This patch move the wake_up() call at the point when a remove message
completed. Before it was only when a remove message was going to be
sent. The possible waiter in wait_pending_remove() waits until a remove
is done if the resource name matches with the per ls variable
ls->ls_remove_name. If this is the case we must wait until a pending
remove is done which is indicated if DLM_WAIT_PENDING_COND() returns
false which will always be the case when ls_remove_len and
ls_remove_name are unset to indicate that a remove is not going on
anymore.
Fixes: 21d9ac1a5376 ("fs: dlm: use event based wait for pending remove")
Cc: stable(a)vger.kernel.org
Signed-off-by: Alexander Aring <aahringo(a)redhat.com>
---
fs/dlm/lock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 29e80039e7ca..137cf09b51e5 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1810,7 +1810,6 @@ static void shrink_bucket(struct dlm_ls *ls, int b)
memcpy(ls->ls_remove_name, name, DLM_RESNAME_MAXLEN);
spin_unlock(&ls->ls_remove_spin);
spin_unlock(&ls->ls_rsbtbl[b].lock);
- wake_up(&ls->ls_remove_wait);
send_remove(r);
@@ -1819,6 +1818,7 @@ static void shrink_bucket(struct dlm_ls *ls, int b)
ls->ls_remove_len = 0;
memset(ls->ls_remove_name, 0, DLM_RESNAME_MAXLEN);
spin_unlock(&ls->ls_remove_spin);
+ wake_up(&ls->ls_remove_wait);
dlm_free_rsb(r);
}
@@ -4096,7 +4096,6 @@ static void send_repeat_remove(struct dlm_ls *ls, char *ms_name, int len)
memcpy(ls->ls_remove_name, name, DLM_RESNAME_MAXLEN);
spin_unlock(&ls->ls_remove_spin);
spin_unlock(&ls->ls_rsbtbl[b].lock);
- wake_up(&ls->ls_remove_wait);
rv = _create_message(ls, sizeof(struct dlm_message) + len,
dir_nodeid, DLM_MSG_REMOVE, &ms, &mh);
@@ -4112,6 +4111,7 @@ static void send_repeat_remove(struct dlm_ls *ls, char *ms_name, int len)
ls->ls_remove_len = 0;
memset(ls->ls_remove_name, 0, DLM_RESNAME_MAXLEN);
spin_unlock(&ls->ls_remove_spin);
+ wake_up(&ls->ls_remove_wait);
}
static int receive_request(struct dlm_ls *ls, struct dlm_message *ms)
--
2.31.1
kvm_vcpu_release() will call kvm_dirty_ring_free(), freeing
ring->dirty_gfns and setting it to NULL. Afterwards, it calls
kvm_arch_vcpu_destroy().
However, if closing the file descriptor races with KVM_RUN in such away
that vcpu->arch.st.preempted == 0, the following call stack leads to a
NULL pointer dereference in kvm_dirty_run_push():
mark_page_dirty_in_slot+0x192/0x270 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3171
kvm_steal_time_set_preempted arch/x86/kvm/x86.c:4600 [inline]
kvm_arch_vcpu_put+0x34e/0x5b0 arch/x86/kvm/x86.c:4618
vcpu_put+0x1b/0x70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:211
vmx_free_vcpu+0xcb/0x130 arch/x86/kvm/vmx/vmx.c:6985
kvm_arch_vcpu_destroy+0x76/0x290 arch/x86/kvm/x86.c:11219
kvm_vcpu_destroy arch/x86/kvm/../../../virt/kvm/kvm_main.c:441 [inline]
The fix is to release the dirty page ring after kvm_arch_vcpu_destroy
has run.
Reported-by: Qiuhao Li <qiuhao(a)sysec.org>
Reported-by: Gaoning Pan <pgn(a)zju.edu.cn>
Reported-by: Yongkang Jia <kangel(a)zju.edu.cn>
Cc: stable(a)vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com>
---
virt/kvm/kvm_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 70e05af5ebea..b22f380e3347 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -434,8 +434,8 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
- kvm_dirty_ring_free(&vcpu->dirty_ring);
kvm_arch_vcpu_destroy(vcpu);
+ kvm_dirty_ring_free(&vcpu->dirty_ring);
/*
* No need for rcu_read_lock as VCPU_RUN is the only place that changes
--
2.31.1