objtool: Fix ORC 'signal' propagation

There have been some recently reported ORC unwinder warnings like:

  WARNING: can't access registers at entry_SYSCALL_64_after_hwframe+0x63/0xcd
  WARNING: stack going in the wrong direction? at __sys_setsockopt+0x2c6/0x5b0 net/socket.c:2271

And a KASAN warning:

  BUG: KASAN: stack-out-of-bounds in unwind_next_frame (arch/x86/include/asm/ptrace.h:136 arch/x86/kernel/unwind_orc.c:455)

It turns out the 'signal' bit isn't getting propagated from the unwind
hints to the ORC entries, making the unwinder confused at times.

Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Reported-by: kernel test robot <oliver.sang@intel.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/97eef9db60cd86d376a9a40d49d77bb67a8f6526.1676579666.git.jpoimboe@kernel.org

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index b0b467d..5822de3 100644 (file)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2330,6 +2330,7 @@ static int read_unwind_hints(struct objtool_file *file)
 
                cfi.cfa.offset = bswap_if_needed(file->elf, hint->sp_offset);
                cfi.type = hint->type;
+               cfi.signal = hint->signal;
                cfi.end = hint->end;
 
                insn->cfi = cfi_hash_find_or_add(&cfi);

diff --git a/tools/objtool/include/objtool/cfi.h b/tools/objtool/include/objtool/cfi.h
index f11d1ac..b1258e7 100644 (file)
--- a/tools/objtool/include/objtool/cfi.h
+++ b/tools/objtool/include/objtool/cfi.h
@@ -34,6 +34,7 @@ struct cfi_state {
        unsigned char type;
        bool bp_scratch;
        bool drap;
+       bool signal;
        bool end;
 };
 

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 1f22b7e..57a4527 100644 (file)
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -27,6 +27,7 @@ static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
        }
 
        orc->end = cfi->end;
+       orc->signal = cfi->signal;
 
        if (cfi->cfa.base == CFI_UNDEFINED) {
                orc->sp_reg = ORC_REG_UNDEFINED;