经确认为gitea本身程序出错，正在向gitea官方反馈：

# /usr/sbin/gitea web -c /etc/gitea/gitea.ini --pid /var/run/gitea/gitea.pid
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x7c4fb3]

goroutine 1 [running]:
code.gitea.io/gitea/vendor/gopkg.in/ini%2ev1.(*Key).transformValue(0xc4205d1f20, 0xc4205bf651, 0x28, 0xc42058ee38, 0x4b0a09)
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/vendor/gopkg.in/ini.v1/key.go:123 +0xa3
code.gitea.io/gitea/vendor/gopkg.in/ini%2ev1.(*Key).String(0xc4205d1f20, 0xc4205d2a60, 0x15)
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/vendor/gopkg.in/ini.v1/key.go:130 +0x3d
code.gitea.io/gitea/vendor/gopkg.in/ini%2ev1.(*Key).MustString(0xc4205d1f20, 0xc4205d2a60, 0x15, 0x1, 0xc4205d2a60)
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/vendor/gopkg.in/ini.v1/key.go:202 +0x2f
code.gitea.io/gitea/modules/setting.NewContext()
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/modules/setting/setting.go:1151 +0x4584
code.gitea.io/gitea/routers.GlobalInit()
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/routers/init.go:47 +0x4a
code.gitea.io/gitea/cmd.runWeb(0xc420222b40, 0x0, 0x0)
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/cmd/web.go:83 +0xa8
code.gitea.io/gitea/vendor/github.com/urfave/cli.HandleAction(0x162ff20, 0x1929dd8, 0xc420222b40, 0xc420579500, 0x0)
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/vendor/github.com/urfave/cli/app.go:471 +0xad
code.gitea.io/gitea/vendor/github.com/urfave/cli.Command.Run(0x186e11c, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1898f49, 0x16, 0x0, ...)
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/vendor/github.com/urfave/cli/command.go:191 +0xa0e
code.gitea.io/gitea/vendor/github.com/urfave/cli.(*App).Run(0xc420501d40, 0xc42003a0c0, 0x6, 0x6, 0x0, 0x0)
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/vendor/github.com/urfave/cli/app.go:241 +0x5b8
main.main()
        /home/rpmbuild/rpmbuild/BUILD/_gobuild/src/code.gitea.io/gitea/main.go:52 +0x40e

参考：https://github.com/go-gitea/gitea/issues/4260

将配置文件 /etc/gitea/gitea.ini 中下面这段：

[U2F]
; Two Factor authentication with security keys
; https://developers.yubico.com/U2F/App_ID.html
APP_ID         = "%(PROTOCOL)s://%(DOMAIN)s:%(HTTP_PORT)s/"
; Comma seperated list of truisted facets
TRUSTED_FACETS = "%(PROTOCOL)s://%(DOMAIN)s:%(HTTP_PORT)s/"

改为下面这样即可（即注释掉APP_ID和TRUSTED_FACETS这两行）：

[U2F]
; Two Factor authentication with security keys
; https://developers.yubico.com/U2F/App_ID.html
;APP_ID         = "%(PROTOCOL)s://%(DOMAIN)s:%(HTTP_PORT)s/"
; Comma seperated list of truisted facets
;TRUSTED_FACETS = "%(PROTOCOL)s://%(DOMAIN)s:%(HTTP_PORT)s/"