6.6-stable review patch. If anyone has any objections, please let me know.
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From: David Kaplan david.kaplan@amd.com
[ Upstream commit d1cc1baef67ac6c09b74629ca053bf3fb812f7dc ]
The LFENCE retpoline mitigation is not secure but the kernel prints inconsistent messages about this fact. The dmesg log says 'Mitigation: LFENCE', implying the system is mitigated. But sysfs reports 'Vulnerable: LFENCE' implying the system (correctly) is not mitigated.
Fix this by printing a consistent 'Vulnerable: LFENCE' string everywhere when this mitigation is selected.
Signed-off-by: David Kaplan david.kaplan@amd.com Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Link: https://lore.kernel.org/20250915134706.3201818-1-david.kaplan@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/cpu/bugs.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index f66e0e5b49eb1..ef1d3a5024ed4 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -1594,7 +1594,7 @@ spectre_v2_user_select_mitigation(void) static const char * const spectre_v2_strings[] = { [SPECTRE_V2_NONE] = "Vulnerable", [SPECTRE_V2_RETPOLINE] = "Mitigation: Retpolines", - [SPECTRE_V2_LFENCE] = "Mitigation: LFENCE", + [SPECTRE_V2_LFENCE] = "Vulnerable: LFENCE", [SPECTRE_V2_EIBRS] = "Mitigation: Enhanced / Automatic IBRS", [SPECTRE_V2_EIBRS_LFENCE] = "Mitigation: Enhanced / Automatic IBRS + LFENCE", [SPECTRE_V2_EIBRS_RETPOLINE] = "Mitigation: Enhanced / Automatic IBRS + Retpolines", @@ -3222,9 +3222,6 @@ static const char *spectre_bhi_state(void)
static ssize_t spectre_v2_show_state(char *buf) { - if (spectre_v2_enabled == SPECTRE_V2_LFENCE) - return sysfs_emit(buf, "Vulnerable: LFENCE\n"); - if (spectre_v2_enabled == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled()) return sysfs_emit(buf, "Vulnerable: eIBRS with unprivileged eBPF\n");