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authorJosh Poimboeuf <jpoimboe@redhat.com>2020-09-10 10:24:57 -0500
committerBorislav Petkov <bp@suse.de>2020-09-18 19:37:51 +0200
commitdb6c6a0df840e3f52c84cc302cc1a08ba11a4416 (patch)
tree9eae3f90a763b5b8c551a1d46f5b11c7bedacbe5 /tools/objtool
parent856deb866d16e29bd65952e0289066f6078af773 (diff)
objtool: Fix noreturn detection for ignored functions
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 <torvalds@linux-foundation.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/5b1e2536cdbaa5246b60d7791b76130a74082c62.1599751464.git.jpoimboe@redhat.com
Diffstat (limited to 'tools/objtool')
-rw-r--r--tools/objtool/check.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index e034a8f24f46..90a66891441a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -619,7 +619,7 @@ static int add_jump_destinations(struct objtool_file *file)
if (!is_static_jump(insn))
continue;
- if (insn->ignore || insn->offset == FAKE_JUMP_OFFSET)
+ if (insn->offset == FAKE_JUMP_OFFSET)
continue;
reloc = find_reloc_by_dest_range(file->elf, insn->sec,