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Fix EBUSY errors from netlink operations.
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Hunch is that the change in vishvananda/netlink#1018,
will prevent EBUSY by draining the remaining messages from the kernel
before returning.

Before vishvananda/netlink#925, all messages
would be read but the "interrupted" flag was ignored.  That PR made it
so that the dump would return early, but that would leave some messages
unconsumed.  There was logic elsewhere to discard these messages,
but the kernel has a check for "dump in progress" at the start of a new
dump and it returns EBUSY in that case:

```
int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
			 const struct nlmsghdr *nlh,
			 struct netlink_dump_control *control)
{
...
	mutex_lock(&nlk->nl_cb_mutex);
	/* A dump is in progress... */
	if (nlk->cb_running) {
		ret = -EBUSY;
		goto error_unlock;
	}
```

I wasn't able to trace the exact path through the kernel code to verify
when cb_running would be set, or that the error would be returned
on the NLMSG_DONE as we see here but it seemed like a solid bet.
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@fasaxc
fasaxc committed Jan 29, 2025
1 parent 2348ecf commit c25cfe2
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Showing 3 changed files with 23 additions and 18 deletions.
20 changes: 16 additions & 4 deletions felix/ifacemonitor/iface_monitor.go
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Original file line number Diff line number Diff line change
Expand Up @@ -411,10 +411,22 @@ func (m *InterfaceMonitor) storeAndNotifyLinkInner(ifaceExists bool, ifaceName s

func (m *InterfaceMonitor) resync() error {
log.Debug("Resyncing interface state.")
links, err := m.netlinkStub.LinkList()
if err != nil {
log.WithError(err).Warn("Netlink list operation failed.")
return err
// we need to retry when the error returned is EINTR.
var links []netlink.Link
var err error
retries := 3
for {
links, err = m.netlinkStub.LinkList()
if err != nil {
if errors.Is(err, syscall.EINTR) && retries > 0 {
log.WithError(err).Warn("Netlink list operation failed. Retrying")
retries--
continue
}
log.WithError(err).Warn("Netlink list operation failed.")
return err
}
break
}
currentIfaces := set.New[string]()
for _, link := range links {
Expand Down
7 changes: 3 additions & 4 deletions go.mod
View file
Original file line number Diff line number Diff line change
Expand Up @@ -46,7 +46,6 @@ require (
github.com/kardianos/osext v0.0.0-20190222173326-2bc1f35cddc0
github.com/kelseyhightower/envconfig v1.4.0
github.com/kelseyhightower/memkv v0.1.1
github.com/lestrrat-go/file-rotatelogs v2.4.0+incompatible
github.com/libp2p/go-reuseport v0.4.0
github.com/mcuadros/go-version v0.0.0-20190830083331-035f6764e8d2
github.com/mipearson/rfw v0.0.0-20170619235010-6f0a6f3266ba
Expand Down Expand Up @@ -77,7 +76,7 @@ require (
github.com/tchap/go-patricia/v2 v2.3.1
github.com/termie/go-shutil v0.0.0-20140729215957-bcacb06fecae
github.com/urfave/cli/v2 v2.27.5
github.com/vishvananda/netlink v1.3.0
github.com/vishvananda/netlink v1.3.1-0.20250128002108-7c2350bd140f
go.etcd.io/etcd/api/v3 v3.5.17
go.etcd.io/etcd/client/pkg/v3 v3.5.17
go.etcd.io/etcd/client/v2 v2.305.17
Expand Down Expand Up @@ -114,6 +113,8 @@ require (
sigs.k8s.io/yaml v1.4.0
)

require golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56

require (
filippo.io/edwards25519 v1.1.0 // indirect
github.com/JeffAshton/win_pdh v0.0.0-20161109143554-76bb4ee9f0ab // indirect
Expand Down Expand Up @@ -234,7 +235,6 @@ require (
github.com/klauspost/compress v1.17.11 // indirect
github.com/kylelemons/godebug v1.1.0 // indirect
github.com/leodido/go-urn v0.0.0-20181204092800-a67a23e1c1af // indirect
github.com/lestrrat-go/strftime v1.1.0 // indirect
github.com/libopenstorage/openstorage v1.0.0 // indirect
github.com/lithammer/dedent v1.1.0 // indirect
github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
Expand Down Expand Up @@ -308,7 +308,6 @@ require (
go.opentelemetry.io/proto/otlp v1.3.1 // indirect
go.uber.org/multierr v1.11.0 // indirect
go.uber.org/zap v1.26.0 // indirect
golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 // indirect
golang.org/x/net v0.33.0 // indirect
golang.org/x/oauth2 v0.24.0 // indirect
golang.org/x/term v0.27.0 // indirect
Expand Down
14 changes: 4 additions & 10 deletions go.sum
View file
Original file line number Diff line number Diff line change
Expand Up @@ -219,10 +219,10 @@ github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMo
github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
github.com/fsnotify/fsnotify v1.8.0 h1:dAwr6QBTBZIkG8roQaJjGof0pp0EeF+tNV7YBP3F/8M=
github.com/fsnotify/fsnotify v1.8.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
github.com/gavv/monotime v0.0.0-20190418164738-30dba4353424 h1:Vh7rylVZRZCj6W41lRlP17xPk4Nq260H4Xo/DDYmEZk=
github.com/gavv/monotime v0.0.0-20190418164738-30dba4353424/go.mod h1:vmp8DIyckQMXOPl0AQVHt+7n5h7Gb7hS6CUydiV8QeA=
github.com/fxamacker/cbor/v2 v2.7.0 h1:iM5WgngdRBanHcxugY4JySA0nk1wZorNOpTgCMedv5E=
github.com/fxamacker/cbor/v2 v2.7.0/go.mod h1:pxXPTn3joSm21Gbwsv0w9OSA2y1HFR9qXEeXQVeNoDQ=
github.com/gavv/monotime v0.0.0-20190418164738-30dba4353424 h1:Vh7rylVZRZCj6W41lRlP17xPk4Nq260H4Xo/DDYmEZk=
github.com/gavv/monotime v0.0.0-20190418164738-30dba4353424/go.mod h1:vmp8DIyckQMXOPl0AQVHt+7n5h7Gb7hS6CUydiV8QeA=
github.com/ghodss/yaml v1.0.0 h1:wQHKEahhL6wmXdzwWG11gIVCkOv05bNOh+Rxn0yngAk=
github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeMEF04=
github.com/go-errors/errors v1.0.1/go.mod h1:f4zRHt4oKfwPJE5k8C9vpYG+aDHdBFUsgrm6/TyX73Q=
Expand Down Expand Up @@ -444,12 +444,6 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
github.com/leodido/go-urn v0.0.0-20181204092800-a67a23e1c1af h1:EhEGUQX36JFkvSWzrwGjjTJxrx7atfJdxv8cxFzmaB0=
github.com/leodido/go-urn v0.0.0-20181204092800-a67a23e1c1af/go.mod h1:+cyI34gQWZcE1eQU7NVgKkkzdXDQHr1dBMtdAPozLkw=
github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc h1:RKf14vYWi2ttpEmkA4aQ3j4u9dStX2t4M8UM6qqNsG8=
github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc/go.mod h1:kopuH9ugFRkIXf3YoqHKyrJ9YfUFsckUU9S7B+XP+is=
github.com/lestrrat-go/file-rotatelogs v2.4.0+incompatible h1:Y6sqxHMyB1D2YSzWkLibYKgg+SwmyFU9dF2hn6MdTj4=
github.com/lestrrat-go/file-rotatelogs v2.4.0+incompatible/go.mod h1:ZQnN8lSECaebrkQytbHj4xNgtg8CR7RYXnPok8e0EHA=
github.com/lestrrat-go/strftime v1.1.0 h1:gMESpZy44/4pXLO/m+sL0yBd1W6LjgjrrD4a68Gapyg=
github.com/lestrrat-go/strftime v1.1.0/go.mod h1:uzeIB52CeUJenCo1syghlugshMysrqUT51HlxphXVeI=
github.com/libopenstorage/openstorage v1.0.0 h1:GLPam7/0mpdP8ZZtKjbfcXJBTIA/T1O6CBErVEFEyIM=
github.com/libopenstorage/openstorage v1.0.0/go.mod h1:Sp1sIObHjat1BeXhfMqLZ14wnOzEhNx2YQedreMcUyc=
github.com/libp2p/go-reuseport v0.4.0 h1:nR5KU7hD0WxXCJbmw7r2rhRYruNRl2koHw8fQscQm2s=
Expand Down Expand Up @@ -672,8 +666,8 @@ github.com/urfave/cli/v2 v2.27.5 h1:WoHEJLdsXr6dDWoJgMq/CboDmyY/8HMMH1fTECbih+w=
github.com/urfave/cli/v2 v2.27.5/go.mod h1:3Sevf16NykTbInEnD0yKkjDAeZDS0A6bzhBH5hrMvTQ=
github.com/virtuald/go-ordered-json v0.0.0-20170621173500-b18e6e673d74 h1:JwtAtbp7r/7QSyGz8mKUbYJBg2+6Cd7OjM8o/GNOcVo=
github.com/virtuald/go-ordered-json v0.0.0-20170621173500-b18e6e673d74/go.mod h1:RmMWU37GKR2s6pgrIEB4ixgpVCt/cf7dnJv3fuH1J1c=
github.com/vishvananda/netlink v1.3.0 h1:X7l42GfcV4S6E4vHTsw48qbrV+9PVojNfIhZcwQdrZk=
github.com/vishvananda/netlink v1.3.0/go.mod h1:i6NetklAujEcC6fK0JPjT8qSwWyO0HLn4UKG+hGqeJs=
github.com/vishvananda/netlink v1.3.1-0.20250128002108-7c2350bd140f h1:G5t3qYQ3YL2zMn2kFzRYIPk1EvDvMNV9pP+w+39VtzI=
github.com/vishvananda/netlink v1.3.1-0.20250128002108-7c2350bd140f/go.mod h1:i6NetklAujEcC6fK0JPjT8qSwWyO0HLn4UKG+hGqeJs=
github.com/vishvananda/netns v0.0.4 h1:Oeaw1EM2JMxD51g9uhtC0D7erkIjgmj8+JZc26m1YX8=
github.com/vishvananda/netns v0.0.4/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZlaprSwhNNJM=
github.com/x448/float16 v0.8.4 h1:qLwI1I70+NjRFUR3zs1JPUCgaCXSh3SW62uAKT1mSBM=
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