| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2019-05-13 17:01:32 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-21 16:48:56 (GMT) |
| commit | 15e6da9ae57165505b78d25d2a46df3516171c55 (patch) | |
| tree | 611575f70fc2c1c6528a9268dd4b00c8ef6ea8cc | |
| parent | 2f27bfffb469bd42c8ec07659d846e7e36a0f54c (diff) | |
| download | common-15e6da9ae57165505b78d25d2a46df3516171c55.zip common-15e6da9ae57165505b78d25d2a46df3516171c55.tar.gz common-15e6da9ae57165505b78d25d2a46df3516171c55.tar.bz2 | |
objtool: Fix function fallthrough detection
commit e6f393bc939d566ce3def71232d8013de9aaadde upstream.
When a function falls through to the next function due to a compiler
bug, objtool prints some obscure warnings. For example:
drivers/regulator/core.o: warning: objtool: regulator_count_voltages()+0x95: return with modified stack frame
drivers/regulator/core.o: warning: objtool: regulator_count_voltages()+0x0: stack state mismatch: cfa1=7+32 cfa2=7+8
Instead it should be printing:
drivers/regulator/core.o: warning: objtool: regulator_supply_is_couple() falls through to next function regulator_count_voltages()
This used to work, but was broken by the following commit:
13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
The padding nops at the end of a function aren't actually part of the
function, as defined by the symbol table. So the 'func' variable in
validate_branch() is getting cleared to NULL when a padding nop is
encountered, breaking the fallthrough detection.
If the current instruction doesn't have a function associated with it,
just consider it to be part of the previously detected function by not
overwriting the previous value of 'func'.
Reported-by: kbuild test robot <lkp@intel.com>
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>
Cc: <stable@vger.kernel.org>
Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
Link: http://lkml.kernel.org/r/546d143820cd08a46624ae8440d093dd6c902cae.1557766718.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | tools/objtool/check.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 3ff025b..ae34467 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1779,7 +1779,8 @@ static int validate_branch(struct objtool_file *file, struct instruction *first, return 1; } - func = insn->func ? insn->func->pfunc : NULL; + if (insn->func) + func = insn->func->pfunc; if (func && insn->ignore) { WARN_FUNC("BUG: why am I validating an ignored function?", |