| Message ID | 20240314021010.1923729-1-i@liuyulong.me |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [ovs-dev] ofproto-dpif-upcall: try lock for umap iteration during sweep | expand |
| Context | Check | Description |
|---|---|---|
| ovsrobot/apply-robot | warning | apply and check: warning |
| ovsrobot/github-robot-_Build_and_Test | success | github build: passed |
| ovsrobot/intel-ovs-compilation | success | test: success |
Bleep bloop. Greetings LIU Yulong, I am a robot and I have tried out your patch. Thanks for your contribution. I encountered some error that I wasn't expecting. See the details below. checkpatch: WARNING: The subject summary should start with a capital. WARNING: The subject summary should end with a dot. Subject: ofproto-dpif-upcall: try lock for umap iteration during sweep Lines checked: 63, Warnings: 2, Errors: 0 Please check this out. If you feel there has been an error, please email aconole@redhat.com Thanks, 0-day Robot
diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c index 9a5c5c29c..ef13f820a 100644 --- a/ofproto/ofproto-dpif-upcall.c +++ b/ofproto/ofproto-dpif-upcall.c @@ -2974,6 +2974,10 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) struct umap *umap = &udpif->ukeys[i]; size_t n_ops = 0; + if (ovs_mutex_trylock(&umap->mutex)) { + continue; + } + CMAP_FOR_EACH(ukey, cmap_node, &umap->cmap) { enum ukey_state ukey_state; @@ -3013,9 +3017,7 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) if (ukey_state == UKEY_EVICTED) { /* The common flow deletion case involves deletion of the flow * during the dump phase and ukey deletion here. */ - ovs_mutex_lock(&umap->mutex); ukey_delete(umap, ukey); - ovs_mutex_unlock(&umap->mutex); } if (n_ops == REVALIDATE_MAX_BATCH) { @@ -3025,6 +3027,7 @@ revalidator_sweep__(struct revalidator *revalidator, bool purge) n_ops = 0; } } + ovs_mutex_unlock(&umap->mutex); if (n_ops) { push_ukey_ops(udpif, umap, ops, n_ops);
A potential race condition happened with the following 3 threads: * PMD thread replaced the old_ukey and transitioned the state to UKEY_DELETED. * RCU thread is freeing the old_ukey mutex. * While the revalidator thread is trying to lock the old_ukey mutex. Then vswitchd process aborts at the revalidator thread try_lock of ukey->mutex because of the NULL pointer. This patch adds the try_lock for the ukeys' basket umap to avoid the PMD and revalidator access to the same umap for replacing the ukey and transitioning the ukey state. More details can be found at: [1] https://mail.openvswitch.org/pipermail/ovs-discuss/2024-March/052973.html [2] https://mail.openvswitch.org/pipermail/ovs-discuss/2024-February/052949.html Signed-off-by: LIU Yulong <i@liuyulong.me> --- ofproto/ofproto-dpif-upcall.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)