diff options
| author | Jakub Kicinski <[email protected]> | 2025-08-09 00:12:05 +0000 |
|---|---|---|
| committer | Paolo Abeni <[email protected]> | 2025-08-12 12:43:05 +0000 |
| commit | b3fc08ab9a565efb42fe08be046a0d203b82cdb8 (patch) | |
| tree | dc9a380c7e7a58f7e8e720d91efe752f933f6afa /net/core/dev.c | |
| parent | net: update NAPI threaded config even for disabled NAPIs (diff) | |
| download | kernel-b3fc08ab9a565efb42fe08be046a0d203b82cdb8.tar.gz kernel-b3fc08ab9a565efb42fe08be046a0d203b82cdb8.zip | |
net: prevent deadlocks when enabling NAPIs with mixed kthread config
The following order of calls currently deadlocks if:
- device has threaded=1; and
- NAPI has persistent config with threaded=0.
netif_napi_add_weight_config()
dev->threaded == 1
napi_kthread_create()
napi_enable()
napi_restore_config()
napi_set_threaded(0)
napi_stop_kthread()
while (NAPIF_STATE_SCHED)
msleep(20)
We deadlock because disabled NAPI has STATE_SCHED set.
Creating a thread in netif_napi_add() just to destroy it in
napi_disable() is fairly ugly in the first place. Let's read
both the device config and the NAPI config in netif_napi_add().
Fixes: e6d76268813d ("net: Update threaded state in napi config in netif_set_threaded")
Signed-off-by: Jakub Kicinski <[email protected]>
Reviewed-by: Joe Damato <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index f180746382a1..5a3c0f40a93f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -7357,8 +7357,9 @@ void netif_napi_add_weight_locked(struct net_device *dev, * Clear dev->threaded if kthread creation failed so that * threaded mode will not be enabled in napi_enable(). */ - if (dev->threaded && napi_kthread_create(napi)) - dev->threaded = NETDEV_NAPI_THREADED_DISABLED; + if (napi_get_threaded_config(dev, napi)) + if (napi_kthread_create(napi)) + dev->threaded = NETDEV_NAPI_THREADED_DISABLED; netif_napi_set_irq_locked(napi, -1); } EXPORT_SYMBOL(netif_napi_add_weight_locked); |