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| author |   Josh Poimboeuf <jpoimboe@redhat.com> | 2019-05-13 12:01:32 -0500 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2019-05-13 20:31:17 +0200 |
| commit | e6f393bc939d566ce3def71232d8013de9aaadde (patch) | |
| tree | 2829dfebc1b7fcc5b35e1b1c92af0e9cb0b54dec /tools/objtool | |
| parent | objtool: Don't use ignore flag for fake jumps (diff) | |
| download | wireguard-linux-e6f393bc939d566ce3def71232d8013de9aaadde.tar.xz wireguard-linux-e6f393bc939d566ce3def71232d8013de9aaadde.zip | |
objtool: Fix function fallthrough detection
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>
Diffstat (limited to 'tools/objtool')
| -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 90226791df6b..7325d89ccad9 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1959,7 +1959,8 @@ 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?", |