how break point work in multi-thread multi-core linux?

[xie cui]

as for as i known, in linux, seting a breakpoint means we set int 3 instruction to the right place, it's easy to understand in single core os for me. but what happen when it's multi-core multi-thread enviroment like go program. using goland when set a breakpoint, when the breakpoint hit, it seems all the thread of the process is pause, how delve stop other thread that no run to the breakpoint, i am confused.

[Marcin Romaszewicz]

Threads are scheduled by the operating system, which has many syscalls to manage their execution status. When Delve hits an interrupt (trap) instruction for a breakpoint, it asks the OS to suspend all the other OS threads. Goroutine thread stacks are managed by Go, and Delve inspects all those stacks to show you goroutines. So, when a goroutine hits a breakpoint, its underlying OS thread hits a trap, and in this trap handler, all the other OS threads are stopped, see here for example:

https://github.com/go-delve/delve/blob/master/pkg/proc/native/proc_linux.go#L546

-- Marcin

On Wed, Jun 9, 2021 at 6:48 AM xie cui <cuiw...@gmail.com> wrote:

as for as i known, in linux, seting a breakpoint means we set int 3 instruction to the right place, it's easy to understand in single core os for me. but what happen when it's multi-core multi-thread enviroment like go program. using goland when set a breakpoint, when the breakpoint hit, it seems all the thread of the process is pause, how delve stop other thread that no run to the breakpoint, i am confused.

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