970.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar
03 Mar, 2016
2 commits
-
When building with CONFIG_STACK_VALIDATION on a ppc64le host with an x86
cross-compiler, Stephen Rothwell saw the following objtool build errors:DESCEND objtool
CC /home/sfr/next/x86_64_allmodconfig/tools/objtool/builtin-check.o
CC /home/sfr/next/x86_64_allmodconfig/tools/objtool/special.o
CC /home/sfr/next/x86_64_allmodconfig/tools/objtool/elf.o
CC /home/sfr/next/x86_64_allmodconfig/tools/objtool/objtool.o
MKDIR /home/sfr/next/x86_64_allmodconfig/tools/objtool/arch/x86/insn/
CC /home/sfr/next/x86_64_allmodconfig/tools/objtool/libstring.o
elf.c:22:23: fatal error: sys/types.h: No such file or directory
compilation terminated.
CC /home/sfr/next/x86_64_allmodconfig/tools/objtool/exec-cmd.o
CC /home/sfr/next/x86_64_allmodconfig/tools/objtool/help.o
builtin-check.c:28:20: fatal error: string.h: No such file or directory
compilation terminated.
objtool.c:28:19: fatal error: stdio.h: No such file or directory
compilation terminated.It fails to build because it tries to compile objtool with the
cross-compiler instead of the host compiler.Ensure that it always uses the host compiler by ignoring CROSS_COMPILE.
In order to do that properly, the libsubcmd.a library needs to be built
in tools/objtool/ rather than tools/lib/subcmd/. The latter directory
contains the cross-compiled version which is needed for perf and
possibly other tools.Note that cross-compiling for x86 on a _big_ endian system would result
in a bunch of false positive objtool warnings during the kernel build
because it isn't endian-aware. But that's generally a rare edge case
and there haven't been any reports of anybody needing that.Reported-by: Stephen Rothwell
Signed-off-by: Josh Poimboeuf
Cc: Adrian Hunter
Cc: Linus Torvalds
Cc: Masami Hiramatsu
Cc: Michael Ellerman
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/55b63eefc347f1bb28573f972d8d1adbf1f1c31d.1456962210.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar -
When running objtool on a ppc64le host to analyze x86 binaries, it
reports a lot of false warnings like:ipc/compat_mq.o: warning: objtool: compat_SyS_mq_open()+0x91: can't find jump dest instruction at .text+0x3a5
The warnings are caused by the x86 instruction decoder setting the wrong
value for the jump instruction's immediate field because it assumes that
"char == signed char", which isn't true for all architectures. When
converting char to int, gcc sign-extends on x86 but doesn't sign-extend
on ppc64le.According to the gcc man page, that's a feature, not a bug:
> Each kind of machine has a default for what "char" should be. It is
> either like "unsigned char" by default or like "signed char" by
> default.
>
> Ideally, a portable program should always use "signed char" or
> "unsigned char" when it depends on the signedness of an object.Conform to the "standards" by changing the "char" casts to "signed
char". This results in no actual changes to the object code on x86.Note: the x86 decoder now lives in three different locations in the
kernel tree, which are all kept in sync via makefile checks and
warnings: in-kernel, perf, and objtool. This fixes all three locations.
Eventually we should probably try to at least converge the two separate
"tools" locations into a single shared location.Signed-off-by: Josh Poimboeuf
Cc: Adrian Hunter
Cc: Linus Torvalds
Cc: Masami Hiramatsu
Cc: Michael Ellerman
Cc: Peter Zijlstra
Cc: Stephen Rothwell
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/9dd4161719b20e6def9564646d68bfbe498c549f.1456962210.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar