When creating a large perf map, a null pointer error is encountered

[cfc4n]

Describe the bug

Use perf.NewReader to create an ebpf map. If the perCPUBuffer exceeds the threshold of the kernel, creation will fail and a null pointer error will occur.

error logs:

root@vm-server:/home/cfc4n/project/ecapture# bin/ecapture tls --mapsize=409600
tls_2023/12/22 11:43:59 ECAPTURE :: ecapture Version : linux_x86_64:--:[CORE]
tls_2023/12/22 11:43:59 ECAPTURE :: Pid Info : 14867
tls_2023/12/22 11:43:59 ECAPTURE :: Kernel Info : 5.15.131
tls_2023/12/22 11:43:59 cmd tls.go: mapSizeKB:1638400
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	module initialization
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	master key keylogger:
tls_2023/12/22 11:43:59 ECAPTURE ::	Module.Run()
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	Text MODEL
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	OpenSSL/BoringSSL version not found from shared library file, used default version:linux_default_3_0
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	HOOK type:2, binrayPath:/lib/x86_64-linux-gnu/libssl.so.3
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	Hook masterKey function:SSL_write
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	libPthread:/lib/x86_64-linux-gnu/libc.so.6
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	target all process.
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	target all users.
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	BPF bytecode filename:user/bytecode/openssl_3_0_0_kern.o
tls_2023/12/22 11:43:59 EBPFProbeOPENSSL	perfEventReader created. mapSize:1600 MB
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x6e22e5]

goroutine 1 [running]:
github.com/cilium/ebpf/perf.NewReaderWithOptions(0xc000073680, 0x64000000, {0x97481c?, 0x70?})
	/home/cfc4n/gopath/pkg/mod/github.com/cilium/ebpf@v0.12.3/perf/reader.go:234 +0x345
github.com/cilium/ebpf/perf.NewReader(...)
	/home/cfc4n/gopath/pkg/mod/github.com/cilium/ebpf@v0.12.3/perf/reader.go:187
ecapture/user/module.(*Module).perfEventReader(0xc0000d8580, 0xc0022fc960, 0xc000073680)
	/home/cfc4n/project/ecapture/user/module/imodule.go:193 +0x1b5
ecapture/user/module.(*Module).readEvents(0xc0000d8580)
	/home/cfc4n/project/ecapture/user/module/imodule.go:181 +0x114
ecapture/user/module.(*Module).Run(0xc0000d8580)
	/home/cfc4n/project/ecapture/user/module/imodule.go:140 +0x10f
ecapture/cli/cmd.openSSLCommandFunc(0xc0000b1100?, {0x9748d4?, 0x4?, 0x974818?})
	/home/cfc4n/project/ecapture/cli/cmd/tls.go:132 +0xa50
github.com/spf13/cobra.(*Command).execute(0x1372ae0, {0xc000082cd0, 0x1, 0x1})
	/home/cfc4n/gopath/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:860 +0x67b
github.com/spf13/cobra.(*Command).ExecuteC(0x1372860)
	/home/cfc4n/gopath/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:974 +0x38d
github.com/spf13/cobra.(*Command).Execute(...)
	/home/cfc4n/gopath/pkg/mod/github.com/spf13/cobra@v1.4.0/command.go:902
ecapture/cli/cmd.Execute()
	/home/cfc4n/project/ecapture/cli/cmd/root.go:75 +0x10b
ecapture/cli.Start(...)
	/home/cfc4n/project/ecapture/cli/main.go:22
main.main()
	/home/cfc4n/project/ecapture/main.go:73 +0x28e

ref: eCapture run failed, error log: invalid memory address or nil pointer dereference

How to reproduce

var perCpuSize int = 4096 * 1024 * 1024 // 4GB
	events, err := ebpf.NewMap(&ebpf.MapSpec{
		Type: ebpf.PerfEventArray,
	})
	if err != nil {
		log.Fatal(err)
	}
	
	rd, err := NewReader(events, perCpuSize)
	if err != nil {
		log.Fatal(err)
	}

Version information

github.com/cilium/ebpf v0.12.3

Tasks

Beta Give feedback

1. perf: fix nil pointer when perf map create failed #1282
   +0