diff --git a/internal/client/addrproc.go b/internal/client/addrproc.go
index 04ee50d5..2b8046f6 100644
--- a/internal/client/addrproc.go
+++ b/internal/client/addrproc.go
@@ -58,6 +58,12 @@ type DefaultAddrProcConfig struct {
 	// immediately by [NewDefaultAddrProc].
 	InitialAddresses []netip.Addr
 
+	// CatchPanics, if true, makes the address processor catch and log panics.
+	//
+	// TODO(a.garipov): Consider better ways to do this or apply this method to
+	// other parts of the codebase.
+	CatchPanics bool
+
 	// UseRDNS, if true, enables resolving of client IP addresses using reverse
 	// DNS.
 	UseRDNS bool
@@ -151,7 +157,7 @@ func NewDefaultAddrProc(c *DefaultAddrProcConfig) (p *DefaultAddrProc) {
 		p.whois = newWHOIS(c.DialContext)
 	}
 
-	go p.process()
+	go p.process(c.CatchPanics)
 
 	for _, ip := range c.InitialAddresses {
 		p.Process(ip)
@@ -214,8 +220,10 @@ func (p *DefaultAddrProc) Process(ip netip.Addr) {
 
 // process processes the incoming client IP-address information.  It is intended
 // to be used as a goroutine.  Once clientIPs is closed, process exits.
-func (p *DefaultAddrProc) process() {
-	defer log.OnPanic("addrProcessor.process")
+func (p *DefaultAddrProc) process(catchPanics bool) {
+	if catchPanics {
+		defer log.OnPanic("addrProcessor.process")
+	}
 
 	log.Info("clients: processing addresses")
 
diff --git a/internal/client/addrproc_test.go b/internal/client/addrproc_test.go
index c6b847cd..c6b38657 100644
--- a/internal/client/addrproc_test.go
+++ b/internal/client/addrproc_test.go
@@ -2,6 +2,7 @@ package client_test
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"net"
 	"net/netip"
@@ -112,6 +113,7 @@ func TestDefaultAddrProc_Process_rDNS(t *testing.T) {
 				AddressUpdater: &aghtest.AddressUpdater{
 					OnUpdateAddress: newOnUpdateAddress(tc.wantUpd, updIPCh, updHostCh, updInfoCh),
 				},
+				CatchPanics:    false,
 				UseRDNS:        true,
 				UsePrivateRDNS: tc.usePrivate,
 				UseWHOIS:       false,
@@ -146,8 +148,8 @@ func newOnUpdateAddress(
 	infos chan<- *whois.Info,
 ) (f func(ip netip.Addr, host string, info *whois.Info)) {
 	return func(ip netip.Addr, host string, info *whois.Info) {
-		if !want {
-			panic("got unexpected update")
+		if !want && (host != "" || info != nil) {
+			panic(fmt.Errorf("got unexpected update for %v with %q and %v", ip, host, info))
 		}
 
 		ips <- ip
@@ -222,6 +224,7 @@ func TestDefaultAddrProc_Process_WHOIS(t *testing.T) {
 				AddressUpdater: &aghtest.AddressUpdater{
 					OnUpdateAddress: newOnUpdateAddress(tc.wantUpd, updIPCh, updHostCh, updInfoCh),
 				},
+				CatchPanics:    false,
 				UseRDNS:        false,
 				UsePrivateRDNS: false,
 				UseWHOIS:       true,
diff --git a/internal/dnsforward/dnsforward_test.go b/internal/dnsforward/dnsforward_test.go
index a5e25681..e1927a65 100644
--- a/internal/dnsforward/dnsforward_test.go
+++ b/internal/dnsforward/dnsforward_test.go
@@ -72,13 +72,6 @@ func startDeferStop(t *testing.T, s *Server) {
 	testutil.CleanupAndRequireSuccess(t, s.Stop)
 }
 
-// packageUpstreamVariableMu is used to serialize access to the package-level
-// variables of package upstream.
-//
-// TODO(s.chzhen): Move these parameters to upstream options and remove this
-// crutch.
-var packageUpstreamVariableMu = &sync.Mutex{}
-
 func createTestServer(
 	t *testing.T,
 	filterConf *filtering.Config,
@@ -87,9 +80,6 @@ func createTestServer(
 ) (s *Server) {
 	t.Helper()
 
-	packageUpstreamVariableMu.Lock()
-	defer packageUpstreamVariableMu.Unlock()
-
 	rules := `||nxdomain.example.org
 ||NULL.example.org^
 127.0.0.1	host.example.org
diff --git a/internal/home/dns.go b/internal/home/dns.go
index 87cb70fd..cb6a5142 100644
--- a/internal/home/dns.go
+++ b/internal/home/dns.go
@@ -254,6 +254,7 @@ func newServerConfig(
 		Exchanger:        Context.dnsServer,
 		AddressUpdater:   &Context.clients,
 		InitialAddresses: initialAddresses,
+		CatchPanics:      true,
 		UseRDNS:          config.Clients.Sources.RDNS,
 		UseWHOIS:         config.Clients.Sources.WHOIS,
 	}