Commit 63328bb2 authored by Emil Tsalapatis's avatar Emil Tsalapatis Committed by Alexei Starovoitov
Browse files

bpf: Add bpf_stream_print_stack stack dumping kfunc 



Add a new kfunc called bpf_stream_print_stack to be used by programs
that need to print out their current BPF stack. The kfunc is essentially
a wrapper around the existing bpf_stream_dump_stack functionality used
to generate stack traces for error events like may_goto violations and
BPF-side arena page faults.

Signed-off-by: default avatarEmil Tsalapatis <emil@etsalapatis.com>
Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260203180424.14057-2-emil@etsalapatis.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f941479a

kernel/bpf/helpers.c

+1 −0
Original line number Diff line number Diff line
@@ -4562,6 +4562,7 @@ BTF_ID_FLAGS(func, bpf_strncasestr); 
BTF_ID_FLAGS(func, bpf_cgroup_read_xattr, KF_RCU)

#endif

BTF_ID_FLAGS(func, bpf_stream_vprintk, KF_IMPLICIT_ARGS)

BTF_ID_FLAGS(func, bpf_stream_print_stack, KF_IMPLICIT_ARGS)

BTF_ID_FLAGS(func, bpf_task_work_schedule_signal, KF_IMPLICIT_ARGS)

BTF_ID_FLAGS(func, bpf_task_work_schedule_resume, KF_IMPLICIT_ARGS)

BTF_ID_FLAGS(func, bpf_dynptr_from_file)

kernel/bpf/stream.c

+19 −0
Original line number Diff line number Diff line
@@ -245,6 +245,25 @@ __bpf_kfunc int bpf_stream_vprintk(int stream_id, const char *fmt__str, const vo 
	return ret;

}



/* Directly trigger a stack dump from the program. */

__bpf_kfunc int bpf_stream_print_stack(int stream_id, struct bpf_prog_aux *aux)

{

	struct bpf_stream_stage ss;

	struct bpf_prog *prog;



	/* Make sure the stream ID is valid. */

	if (!bpf_stream_get(stream_id, aux))

		return -ENOENT;



	prog = aux->main_prog_aux->prog;



	bpf_stream_stage(ss, prog, stream_id, ({

		bpf_stream_dump_stack(ss);

	}));



	return 0;

}



__bpf_kfunc_end_defs();



/* Added kfunc to common_btf_ids */