From: Josh Poimboeuf Date: Tue, 8 Apr 2025 07:02:13 +0000 (-0700) Subject: objtool: Fix INSN_CONTEXT_SWITCH handling in validate_unret() X-Git-Tag: v6.15-rc2~21^2~5 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a8df7d0ef92eca28c610206c6748daf537ac0586;p=thirdparty%2Fkernel%2Flinux.git objtool: Fix INSN_CONTEXT_SWITCH handling in validate_unret() The !CONFIG_IA32_EMULATION version of xen_entry_SYSCALL_compat() ends with a SYSCALL instruction which is classified by objtool as INSN_CONTEXT_SWITCH. Unlike validate_branch(), validate_unret() doesn't consider INSN_CONTEXT_SWITCH in a non-function to be a dead end, so it keeps going past the end of xen_entry_SYSCALL_compat(), resulting in the following warning: vmlinux.o: warning: objtool: xen_reschedule_interrupt+0x2a: RET before UNTRAIN Fix that by adding INSN_CONTEXT_SWITCH handling to validate_unret() to match what validate_branch() is already doing. Fixes: a09a6e2399ba ("objtool: Add entry UNRET validation") Reported-by: Andrew Cooper Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/f5eda46fd09f15b1f5cde3d9ae3b92b958342add.1744095216.git.jpoimboe@kernel.org --- diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 4a1f6c3169b3b..c81b070ca4952 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3886,6 +3886,11 @@ static int validate_unret(struct objtool_file *file, struct instruction *insn) WARN_INSN(insn, "RET before UNTRAIN"); return 1; + case INSN_CONTEXT_SWITCH: + if (insn_func(insn)) + break; + return 0; + case INSN_NOP: if (insn->retpoline_safe) return 0;