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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2017-07-07 09:19:42 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-07-08 10:29:48 +0200 |
| commit | 4855022a52262411ce38c93dec4cb1470705c0a0 (patch) | |
| tree | dbeb97d79e64df1492aae5b792c2b27139f696db /tools/objtool | |
| parent | 4422d80ed7d4bdb2d6e9fb890c66c3d9250ba694 (diff) | |
| download | linux-4855022a52262411ce38c93dec4cb1470705c0a0.tar.bz2 | |
objtool: Fix sibling call detection logic
With some configs, objtool reports the following warning:
arch/x86/kernel/ftrace.o: warning: objtool: ftrace_modify_code_direct()+0x2d: sibling call from callable instruction with modified stack frame
The instruction it's complaining about isn't actually a sibling call.
It's just a normal jump to an address inside the function. Objtool
thought it was a sibling call because the instruction's jump_dest wasn't
initialized because the function was supposed to be ignored due to its
use of sync_core().
Objtool ended up validating the function instead of ignoring it because
it didn't properly recognize a sibling call to the function. So fix the
sibling call logic. Also add a warning to catch ignored functions being
validated so we'll get a more useful error message next time.
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/96cc8ecbcdd8cb29ddd783817b4af918a6a171b0.1499437107.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/objtool')
| -rw-r--r-- | tools/objtool/check.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index fea222192c57..2c6d74880403 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1371,6 +1371,12 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, func = insn->func; + if (func && insn->ignore) { + WARN_FUNC("BUG: why am I validating an ignored function?", + sec, insn->offset); + return -1; + } + if (insn->visited) { if (!!insn_state_match(insn, &state)) return 1; @@ -1426,16 +1432,19 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, case INSN_JUMP_CONDITIONAL: case INSN_JUMP_UNCONDITIONAL: - if (insn->jump_dest) { + if (insn->jump_dest && + (!func || !insn->jump_dest->func || + func == insn->jump_dest->func)) { ret = validate_branch(file, insn->jump_dest, state); if (ret) return 1; + } else if (func && has_modified_stack_frame(&state)) { WARN_FUNC("sibling call from callable instruction with modified stack frame", sec, insn->offset); return 1; - } /* else it's a sibling call */ + } if (insn->type == INSN_JUMP_UNCONDITIONAL) return 0; |