The patch titled
Subject: kasan: prevent cpu_quarantine corruption when CPU offline and cache shrink occur at same time
has been removed from the -mm tree. Its filename was
kasan-prevent-cpu_quarantine-corruption-when-cpu-offline-and-cache-shrink-occur-at-same-time.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Zqiang <qiang1.zhang(a)intel.com>
Subject: kasan: prevent cpu_quarantine corruption when CPU offline and cache shrink occur at same time
kasan_quarantine_remove_cache() is called in kmem_cache_shrink()/
destroy(). The kasan_quarantine_remove_cache() call is protected by
cpuslock in kmem_cache_destroy() to ensure serialization with
kasan_cpu_offline().
However the kasan_quarantine_remove_cache() call is not protected by
cpuslock in kmem_cache_shrink(). When a CPU is going offline and cache
shrink occurs at same time, the cpu_quarantine may be corrupted by
interrupt (per_cpu_remove_cache operation).
So add a cpu_quarantine offline flags check in per_cpu_remove_cache().
[akpm(a)linux-foundation.org: add comment, per Zqiang]
Link: https://lkml.kernel.org/r/20220414025925.2423818-1-qiang1.zhang@intel.com
Signed-off-by: Zqiang <qiang1.zhang(a)intel.com>
Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com>
Cc: Andrey Ryabinin <ryabinin.a.a(a)gmail.com>
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Andrey Konovalov <andreyknvl(a)gmail.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/kasan/quarantine.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/kasan/quarantine.c~kasan-prevent-cpu_quarantine-corruption-when-cpu-offline-and-cache-shrink-occur-at-same-time
+++ a/mm/kasan/quarantine.c
@@ -315,6 +315,13 @@ static void per_cpu_remove_cache(void *a
struct qlist_head *q;
q = this_cpu_ptr(&cpu_quarantine);
+ /*
+ * Ensure the ordering between the writing to q->offline and
+ * per_cpu_remove_cache. Prevent cpu_quarantine from being corrupted
+ * by interrupt.
+ */
+ if (READ_ONCE(q->offline))
+ return;
qlist_move_cache(q, &to_free, cache);
qlist_free_all(&to_free, cache);
}
_
Patches currently in -mm which might be from qiang1.zhang(a)intel.com are
kasan-fix-sleeping-function-called-from-invalid-context-on-rt-kernel.patch
kvm_vcpu_check_block is called while not in TASK_RUNNING, and therefore
cannot sleep. Writing to guest memory is therefore forbidden, but it
can happen if kvm_check_nested_events causes a vmexit.
Fortunately, all events that are caught by kvm_check_nested_events are
also handled by kvm_vcpu_has_events through vendor callbacks such as
kvm_x86_interrupt_allowed or kvm_x86_ops.nested_ops->has_events, so
remove the call.
Cc: stable(a)vger.kernel.org
Reported-by: Maxim Levitsky <mlevitsk(a)redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
---
arch/x86/kvm/x86.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d563812ca229..90b4f50b9a84 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10341,9 +10341,6 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu)
static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
{
- if (is_guest_mode(vcpu))
- kvm_check_nested_events(vcpu);
-
return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
!vcpu->arch.apf.halted);
}
--
2.31.1
From: Zqiang <qiang1.zhang(a)intel.com>
Subject: kasan: prevent cpu_quarantine corruption when CPU offline and cache shrink occur at same time
kasan_quarantine_remove_cache() is called in kmem_cache_shrink()/
destroy(). The kasan_quarantine_remove_cache() call is protected by
cpuslock in kmem_cache_destroy() to ensure serialization with
kasan_cpu_offline().
However the kasan_quarantine_remove_cache() call is not protected by
cpuslock in kmem_cache_shrink(). When a CPU is going offline and cache
shrink occurs at same time, the cpu_quarantine may be corrupted by
interrupt (per_cpu_remove_cache operation).
So add a cpu_quarantine offline flags check in per_cpu_remove_cache().
[akpm(a)linux-foundation.org: add comment, per Zqiang]
Link: https://lkml.kernel.org/r/20220414025925.2423818-1-qiang1.zhang@intel.com
Signed-off-by: Zqiang <qiang1.zhang(a)intel.com>
Reviewed-by: Dmitry Vyukov <dvyukov(a)google.com>
Cc: Andrey Ryabinin <ryabinin.a.a(a)gmail.com>
Cc: Alexander Potapenko <glider(a)google.com>
Cc: Andrey Konovalov <andreyknvl(a)gmail.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/kasan/quarantine.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/kasan/quarantine.c~kasan-prevent-cpu_quarantine-corruption-when-cpu-offline-and-cache-shrink-occur-at-same-time
+++ a/mm/kasan/quarantine.c
@@ -315,6 +315,13 @@ static void per_cpu_remove_cache(void *a
struct qlist_head *q;
q = this_cpu_ptr(&cpu_quarantine);
+ /*
+ * Ensure the ordering between the writing to q->offline and
+ * per_cpu_remove_cache. Prevent cpu_quarantine from being corrupted
+ * by interrupt.
+ */
+ if (READ_ONCE(q->offline))
+ return;
qlist_move_cache(q, &to_free, cache);
qlist_free_all(&to_free, cache);
}
_