* [PATCH] x86: Fix RCU list usage to avoid false positive warnings
@ 2020-04-30 19:29 madhuparnabhowmik10
2020-05-04 16:47 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: madhuparnabhowmik10 @ 2020-04-30 19:29 UTC (permalink / raw)
To: mingo, pbonzini, bp
Cc: x86, bhelgaas, sean.j.christopherson, cai, paulmck, joel,
linux-kernel-mentees, frextrite, linux-kernel, kvm, linux-pci,
Madhuparna Bhowmik
From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Use list_for_each_entry() instead of list_for_each_entry_rcu() whenever
spinlock or mutex is always held.
Otherwise, pass cond to list_for_each_entry_rcu().
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
---
arch/x86/kernel/nmi.c | 2 +-
arch/x86/kvm/irq_comm.c | 3 ++-
arch/x86/pci/mmconfig-shared.c | 2 +-
3 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 6407ea21fa1b..999dc6c134d2 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -195,7 +195,7 @@ void unregister_nmi_handler(unsigned int type, const char *name)
raw_spin_lock_irqsave(&desc->lock, flags);
- list_for_each_entry_rcu(n, &desc->head, list) {
+ list_for_each_entry(n, &desc->head, list) {
/*
* the name passed in to describe the nmi handler
* is used as the lookup key
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index c47d2acec529..5b88a648e079 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -258,7 +258,8 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
idx = srcu_read_lock(&kvm->irq_srcu);
gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
if (gsi != -1)
- hlist_for_each_entry_rcu(kimn, &kvm->arch.mask_notifier_list, link)
+ hlist_for_each_entry_rcu(kimn, &kvm->arch.mask_notifier_list, link,
+ srcu_read_lock_held(&kvm->irq_srcu))
if (kimn->irq == gsi)
kimn->func(kimn, mask);
srcu_read_unlock(&kvm->irq_srcu, idx);
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 6fa42e9c4e6f..a096942690bd 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -797,7 +797,7 @@ int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
struct pci_mmcfg_region *cfg;
mutex_lock(&pci_mmcfg_lock);
- list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
+ list_for_each_entry(cfg, &pci_mmcfg_list, list)
if (cfg->segment == seg && cfg->start_bus == start &&
cfg->end_bus == end) {
list_del_rcu(&cfg->list);
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] x86: Fix RCU list usage to avoid false positive warnings
2020-04-30 19:29 [PATCH] x86: Fix RCU list usage to avoid false positive warnings madhuparnabhowmik10
@ 2020-05-04 16:47 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2020-05-04 16:47 UTC (permalink / raw)
To: madhuparnabhowmik10, mingo, bp
Cc: x86, bhelgaas, sean.j.christopherson, cai, paulmck, joel,
linux-kernel-mentees, frextrite, linux-kernel, kvm, linux-pci
On 30/04/20 21:29, madhuparnabhowmik10@gmail.com wrote:
> From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>
> Use list_for_each_entry() instead of list_for_each_entry_rcu() whenever
> spinlock or mutex is always held.
> Otherwise, pass cond to list_for_each_entry_rcu().
>
> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
> ---
> arch/x86/kernel/nmi.c | 2 +-
> arch/x86/kvm/irq_comm.c | 3 ++-
> arch/x86/pci/mmconfig-shared.c | 2 +-
> 3 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
> index 6407ea21fa1b..999dc6c134d2 100644
> --- a/arch/x86/kernel/nmi.c
> +++ b/arch/x86/kernel/nmi.c
> @@ -195,7 +195,7 @@ void unregister_nmi_handler(unsigned int type, const char *name)
>
> raw_spin_lock_irqsave(&desc->lock, flags);
>
> - list_for_each_entry_rcu(n, &desc->head, list) {
> + list_for_each_entry(n, &desc->head, list) {
> /*
> * the name passed in to describe the nmi handler
> * is used as the lookup key
> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
> index c47d2acec529..5b88a648e079 100644
> --- a/arch/x86/kvm/irq_comm.c
> +++ b/arch/x86/kvm/irq_comm.c
> @@ -258,7 +258,8 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
> idx = srcu_read_lock(&kvm->irq_srcu);
> gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
> if (gsi != -1)
> - hlist_for_each_entry_rcu(kimn, &kvm->arch.mask_notifier_list, link)
> + hlist_for_each_entry_rcu(kimn, &kvm->arch.mask_notifier_list, link,
> + srcu_read_lock_held(&kvm->irq_srcu))
> if (kimn->irq == gsi)
> kimn->func(kimn, mask);
> srcu_read_unlock(&kvm->irq_srcu, idx);
> diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
> index 6fa42e9c4e6f..a096942690bd 100644
> --- a/arch/x86/pci/mmconfig-shared.c
> +++ b/arch/x86/pci/mmconfig-shared.c
> @@ -797,7 +797,7 @@ int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
> struct pci_mmcfg_region *cfg;
>
> mutex_lock(&pci_mmcfg_lock);
> - list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
> + list_for_each_entry(cfg, &pci_mmcfg_list, list)
> if (cfg->segment == seg && cfg->start_bus == start &&
> cfg->end_bus == end) {
> list_del_rcu(&cfg->list);
>
For KVM parts, if the x86 maintainers want to apply the whole patch,
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-05-04 16:47 ` Paolo Bonzini
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