This is a note to let you know that I've just added the patch titled
objtool/x86: Fixup frame-pointer vs rethunk
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
objtool-x86-fixup-frame-pointer-vs-rethunk.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From dbf46008775516f7f25c95b7760041c286299783 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Wed, 16 Aug 2023 13:59:21 +0200
Subject: objtool/x86: Fixup frame-pointer vs rethunk
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit dbf46008775516f7f25c95b7760041c286299783 upstream.
For stack-validation of a frame-pointer build, objtool validates that
every CALL instruction is preceded by a frame-setup. The new SRSO
return thunks violate this with their RSB stuffing trickery.
Extend the __fentry__ exception to also cover the embedded_insn case
used for this. This cures:
vmlinux.o: warning: objtool: srso_untrain_ret+0xd: call without frame pointer save/setup
Fixes: 4ae68b26c3ab ("objtool/x86: Fix SRSO mess")
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230816115921.GH980931@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/objtool/check.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2174,12 +2174,17 @@ static int decode_sections(struct objtoo
return 0;
}
-static bool is_fentry_call(struct instruction *insn)
+static bool is_special_call(struct instruction *insn)
{
- if (insn->type == INSN_CALL &&
- insn->call_dest &&
- insn->call_dest->fentry)
- return true;
+ if (insn->type == INSN_CALL) {
+ struct symbol *dest = insn->call_dest;
+
+ if (!dest)
+ return false;
+
+ if (dest->fentry)
+ return true;
+ }
return false;
}
@@ -3125,7 +3130,7 @@ static int validate_branch(struct objtoo
if (ret)
return ret;
- if (!no_fp && func && !is_fentry_call(insn) &&
+ if (!no_fp && func && !is_special_call(insn) &&
!has_valid_stack_frame(&state)) {
WARN_FUNC("call without frame pointer save/setup",
sec, insn->offset);
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-5.15/x86-cpu-fix-up-srso_safe_ret-and-__x86_return_thunk.patch
queue-5.15/x86-static_call-fix-__static_call_fixup.patch
queue-5.15/x86-cpu-cleanup-the-untrain-mess.patch
queue-5.15/iopoll-call-cpu_relax-in-busy-loops.patch
queue-5.15/objtool-x86-fixup-frame-pointer-vs-rethunk.patch
queue-5.15/x86-retpoline-kprobes-fix-position-of-thunk-sections-with-config_lto_clang.patch
queue-5.15/x86-cpu-rename-srso_-.-_alias-to-srso_alias_-1.patch
queue-5.15/x86-alternative-make-custom-return-thunk-unconditional.patch
queue-5.15/x86-cpu-rename-original-retbleed-methods.patch
queue-5.15/x86-cpu-clean-up-srso-return-thunk-mess.patch
queue-5.15/x86-cpu-fix-__x86_return_thunk-symbol-type.patch
