linux-kernel - [PATCH v7 01/31] objtool: Make validate_call() recognize indirect calls to pv

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Message-ID: <20251114150133.1056710-2-vschneid@redhat.com>
Date: Fri, 14 Nov 2025 16:01:03 +0100
From: Valentin Schneider <vschneid@...hat.com>
To: linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	rcu@...r.kernel.org,
	x86@...nel.org,
	linux-arm-kernel@...ts.infradead.org,
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Cc: Josh Poimboeuf <jpoimboe@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
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	Andrew Morton <akpm@...ux-foundation.org>,
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	Marcelo Tosatti <mtosatti@...hat.com>,
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	Shrikanth Hegde <sshegde@...ux.ibm.com>
Subject: [PATCH v7 01/31] objtool: Make validate_call() recognize indirect calls to pv_ops[]

call_dest_name() does not get passed the file pointer of validate_call(),
which means its invocation of insn_reloc() will always return NULL. Make it
take a file pointer.

While at it, make sure call_dest_name() uses arch_dest_reloc_offset(),
otherwise it gets the pv_ops[] offset wrong.

Fabricating an intentional warning shows the change; previously:

  vmlinux.o: warning: objtool: __flush_tlb_all_noinstr+0x4: call to {dynamic}() leaves .noinstr.text section

now:

  vmlinux.o: warning: objtool: __flush_tlb_all_noinstr+0x4: call to pv_ops[1]() leaves .noinstr.text section

Signed-off-by: Valentin Schneider <vschneid@...hat.com>
Acked-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 tools/objtool/check.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 9004fbc067693..12b6967e5fd0d 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3325,7 +3325,7 @@ static inline bool func_uaccess_safe(struct symbol *func)
 	return false;
 }
 
-static inline const char *call_dest_name(struct instruction *insn)
+static inline const char *call_dest_name(struct objtool_file *file, struct instruction *insn)
 {
 	static char pvname[19];
 	struct reloc *reloc;
@@ -3334,9 +3334,9 @@ static inline const char *call_dest_name(struct instruction *insn)
 	if (insn_call_dest(insn))
 		return insn_call_dest(insn)->name;
 
-	reloc = insn_reloc(NULL, insn);
+	reloc = insn_reloc(file, insn);
 	if (reloc && !strcmp(reloc->sym->name, "pv_ops")) {
-		idx = (reloc_addend(reloc) / sizeof(void *));
+		idx = (arch_dest_reloc_offset(reloc_addend(reloc)) / sizeof(void *));
 		snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx);
 		return pvname;
 	}
@@ -3415,17 +3415,19 @@ static int validate_call(struct objtool_file *file,
 {
 	if (state->noinstr && state->instr <= 0 &&
 	    !noinstr_call_dest(file, insn, insn_call_dest(insn))) {
-		WARN_INSN(insn, "call to %s() leaves .noinstr.text section", call_dest_name(insn));
+		WARN_INSN(insn, "call to %s() leaves .noinstr.text section", call_dest_name(file, insn));
 		return 1;
 	}
 
 	if (state->uaccess && !func_uaccess_safe(insn_call_dest(insn))) {
-		WARN_INSN(insn, "call to %s() with UACCESS enabled", call_dest_name(insn));
+		WARN_INSN(insn, "call to %s() with UACCESS enabled",
+			  call_dest_name(file, insn));
 		return 1;
 	}
 
 	if (state->df) {
-		WARN_INSN(insn, "call to %s() with DF set", call_dest_name(insn));
+		WARN_INSN(insn, "call to %s() with DF set",
+			  call_dest_name(file, insn));
 		return 1;
 	}
 
-- 
2.51.0