From: Johannes Berg <johannes@sipsolutions.net>
To: linux-wireless@vger.kernel.org
Cc: Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH v2] rfkill: sync before userspace visibility/changes
Date: Thu, 14 Sep 2023 15:36:05 +0200 [thread overview]
Message-ID: <20230914153604.9d1ce0f43ac8.If977317d8f6a0f557090defcd6aef67628f62ff7@changeid> (raw)
From: Johannes Berg <johannes.berg@intel.com>
If userspace quickly opens /dev/rfkill after a new
instance was created, it might see the old state of
the instance from before the sync work runs and may
even _change_ the state, only to have the sync work
change it again.
Fix this by doing the sync inline where needed, not
just for /dev/rfkill but also for sysfs.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
v2: add lockdep assert
---
net/rfkill/core.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)
diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 01fca7a10b4b..2768decb6cda 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c
@@ -48,6 +48,7 @@ struct rfkill {
bool persistent;
bool polling_paused;
bool suspended;
+ bool need_sync;
const struct rfkill_ops *ops;
void *data;
@@ -730,6 +731,10 @@ static ssize_t soft_show(struct device *dev, struct device_attribute *attr,
{
struct rfkill *rfkill = to_rfkill(dev);
+ mutex_lock(&rfkill_global_mutex);
+ rfkill_sync(rfkill);
+ mutex_unlock(&rfkill_global_mutex);
+
return sysfs_emit(buf, "%d\n", (rfkill->state & RFKILL_BLOCK_SW) ? 1 : 0);
}
@@ -751,6 +756,7 @@ static ssize_t soft_store(struct device *dev, struct device_attribute *attr,
return -EINVAL;
mutex_lock(&rfkill_global_mutex);
+ rfkill_sync(rfkill);
rfkill_set_block(rfkill, state);
mutex_unlock(&rfkill_global_mutex);
@@ -783,6 +789,10 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
{
struct rfkill *rfkill = to_rfkill(dev);
+ mutex_lock(&rfkill_global_mutex);
+ rfkill_sync(rfkill);
+ mutex_unlock(&rfkill_global_mutex);
+
return sysfs_emit(buf, "%d\n", user_state_from_blocked(rfkill->state));
}
@@ -805,6 +815,7 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
return -EINVAL;
mutex_lock(&rfkill_global_mutex);
+ rfkill_sync(rfkill);
rfkill_set_block(rfkill, state == RFKILL_USER_STATE_SOFT_BLOCKED);
mutex_unlock(&rfkill_global_mutex);
@@ -1030,16 +1041,23 @@ static void rfkill_uevent_work(struct work_struct *work)
mutex_unlock(&rfkill_global_mutex);
}
+static void rfkill_sync(struct rfkill *rfkill)
+{
+ lockdep_assert_held(&rfkill_global_mutex);
+
+ if (!rfkill->need_sync)
+ return;
+
+ rfkill_set_block(rfkill, rfkill_global_states[rfkill->type].cur);
+ rfkill->need_sync = false;
+}
+
static void rfkill_sync_work(struct work_struct *work)
{
- struct rfkill *rfkill;
- bool cur;
-
- rfkill = container_of(work, struct rfkill, sync_work);
+ struct rfkill *rfkill = container_of(work, struct rfkill, sync_work);
mutex_lock(&rfkill_global_mutex);
- cur = rfkill_global_states[rfkill->type].cur;
- rfkill_set_block(rfkill, cur);
+ rfkill_sync(rfkill);
mutex_unlock(&rfkill_global_mutex);
}
@@ -1087,6 +1105,7 @@ int __must_check rfkill_register(struct rfkill *rfkill)
round_jiffies_relative(POLL_INTERVAL));
if (!rfkill->persistent || rfkill_epo_lock_active) {
+ rfkill->need_sync = true;
schedule_work(&rfkill->sync_work);
} else {
#ifdef CONFIG_RFKILL_INPUT
@@ -1171,6 +1190,7 @@ static int rfkill_fop_open(struct inode *inode, struct file *file)
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
if (!ev)
goto free;
+ rfkill_sync(rfkill);
rfkill_fill_event(&ev->ev, rfkill, RFKILL_OP_ADD);
list_add_tail(&ev->list, &data->events);
}
--
2.41.0
next reply other threads:[~2023-09-14 13:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-14 13:36 Johannes Berg [this message]
2023-09-14 18:47 ` [PATCH v2] rfkill: sync before userspace visibility/changes kernel test robot
2023-09-14 23:34 ` kernel test robot
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