extlog_init() uses rdmsrl() to read an MSR, which on older CPUs
provokes a error message at boot:
unchecked MSR access error: RDMSR from 0x179 at rIP: 0xcd047307 (native_read_msr+0x7/0x40)
Use rdmsrl_safe() instead, and return -ENODEV if it fails.
Reported-by: jim@photojim.ca
References: https://bugs.debian.org/971058
Cc: stable@vger.kernel.org
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/acpi/acpi_extlog.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
index f138e12b7b82..72f1fb77abcd 100644
--- a/drivers/acpi/acpi_extlog.c
+++ b/drivers/acpi/acpi_extlog.c
@@ -222,9 +222,9 @@ static int __init extlog_init(void)
u64 cap;
int rc;
- rdmsrl(MSR_IA32_MCG_CAP, cap);
-
- if (!(cap & MCG_ELOG_P) || !extlog_get_l1addr())
+ if (rdmsrl_safe(MSR_IA32_MCG_CAP, &cap) ||
+ !(cap & MCG_ELOG_P) ||
+ !extlog_get_l1addr())
return -ENODEV;
rc = -EINVAL;
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