kernel/linux.git/tools/objtool/check.c, branch v5.4.232

objtool: Add a missing comma to avoid string concatenation

2023-02-06T06:52:49+00:00

commit 1fb466dff904e4a72282af336f2c355f011eec61 upstream. Recently the kbuild robot reported two new errors: >> lib/kunit/kunit-example-test.o: warning: objtool: .text.unlikely: unexpected end of section >> arch/x86/kernel/dumpstack.o: warning: objtool: oops_end() falls through to next function show_opcodes() I don't know why they did not occur in my test setup but after digging it I realized I had accidentally dropped a comma in tools/objtool/check.c when I renamed rewind_stack_do_exit to rewind_stack_and_make_dead. Add that comma back to fix objtool errors. Link: https://lkml.kernel.org/r/202112140949.Uq5sFKR1-lkp@intel.com Fixes: 0e25498f8cd4 ("exit: Add and use make_task_dead.") Reported-by: kernel test robot Signed-off-by: "Eric W. Biederman" Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

exit: Add and use make_task_dead.

2023-02-06T06:52:49+00:00

commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream. There are two big uses of do_exit. The first is it's design use to be the guts of the exit(2) system call. The second use is to terminate a task after something catastrophic has happened like a NULL pointer in kernel code. Add a function make_task_dead that is initialy exactly the same as do_exit to cover the cases where do_exit is called to handle catastrophic failure. In time this can probably be reduced to just a light wrapper around do_task_dead. For now keep it exactly the same so that there will be no behavioral differences introducing this new concept. Replace all of the uses of do_exit that use it for catastraphic task cleanup with make_task_dead to make it clear what the code is doing. As part of this rename rewind_stack_do_exit rewind_stack_and_make_dead. Signed-off-by: "Eric W. Biederman" Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

objtool: Fix SEGFAULT

2023-01-18T10:41:43+00:00

[ Upstream commit efb11fdb3e1a9f694fa12b70b21e69e55ec59c36 ] find_insn() will return NULL in case of failure. Check insn in order to avoid a kernel Oops for NULL pointer dereference. Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Acked-by: Josh Poimboeuf Acked-by: Peter Zijlstra (Intel) Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-9-sv@linux.ibm.com Signed-off-by: Sasha Levin

x86/xen: Mark cpu_bringup_and_idle() as dead_end_function

2022-05-25T07:14:38+00:00

commit 9af9dcf11bda3e2c0e24c1acaacb8685ad974e93 upstream. The asm_cpu_bringup_and_idle() function is required to push the return value on the stack in order to make ORC happy, but the only reason objtool doesn't complain is because of a happy accident. The thing is that asm_cpu_bringup_and_idle() doesn't return, so validate_branch() never terminates and falls through to the next function, which in the normal case is the hypercall_page. And that, as it happens, is 4095 NOPs and a RET. Make asm_cpu_bringup_and_idle() terminate on it's own, by making the function it calls as a dead-end. This way we no longer rely on what code happens to come after. Fixes: c3881eb58d56 ("x86/xen: Make the secondary CPU idle tasks reliable") Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Juergen Gross Reviewed-by: Miroslav Benes Link: https://lore.kernel.org/r/20210624095147.693801717@infradead.org Signed-off-by: Greg Kroah-Hartman

objtool: Fix ".cold" section suffix check for newer versions of GCC

2021-03-04T09:26:30+00:00

[ Upstream commit 34ca59e109bdf69704c33b8eeffaa4c9f71076e5 ] With my version of GCC 9.3.1 the ".cold" subfunctions no longer have a numbered suffix, so the trailing period is no longer there. Presumably this doesn't yet trigger a user-visible bug since most of the subfunction detection logic is duplicated. I only found it when testing vmlinux.o validation. Fixes: 54262aa28301 ("objtool: Fix sibling call detection") Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/ca0b5a57f08a2fbb48538dd915cc253b5edabb40.1611263461.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin

objtool: Fix error handling for STD/CLD warnings

2021-03-04T09:26:30+00:00

[ Upstream commit 6f567c9300a5ebd7b18c26dda1c8d6ffbdd0debd ] Actually return an error (and display a backtrace, if requested) for directional bit warnings. Fixes: 2f0f9e9ad7b3 ("objtool: Add Direction Flag validation") Signed-off-by: Josh Poimboeuf Link: https://lore.kernel.org/r/dc70f2adbc72f09526f7cab5b6feb8bf7f6c5ad4.1611263461.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin

objtool: Fix noreturn detection for ignored functions

2020-10-01T11:18:15+00:00

[ Upstream commit db6c6a0df840e3f52c84cc302cc1a08ba11a4416 ] When a function is annotated with STACK_FRAME_NON_STANDARD, objtool doesn't validate its code paths. It also skips sibling call detection within the function. But sibling call detection is actually needed for the case where the ignored function doesn't have any return instructions. Otherwise objtool naively marks the function as implicit static noreturn, which affects the reachability of its callers, resulting in "unreachable instruction" warnings. Fix it by just enabling sibling call detection for ignored functions. The 'insn->ignore' check in add_jump_destinations() is no longer needed after e6da9567959e ("objtool: Don't use ignore flag for fake jumps"). Fixes the following warning: arch/x86/kvm/vmx/vmx.o: warning: objtool: vmx_handle_exit_irqoff()+0x142: unreachable instruction which triggers on an allmodconfig with CONFIG_GCOV_KERNEL unset. Reported-by: Linus Torvalds Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Acked-by: Linus Torvalds Link: https://lkml.kernel.org/r/5b1e2536cdbaa5246b60d7791b76130a74082c62.1599751464.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin

objtool: Ignore empty alternatives

2020-06-22T07:30:50+00:00

[ Upstream commit 7170cf47d16f1ba29eca07fd818870b7af0a93a5 ] The .alternatives section can contain entries with no original instructions. Objtool will currently crash when handling such an entry. Just skip that entry, but still give a warning to discourage useless entries. Signed-off-by: Julien Thierry Acked-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

objtool: Fix stack offset tracking for indirect CFAs

2020-05-14T05:58:29+00:00

commit d8dd25a461e4eec7190cb9d66616aceacc5110ad upstream. When the current frame address (CFA) is stored on the stack (i.e., cfa->base == CFI_SP_INDIRECT), objtool neglects to adjust the stack offset when there are subsequent pushes or pops. This results in bad ORC data at the end of the ENTER_IRQ_STACK macro, when it puts the previous stack pointer on the stack and does a subsequent push. This fixes the following unwinder warning: WARNING: can't dereference registers at 00000000f0a6bdba for ip interrupt_entry+0x9f/0xa0 Fixes: 627fce14809b ("objtool: Add ORC unwind table generation") Reported-by: Vince Weaver Reported-by: Dave Jones Reported-by: Steven Rostedt Reported-by: Vegard Nossum Reported-by: Joe Mario Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Jann Horn Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lore.kernel.org/r/853d5d691b29e250333332f09b8e27410b2d9924.1587808742.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman

objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings

2020-05-02T06:48:57+00:00

[ Upstream commit bd841d6154f5f41f8a32d3c1b0bc229e326e640a ] CONFIG_UBSAN_TRAP causes GCC to emit a UD2 whenever it encounters an unreachable code path. This includes __builtin_unreachable(). Because the BUG() macro uses __builtin_unreachable() after it emits its own UD2, this results in a double UD2. In this case objtool rightfully detects that the second UD2 is unreachable: init/main.o: warning: objtool: repair_env_string()+0x1c8: unreachable instruction We weren't able to figure out a way to get rid of the double UD2s, so just silence the warning. Reported-by: Randy Dunlap Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Reviewed-by: Kees Cook Reviewed-by: Miroslav Benes Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/6653ad73c6b59c049211bd7c11ed3809c20ee9f5.1585761021.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin