From b1ad171efa089ae26aba750d747d8149a4f860d5 Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Thu, 23 Apr 2009 13:58:07 +0200 Subject: [PATCH] [S390] appldata: avoid deadlock with appldata_mem The appldata_ops callbacks are called with a spin_lock held. But the appldata_mem callback then calls all_vm_events(), which calls get_online_cpus(), which might sleep. This possible deadlock is fixed by using a mutex instead of a spin_lock. Signed-off-by: Gerald Schaefer Signed-off-by: Martin Schwidefsky --- arch/s390/appldata/appldata_base.c | 32 ++++++++++++++++---------------- arch/s390/appldata/appldata_mem.c | 2 +- 2 files changed, 17 insertions(+), 17 deletions(-) diff --git a/arch/s390/appldata/appldata_base.c b/arch/s390/appldata/appldata_base.c index aeb3cff..1dfc710 100644 --- a/arch/s390/appldata/appldata_base.c +++ b/arch/s390/appldata/appldata_base.c @@ -98,7 +98,7 @@ static DECLARE_WORK(appldata_work, appldata_work_fn); /* * Ops list */ -static DEFINE_SPINLOCK(appldata_ops_lock); +static DEFINE_MUTEX(appldata_ops_mutex); static LIST_HEAD(appldata_ops_list); @@ -129,14 +129,14 @@ static void appldata_work_fn(struct work_struct *work) i = 0; get_online_cpus(); - spin_lock(&appldata_ops_lock); + mutex_lock(&appldata_ops_mutex); list_for_each(lh, &appldata_ops_list) { ops = list_entry(lh, struct appldata_ops, list); if (ops->active == 1) { ops->callback(ops->data); } } - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); put_online_cpus(); } @@ -338,7 +338,7 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp, struct list_head *lh; found = 0; - spin_lock(&appldata_ops_lock); + mutex_lock(&appldata_ops_mutex); list_for_each(lh, &appldata_ops_list) { tmp_ops = list_entry(lh, struct appldata_ops, list); if (&tmp_ops->ctl_table[2] == ctl) { @@ -346,15 +346,15 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp, } } if (!found) { - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); return -ENODEV; } ops = ctl->data; if (!try_module_get(ops->owner)) { // protect this function - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); return -ENODEV; } - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); if (!*lenp || *ppos) { *lenp = 0; @@ -378,11 +378,11 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp, return -EFAULT; } - spin_lock(&appldata_ops_lock); + mutex_lock(&appldata_ops_mutex); if ((buf[0] == '1') && (ops->active == 0)) { // protect work queue callback if (!try_module_get(ops->owner)) { - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); module_put(ops->owner); return -ENODEV; } @@ -407,7 +407,7 @@ appldata_generic_handler(ctl_table *ctl, int write, struct file *filp, "failed with rc=%d\n", ops->name, rc); module_put(ops->owner); } - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); out: *lenp = len; *ppos += len; @@ -433,9 +433,9 @@ int appldata_register_ops(struct appldata_ops *ops) if (!ops->ctl_table) return -ENOMEM; - spin_lock(&appldata_ops_lock); + mutex_lock(&appldata_ops_mutex); list_add(&ops->list, &appldata_ops_list); - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); ops->ctl_table[0].procname = appldata_proc_name; ops->ctl_table[0].maxlen = 0; @@ -452,9 +452,9 @@ int appldata_register_ops(struct appldata_ops *ops) goto out; return 0; out: - spin_lock(&appldata_ops_lock); + mutex_lock(&appldata_ops_mutex); list_del(&ops->list); - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); kfree(ops->ctl_table); return -ENOMEM; } @@ -466,9 +466,9 @@ out: */ void appldata_unregister_ops(struct appldata_ops *ops) { - spin_lock(&appldata_ops_lock); + mutex_lock(&appldata_ops_mutex); list_del(&ops->list); - spin_unlock(&appldata_ops_lock); + mutex_unlock(&appldata_ops_mutex); unregister_sysctl_table(ops->sysctl_header); kfree(ops->ctl_table); } diff --git a/arch/s390/appldata/appldata_mem.c b/arch/s390/appldata/appldata_mem.c index 3ed56b7..4188cbe 100644 --- a/arch/s390/appldata/appldata_mem.c +++ b/arch/s390/appldata/appldata_mem.c @@ -78,7 +78,7 @@ static void appldata_get_mem_data(void *data) { /* * don't put large structures on the stack, we are - * serialized through the appldata_ops_lock and can use static + * serialized through the appldata_ops_mutex and can use static */ static struct sysinfo val; unsigned long ev[NR_VM_EVENT_ITEMS]; -- 2.7.4