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authorJosh Poimboeuf <jpoimboe@kernel.org>2024-02-27 10:35:27 +0300
committerKees Cook <keescook@chromium.org>2024-03-01 09:34:42 +0300
commit10b4c4bce3f5541f54bcc2039720b11d2bc96d79 (patch)
tree87d1ec639788aaf83ab690eeb4c49986f08a113e /tools/objtool
parentc5e6d3d85efa7451590edd94725b4b280e2fd8a3 (diff)
downloadlinux-10b4c4bce3f5541f54bcc2039720b11d2bc96d79.tar.xz
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>
Diffstat (limited to 'tools/objtool')
-rw-r--r--tools/objtool/check.c12
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;
}