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no mitigation available!" when the kernel lacks retpoline support, before returning SPECTRE_V2_NONE to its callers. SPECTRE_V2_NONE is not the final answer, though: spectre_v2_update_mitigation() runs afterwards and can still upgrade the mitigation. On an Intel CPU affected by RETBleed, built with CONFIG_MITIGATION_IBRS_ENTRY=y and CONFIG_MITIGATION_RETPOLINE=n, and booted with spectre_v2=auto, retbleed_select_mitigation() picks RETBLEED_MITIGATION_IBRS, and spectre_v2_update_mitigation() then promotes SPECTRE_V2_NONE to SPECTRE_V2_IBRS. The boot log claims no mitigation is available immediately before reporting "Spectre V2 : Mitigation: IBRS", and sysfs reports the machine as mitigated. The message is alarming and simply wrong. Drop the pr_err from the helper and emit it once from spectre_v2_update_mitigation(), after the final mitigation is known, so it only fires when the system really is left unmitigated. Guard it on !IS_ENABLED(CONFIG_MITIGATION_RETPOLINE) so it fires only when retpoline truly cannot be built in, and restrict it to the cases where retpoline was the implied choice: SPECTRE_V2_CMD_FORCE, or SPECTRE_V2_CMD_AUTO when should_mitigate_vuln(X86_BUG_SPECTRE_V2) indicates a mitigation was actually intended. Fixes: 480e803dacf8 ("x86/bugs: Restructure spectre_v2 mitigation") Cc: stable@kernel.org Signed-off-by: Kim Phillips Assisted-by: ClaudeCode:claude-opus-4-7 --- arch/x86/kernel/cpu/bugs.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 82436b3534fa..46c68feef339 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1956,10 +1956,8 @@ early_param("spectre_v2", spectre_v2_parse_cmdline); static enum spectre_v2_mitigation __init spectre_v2_select_retpoline(void) { - if (!IS_ENABLED(CONFIG_MITIGATION_RETPOLINE)) { - pr_err("Kernel not compiled with retpoline; no mitigation available!"); + if (!IS_ENABLED(CONFIG_MITIGATION_RETPOLINE)) return SPECTRE_V2_NONE; - } return SPECTRE_V2_RETPOLINE; } @@ -2247,6 +2245,13 @@ static void __init spectre_v2_update_mitigation(void) } } + if (!IS_ENABLED(CONFIG_MITIGATION_RETPOLINE) && + spectre_v2_enabled == SPECTRE_V2_NONE && + (spectre_v2_cmd == SPECTRE_V2_CMD_FORCE || + (spectre_v2_cmd == SPECTRE_V2_CMD_AUTO && + should_mitigate_vuln(X86_BUG_SPECTRE_V2)))) + pr_err("Kernel not compiled with retpoline; no mitigation available!"); + if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) pr_info("%s\n", spectre_v2_strings[spectre_v2_enabled]); } base-commit: 8d3ae59288f1e7d58d76558a6ee96d533bc5019f -- 2.43.0