diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2024-02-26 23:35:27 -0800 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2024-02-29 22:34:42 -0800 |
| commit | 10b4c4bce3f5541f54bcc2039720b11d2bc96d79 (patch) | |
| tree | 87d1ec639788aaf83ab690eeb4c49986f08a113e | |
| parent | c5e6d3d85efa7451590edd94725b4b280e2fd8a3 (diff) | |
objtool: Fix UNWIND_HINT_{SAVE,RESTORE} across basic blocks
If SAVE and RESTORE unwind hints are in different basic blocks, and
objtool sees the RESTORE before the SAVE, it errors out with:
vmlinux.o: warning: objtool: vmw_port_hb_in+0x242: objtool isn't smart enough to handle this CFI save/restore combo
In such a case, defer following the RESTORE block until the
straight-line path gets followed later.
Fixes: 8faea26e6111 ("objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402240702.zJFNmahW-lkp@intel.com/
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20240227073527.avcm5naavbv3cj5s@treble
Signed-off-by: Kees Cook <keescook@chromium.org>
| -rw-r--r-- | tools/objtool/check.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 548ec3cd7c00..c4c2f75eadfd 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3620,6 +3620,18 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, } if (!save_insn->visited) { + /* + * If the restore hint insn is at the + * beginning of a basic block and was + * branched to from elsewhere, and the + * save insn hasn't been visited yet, + * defer following this branch for now. + * It will be seen later via the + * straight-line path. + */ + if (!prev_insn) + return 0; + WARN_INSN(insn, "objtool isn't smart enough to handle this CFI save/restore combo"); return 1; } |