Re: [PATCH v3 1/3] x86/mce: Use is_copy_from_user() to determine copy-from-user context

Shuai Xue
2025-03-07T01:40:12Z

在 2025/3/7 02:15, Luck, Tony 写道:
>> diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
>> index dac4d64dfb2a..cb021058165f 100644
>> --- a/arch/x86/kernel/cpu/mce/severity.c
>> +++ b/arch/x86/kernel/cpu/mce/severity.c
>> @@ -300,13 +300,12 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs)
>> copy_user = is_copy_from_user(regs);
>> instrumentation_end();
>>
>> - switch (fixup_type) {
>> - case EX_TYPE_UACCESS:
>> - if (!copy_user)
>> - return IN_KERNEL;
>> - m->kflags |= MCE_IN_KERNEL_COPYIN;
>> - fallthrough;
>> + if (copy_user) {
>> + m->kflags |= MCE_IN_KERNEL_COPYIN | MCE_IN_KERNEL_COPYIN;
>
> You have " MCE_IN_KERNEL_COPYIN" twice here.

Sorry, I forgot to format a new patch and send a old version.
The corrected one:

---
arch/x86/kernel/cpu/mce/severity.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index dac4d64dfb2a..2235a7477436 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -300,13 +300,12 @@ static noinstr int error_context(struct mce *m, struct pt_regs *regs)
copy_user = is_copy_from_user(regs);
instrumentation_end();

- switch (fixup_type) {
- case EX_TYPE_UACCESS:
- if (!copy_user)
- return IN_KERNEL;
- m->kflags |= MCE_IN_KERNEL_COPYIN;
- fallthrough;
+ if (copy_user) {
+ m->kflags |= MCE_IN_KERNEL_COPYIN | MCE_IN_KERNEL_RECOV;
+ return IN_KERNEL_RECOV;
+ }

+ switch (fixup_type) {
case EX_TYPE_FAULT_MCE_SAFE:
case EX_TYPE_DEFAULT_MCE_SAFE:
m->kflags |= MCE_IN_KERNEL_RECOV;

Will fix it in next version.

Thanks.
Shuai