为提高效率，提问时请提供以下信息，问题描述清晰可优先响应。
- 【TiDB 版本】：4.0
- 【问题描述】：
[tidb@tidbpd bin]$ ./br validate decode --field=“end-version” -s local:///data1/br_backupdir_nfs/20200922
Detial BR log in /tmp/br.log.2020-09-22T16.12.37+0800
419629597399711745
./br backup full --pd ${PDIP}:2379 -s local:///data1/br_backupdir_nfs/20200922_incr --lastbackupts 419629597399711745 --log-file /data1/br_backupdir_nfs/backup-nfs-incr.log
[2020/09/22 16:16:31.394 +08:00] [ERROR] [backup.go:154] [“Check gc safepoint for last backup ts failed”] [error=“GC safepoint 419630088880390144 exceed TS 419629597399711745”] [errorVerbose=“GC safepoint 419630088880390144 exceed TS 419
629597399711745\ngithub.com/pingcap/br/pkg/backup.CheckGCSafePoint\
\t/home/jenkins/agent/workspace/build_br_multi_branch_v4.0.0/go/src/github.com/pingcap/br/pkg/backup/safe_point.go:40\
github.com/pingcap/br/pkg/task.RunBackup\
\t/home/
jenkins/agent/workspace/build_br_multi_branch_v4.0.0/go/src/github.com/pingcap/br/pkg/task/backup.go:152\ngithub.com/pingcap/br/cmd.runBackupCommand\
\t/home/jenkins/agent/workspace/build_br_multi_branch_v4.0.0/go/src/github.com/pingcap/
br/cmd/backup.go:22\ngithub.com/pingcap/br/cmd.newFullBackupCommand.func1\
\t/home/jenkins/agent/workspace/build_br_multi_branch_v4.0.0/go/src/github.com/pingcap/br/cmd/backup.go:74\
github.com/spf13/cobra.(*Command).execute\
\t/go/pkg/m
od/github.com/spf13/cobra@v1.0.0/command.go:842\ngithub.com/spf13/cobra.(*Command).ExecuteC\
\t/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:950\ngithub.com/spf13/cobra.(*Command).Execute\
\t/go/pkg/mod/github.com/spf13/cobra@v1.0
.0/command.go:887\
main.main\
\t/home/jenkins/agent/workspace/build_br_multi_branch_v4.0.0/go/src/github.com/pingcap/br/main.go:54\
runtime.main\
\t/usr/local/go/src/runtime/proc.go:203\
runtime.goexit\
\t/usr/local/go/src/runtime/asm_am
d64.s:1357”] [stack=“github.com/pingcap/log.Error\
\t/go/pkg/mod/github.com/pingcap/log@v0.0.0-20200117041106-d28c14d3b1cd/global.go:42\
github.com/pingcap/br/pkg/task.RunBackup\
\t/home/jenkins/agent/workspace/build_br_multi_branch_v4.0
.0/go/src/github.com/pingcap/br/pkg/task/backup.go:154\ngithub.com/pingcap/br/cmd.runBackupCommand\
\t/home/jenkins/agent/workspace/build_br_multi_branch_v4.0.0/go/src/github.com/pingcap/br/cmd/backup.go:22\
github.com/pingcap/br/cmd.new
FullBackupCommand.func1\
\t/home/jenkins/agent/workspace/build_br_multi_branch_v4.0.0/go/src/github.com/pingcap/br/cmd/backup.go:74\ngithub.com/spf13/cobra.(*Command).execute\
\t/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:842\
g
ithub.com/spf13/cobra.(*Command).ExecuteC\
\t/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:950\ngithub.com/spf13/cobra.(*Command).Execute\
\t/go/pkg/mod/github.com/spf13/cobra@v1.0.0/command.go:887\
main.main\
\t/home/jenkins/agen
t/workspace/build_br_multi_branch_v4.0.0/go/src/github.com/pingcap/br/main.go:54\
runtime.main\
\t/usr/local/go/src/runtime/proc.go:203”]