x86/MCE/AMD: Always give panic severity for UC errors in kernel context
Borislav Petkov
maintainerPATCH 1/2 x86/MCE/AMD: Always give panic severity for UC errors in kernel context
From: Yazen Ghannam <[email protected]>
The AMD severity grading function was introduced in kernel 4.1. The current logic can possibly give MCE_AR_SEVERITY for uncorrectable errors in kernel context. The system may then get stuck in a loop as memory_failure() will try to handle the bad kernel memory and find it busy.
Return MCE_PANIC_SEVERITY for all UC errors IN_KERNEL context on AMD systems.
After:
b2f9d678e28c ("x86/mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries")
was accepted in v4.6, this issue was masked because of the tail-end attempt at kernel mode recovery in the #MC handler.
However, uncorrectable errors IN_KERNEL context should always be considered unrecoverable and cause a panic.
--- arch/x86/kernel/cpu/mcheck/mce-severity.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
arch/x86/kernel/cpu/mcheck/mce-severity.c +3 -4
@@ -245,6 +245,9 @@ static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_excif (m->status &MCI_STATUS_UC ) { +if (ctx ==IN_KERNEL ) +return MCE_PANIC_SEVERITY ; +/* * On older systems where overflow_recov flag is not present, we * should simply panic if an error overflow occurs. If
@@ -255,10 +258,6 @@ static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_excif (mce_flags.smca)return mce_severity_amd_smca (m, ctx); -/* software can try to contain */ -if (!(m->mcgstatus &MCG_STATUS_RIPV ) && (ctx ==IN_KERNEL )) -return MCE_PANIC_SEVERITY ; -/* kill current process */ return MCE_AR_SEVERITY ; }else {
Signature · 1 line
2.13.0
Borislav Petkov
maintainerPATCH 2/2 x86/MCE/AMD: Fix mce_severity_amd_smca() signature
From: Yazen Ghannam <[email protected]>
Change the err_ctx type to "enum context" to match the type passed in.
No functionality change.
--- arch/x86/kernel/cpu/mcheck/mce-severity.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kernel/cpu/mcheck/mce-severity.c +1 -1
@@ -204,7 +204,7 @@ static int error_context(struct mce *m)return IN_KERNEL ; } -static int mce_severity_amd_smca (struct mce *m,int err_ctx) +static int mce_severity_amd_smca (struct mce *m,enum context err_ctx) {u32 addr =MSR_AMD64_SMCA_MCx_CONFIG (m->bank);u32 low, high;
Signature · 1 line
2.13.0
tip-bot for Yazen Ghannam
merge bot[tip:ras/core] x86/MCE/AMD: Fix mce_severity_amd_smca() signature
x86/MCE/AMD: Fix mce_severity_amd_smca() signature
Commit-ID: 783ca517bfd62ca516178712775e4b273292d5b1 Gitweb: https://git.kernel.org/tip/783ca517bfd62ca516178712775e4b273292d5b1 Author: Yazen Ghannam <[email protected]> AuthorDate: Mon, 6 Nov 2017 18:46:33 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 7 Nov 2017 11:07:50 +0100
x86/MCE/AMD: Fix mce_severity_amd_smca() signature
Change the err_ctx type to "enum context" to match the type passed in.
No functionality change.
--- arch/x86/kernel/cpu/mcheck/mce-severity.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--
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arch/x86/kernel/cpu/mcheck/mce-severity.c +1 -1
@@ -204,7 +204,7 @@ static int error_context(struct mce *m)return IN_KERNEL ; } -static int mce_severity_amd_smca (struct mce *m,int err_ctx) +static int mce_severity_amd_smca (struct mce *m,enum context err_ctx) {u32 addr =MSR_AMD64_SMCA_MCx_CONFIG (m->bank);u32 low, high;
tip-bot for Yazen Ghannam
merge botx86/MCE/AMD: Always give panic severity for UC errors in kernel context
Commit-ID: d65dfc81bb3894fdb68cbc74bbf5fb48d2354071 Gitweb: https://git.kernel.org/tip/d65dfc81bb3894fdb68cbc74bbf5fb48d2354071 Author: Yazen Ghannam <[email protected]> AuthorDate: Mon, 6 Nov 2017 18:46:32 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 7 Nov 2017 11:07:50 +0100
x86/MCE/AMD: Always give panic severity for UC errors in kernel context
The AMD severity grading function was introduced in kernel 4.1. The current logic can possibly give MCE_AR_SEVERITY for uncorrectable errors in kernel context. The system may then get stuck in a loop as memory_failure() will try to handle the bad kernel memory and find it busy.
Return MCE_PANIC_SEVERITY for all UC errors IN_KERNEL context on AMD systems.
After:
b2f9d678e28c ("x86/mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries")
was accepted in v4.6, this issue was masked because of the tail-end attempt at kernel mode recovery in the #MC handler.
However, uncorrectable errors IN_KERNEL context should always be considered unrecoverable and cause a panic.
--- arch/x86/kernel/cpu/mcheck/mce-severity.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
--
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arch/x86/kernel/cpu/mcheck/mce-severity.c +3 -4
@@ -245,6 +245,9 @@ static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_excif (m->status &MCI_STATUS_UC ) { +if (ctx ==IN_KERNEL ) +return MCE_PANIC_SEVERITY ; +/* * On older systems where overflow_recov flag is not present, we * should simply panic if an error overflow occurs. If
@@ -255,10 +258,6 @@ static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_excif (mce_flags.smca)return mce_severity_amd_smca (m, ctx); -/* software can try to contain */ -if (!(m->mcgstatus &MCG_STATUS_RIPV ) && (ctx ==IN_KERNEL )) -return MCE_PANIC_SEVERITY ; -/* kill current process */ return MCE_AR_SEVERITY ; }else {