* FAILED: patch "[PATCH] KVM: s390: Fix memory corruption by not reinjecting CK" failed to apply to 6.1-stable tree
@ 2026-09-09 10:35 gregkh
2026-09-11 12:05 ` [PATCH 6.1.y 1/2] s390: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-uapi headers Sasha Levin
0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2026-09-09 10:35 UTC (permalink / raw)
To: borntraeger, hca, imbrenda; +Cc: stable
The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 546dde823a36d7283dcf46127c2f3d093443860f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090945-quirk-camping-07b3@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 546dde823a36d7283dcf46127c2f3d093443860f Mon Sep 17 00:00:00 2001
From: Christian Borntraeger <borntraeger@linux.ibm.com>
Date: Thu, 6 Aug 2026 16:58:35 +0200
Subject: [PATCH] KVM: s390: Fix memory corruption by not reinjecting CK
machine checks
Channel-subsystem damage machine checks are for the host channel
subsystem. The guest channel subsystem is emulated in the userspace VMM.
There is no point in forwarding such machine checks into the guest.
This also simplifies the machine check reinjection and avoids kfree of a
stack variable as reported by sashiko. There might be still machine
checks that have the ck bit set with another bit (like instruction
damage), mask out the CK bit in s390_backup_mcck_info(), like the CP and
ED bits already are.
Fixes: 4d62fcc0b692 ("KVM: s390: Inject machine check into the guest")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260806145835.31818-1-borntraeger@linux.ibm.com>
diff --git a/arch/s390/include/asm/nmi.h b/arch/s390/include/asm/nmi.h
index 6454c1531854..7919b2b9ac9c 100644
--- a/arch/s390/include/asm/nmi.h
+++ b/arch/s390/include/asm/nmi.h
@@ -22,6 +22,7 @@
#define MCCK_CODE_SYSTEM_DAMAGE BIT(63)
#define MCCK_CODE_EXT_DAMAGE BIT(63 - 5)
#define MCCK_CODE_CP BIT(63 - 9)
+#define MCCK_CODE_CK BIT(63 - 11)
#define MCCK_CODE_STG_ERROR BIT(63 - 16)
#define MCCK_CODE_STG_KEY_ERROR BIT(63 - 18)
#define MCCK_CODE_STG_DEGRAD BIT(63 - 19)
@@ -33,6 +34,8 @@
#define MCCK_CODE_FC_VALID BIT(63 - 43)
#define MCCK_CODE_CPU_TIMER_VALID BIT(63 - 46)
+#define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE | MCCK_CODE_CK)
+
#ifndef __ASSEMBLER__
union mci {
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index e17a59d4d5a4..17297a8b63d9 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -344,8 +344,7 @@ static void notrace s390_backup_mcck_info(struct pt_regs *regs)
sie_page = container_of(sie_block, struct sie_page, sie_block);
mcck_backup = &sie_page->mcck_info;
- mcck_backup->mcic = get_lowcore()->mcck_interruption_code &
- ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE);
+ mcck_backup->mcic = get_lowcore()->mcck_interruption_code & ~MCCK_CODE_NO_GUEST;
mcck_backup->ext_damage_code = get_lowcore()->external_damage_code;
mcck_backup->failing_storage_address = get_lowcore()->failing_storage_address;
}
@@ -357,8 +356,6 @@ NOKPROBE_SYMBOL(s390_backup_mcck_info);
#define ED_STP_ISLAND 6 /* External damage STP island check */
#define ED_STP_SYNC 7 /* External damage STP sync check */
-#define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE)
-
/*
* machine check handler.
*/
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 009d6a845d59..0d9fbe75dc66 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -3108,9 +3108,7 @@ static int set_adapter_int(struct kvm_kernel_irq_routing_entry *e,
void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu,
struct mcck_volatile_info *mcck_info)
{
- struct kvm_s390_interrupt_info inti;
struct kvm_s390_irq irq = {};
- struct kvm_s390_mchk_info *mchk;
union mci mci;
__u64 cr14 = 0; /* upper bits are not used */
int rc;
@@ -3129,20 +3127,14 @@ void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu,
if (mci.w)
cr14 |= CR14_WARNING_SUBMASK;
- mchk = mci.ck ? &inti.mchk : &irq.u.mchk;
- mchk->cr14 = cr14;
- mchk->mcic = mcck_info->mcic;
- mchk->ext_damage_code = mcck_info->ext_damage_code;
- mchk->failing_storage_address = mcck_info->failing_storage_address;
- if (mci.ck) {
- /* Inject the floating machine check */
- inti.type = KVM_S390_MCHK;
- rc = __inject_vm(vcpu->kvm, &inti);
- } else {
- /* Inject the machine check to specified vcpu */
- irq.type = KVM_S390_MCHK;
- rc = kvm_s390_inject_vcpu(vcpu, &irq);
- }
+ irq.u.mchk.cr14 = cr14;
+ irq.u.mchk.mcic = mcck_info->mcic;
+ irq.u.mchk.ext_damage_code = mcck_info->ext_damage_code;
+ irq.u.mchk.failing_storage_address = mcck_info->failing_storage_address;
+
+ /* Inject the machine check to specified vcpu */
+ irq.type = KVM_S390_MCHK;
+ rc = kvm_s390_inject_vcpu(vcpu, &irq);
WARN_ON_ONCE(rc);
}
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 6.1.y 1/2] s390: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-uapi headers
2026-09-09 10:35 FAILED: patch "[PATCH] KVM: s390: Fix memory corruption by not reinjecting CK" failed to apply to 6.1-stable tree gregkh
@ 2026-09-11 12:05 ` Sasha Levin
2026-09-11 12:05 ` [PATCH 6.1.y 2/2] KVM: s390: Fix memory corruption by not reinjecting CK machine checks Sasha Levin
0 siblings, 1 reply; 3+ messages in thread
From: Sasha Levin @ 2026-09-11 12:05 UTC (permalink / raw)
To: stable; +Cc: Thomas Huth, Heiko Carstens, Alexander Gordeev, Sasha Levin
From: Thomas Huth <thuth@redhat.com>
[ Upstream commit 42398caf16c955251a2dab86f797b76adeb99899 ]
While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembler code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This is bad since macros starting with two underscores are names
that are reserved by the C language. It can also be very confusing
for the developers when switching between userspace and kernelspace
coding, or when dealing with uapi headers that rather should use
__ASSEMBLER__ instead. So let's now standardize on the __ASSEMBLER__
macro that is provided by the compilers.
This is a completely mechanical patch (done with a simple "sed -i"
statement), with some manual fixups done later while rebasing the
patch.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20250611140046.137739-3-thuth@redhat.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Stable dependency adaptation for 546dde823a36d7283dcf46127c2f3d093443860f:
Keep only the nmi.h guard conversion from the upstream patch. The other
header conversions do not prepare the machine-check fix; several headers
and the newer lowcore/alternative infrastructure are absent in 6.6.
Provide get_lowcore() as a macro alias for &S390_lowcore, retaining the
fixed-address lowcore semantics of this branch without adding a function.
Use that spelling for the three backup accesses and match upstream's
failing-storage-address assignment layout. Also zero-initialize the local
IRQ structure in kvm_s390_reinject_machine_check() to match the target's
context. These changes let the unmodified target patch apply cleanly.
The CK filtering and reinjection changes remain in the target commit.
[ sashal: Reduced backport -- upstream 42398caf16c95 touches 33 file(s), this
backport carries 4. Not backported here:
arch/s390/boot/boot.h
arch/s390/include/asm/alternative.h
arch/s390/include/asm/asm-const.h
arch/s390/include/asm/cpu.h
arch/s390/include/asm/cpu_mf-insn.h
arch/s390/include/asm/ctlreg.h
arch/s390/include/asm/dwarf.h
arch/s390/include/asm/extmem.h
... and 23 more
This note is generated from the file lists only; see the resolution record
for the reasoning. ]
Stable-dep-of: 546dde823a36 ("KVM: s390: Fix memory corruption by not reinjecting CK machine checks")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/include/asm/lowcore.h | 3 +++
arch/s390/include/asm/nmi.h | 4 ++--
arch/s390/kernel/nmi.c | 7 +++----
arch/s390/kvm/interrupt.c | 2 +-
4 files changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index 8aa1f6530a3e4..c64d744152dfa 100644
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -214,6 +214,9 @@ struct lowcore {
#define S390_lowcore (*((struct lowcore *) 0))
+/* Lowcore has a fixed address on this kernel. */
+#define get_lowcore() (&S390_lowcore)
+
extern struct lowcore *lowcore_ptr[];
static inline void set_prefix(__u32 address)
diff --git a/arch/s390/include/asm/nmi.h b/arch/s390/include/asm/nmi.h
index af1cd3a6f4060..418bb0aa714cc 100644
--- a/arch/s390/include/asm/nmi.h
+++ b/arch/s390/include/asm/nmi.h
@@ -33,7 +33,7 @@
#define MCCK_CODE_FC_VALID BIT(63 - 43)
#define MCCK_CODE_CPU_TIMER_VALID BIT(63 - 46)
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
union mci {
unsigned long val;
@@ -105,5 +105,5 @@ void s390_handle_mcck(struct pt_regs *regs);
void __s390_handle_mcck(void);
int s390_do_machine_check(struct pt_regs *regs);
-#endif /* __ASSEMBLY__ */
+#endif /* __ASSEMBLER__ */
#endif /* _ASM_S390_NMI_H */
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 31cb9b00a36bb..5c9d33ff92fda 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -372,11 +372,10 @@ static void notrace s390_backup_mcck_info(struct pt_regs *regs)
sie_page = container_of(sie_block, struct sie_page, sie_block);
mcck_backup = &sie_page->mcck_info;
- mcck_backup->mcic = S390_lowcore.mcck_interruption_code &
+ mcck_backup->mcic = get_lowcore()->mcck_interruption_code &
~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE);
- mcck_backup->ext_damage_code = S390_lowcore.external_damage_code;
- mcck_backup->failing_storage_address
- = S390_lowcore.failing_storage_address;
+ mcck_backup->ext_damage_code = get_lowcore()->external_damage_code;
+ mcck_backup->failing_storage_address = get_lowcore()->failing_storage_address;
}
NOKPROBE_SYMBOL(s390_backup_mcck_info);
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index a70540697ef34..6be9c79383dd5 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -2859,7 +2859,7 @@ void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu,
struct mcck_volatile_info *mcck_info)
{
struct kvm_s390_interrupt_info inti;
- struct kvm_s390_irq irq;
+ struct kvm_s390_irq irq = {};
struct kvm_s390_mchk_info *mchk;
union mci mci;
__u64 cr14 = 0; /* upper bits are not used */
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH 6.1.y 2/2] KVM: s390: Fix memory corruption by not reinjecting CK machine checks
2026-09-11 12:05 ` [PATCH 6.1.y 1/2] s390: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-uapi headers Sasha Levin
@ 2026-09-11 12:05 ` Sasha Levin
0 siblings, 0 replies; 3+ messages in thread
From: Sasha Levin @ 2026-09-11 12:05 UTC (permalink / raw)
To: stable; +Cc: Christian Borntraeger, Heiko Carstens, Claudio Imbrenda,
Sasha Levin
From: Christian Borntraeger <borntraeger@linux.ibm.com>
[ Upstream commit 546dde823a36d7283dcf46127c2f3d093443860f ]
Channel-subsystem damage machine checks are for the host channel
subsystem. The guest channel subsystem is emulated in the userspace VMM.
There is no point in forwarding such machine checks into the guest.
This also simplifies the machine check reinjection and avoids kfree of a
stack variable as reported by sashiko. There might be still machine
checks that have the ck bit set with another bit (like instruction
damage), mask out the CK bit in s390_backup_mcck_info(), like the CP and
ED bits already are.
Fixes: 4d62fcc0b692 ("KVM: s390: Inject machine check into the guest")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: <20260806145835.31818-1-borntraeger@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/include/asm/nmi.h | 3 +++
arch/s390/kernel/nmi.c | 5 +----
arch/s390/kvm/interrupt.c | 24 ++++++++----------------
3 files changed, 12 insertions(+), 20 deletions(-)
diff --git a/arch/s390/include/asm/nmi.h b/arch/s390/include/asm/nmi.h
index 418bb0aa714cc..418772b9ad664 100644
--- a/arch/s390/include/asm/nmi.h
+++ b/arch/s390/include/asm/nmi.h
@@ -22,6 +22,7 @@
#define MCCK_CODE_SYSTEM_DAMAGE BIT(63)
#define MCCK_CODE_EXT_DAMAGE BIT(63 - 5)
#define MCCK_CODE_CP BIT(63 - 9)
+#define MCCK_CODE_CK BIT(63 - 11)
#define MCCK_CODE_STG_ERROR BIT(63 - 16)
#define MCCK_CODE_STG_KEY_ERROR BIT(63 - 18)
#define MCCK_CODE_STG_DEGRAD BIT(63 - 19)
@@ -33,6 +34,8 @@
#define MCCK_CODE_FC_VALID BIT(63 - 43)
#define MCCK_CODE_CPU_TIMER_VALID BIT(63 - 46)
+#define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE | MCCK_CODE_CK)
+
#ifndef __ASSEMBLER__
union mci {
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 5c9d33ff92fda..bf05bf3a54338 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -372,8 +372,7 @@ static void notrace s390_backup_mcck_info(struct pt_regs *regs)
sie_page = container_of(sie_block, struct sie_page, sie_block);
mcck_backup = &sie_page->mcck_info;
- mcck_backup->mcic = get_lowcore()->mcck_interruption_code &
- ~(MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE);
+ mcck_backup->mcic = get_lowcore()->mcck_interruption_code & ~MCCK_CODE_NO_GUEST;
mcck_backup->ext_damage_code = get_lowcore()->external_damage_code;
mcck_backup->failing_storage_address = get_lowcore()->failing_storage_address;
}
@@ -385,8 +384,6 @@ NOKPROBE_SYMBOL(s390_backup_mcck_info);
#define ED_STP_ISLAND 6 /* External damage STP island check */
#define ED_STP_SYNC 7 /* External damage STP sync check */
-#define MCCK_CODE_NO_GUEST (MCCK_CODE_CP | MCCK_CODE_EXT_DAMAGE)
-
/*
* machine check handler.
*/
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 6be9c79383dd5..cd5f387c9b76b 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -2858,9 +2858,7 @@ static int set_adapter_int(struct kvm_kernel_irq_routing_entry *e,
void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu,
struct mcck_volatile_info *mcck_info)
{
- struct kvm_s390_interrupt_info inti;
struct kvm_s390_irq irq = {};
- struct kvm_s390_mchk_info *mchk;
union mci mci;
__u64 cr14 = 0; /* upper bits are not used */
int rc;
@@ -2873,20 +2871,14 @@ void kvm_s390_reinject_machine_check(struct kvm_vcpu *vcpu,
if (mci.w)
cr14 |= CR14_WARNING_SUBMASK;
- mchk = mci.ck ? &inti.mchk : &irq.u.mchk;
- mchk->cr14 = cr14;
- mchk->mcic = mcck_info->mcic;
- mchk->ext_damage_code = mcck_info->ext_damage_code;
- mchk->failing_storage_address = mcck_info->failing_storage_address;
- if (mci.ck) {
- /* Inject the floating machine check */
- inti.type = KVM_S390_MCHK;
- rc = __inject_vm(vcpu->kvm, &inti);
- } else {
- /* Inject the machine check to specified vcpu */
- irq.type = KVM_S390_MCHK;
- rc = kvm_s390_inject_vcpu(vcpu, &irq);
- }
+ irq.u.mchk.cr14 = cr14;
+ irq.u.mchk.mcic = mcck_info->mcic;
+ irq.u.mchk.ext_damage_code = mcck_info->ext_damage_code;
+ irq.u.mchk.failing_storage_address = mcck_info->failing_storage_address;
+
+ /* Inject the machine check to specified vcpu */
+ irq.type = KVM_S390_MCHK;
+ rc = kvm_s390_inject_vcpu(vcpu, &irq);
WARN_ON_ONCE(rc);
}
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-09-11 12:05 UTC | newest]
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2026-09-09 10:35 FAILED: patch "[PATCH] KVM: s390: Fix memory corruption by not reinjecting CK" failed to apply to 6.1-stable tree gregkh
2026-09-11 12:05 ` [PATCH 6.1.y 1/2] s390: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-uapi headers Sasha Levin
2026-09-11 12:05 ` [PATCH 6.1.y 2/2] KVM: s390: Fix memory corruption by not reinjecting CK machine checks Sasha Levin
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