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([140.174.219.137]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8ca2fa8144csm20469185a.14.2026.02.03.10.04.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Feb 2026 10:04:44 -0800 (PST) From: Emil Tsalapatis To: bpf@vger.kernel.org Cc: andrii@kernel.org, ast@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, martin.lau@kernel.org, memxor@gmail.com, song@kernel.org, yonghong.song@linux.dev, Emil Tsalapatis Subject: [PATCH v2 3/4] bpf: Allow BPF stream kfuncs while holding a lock Date: Tue, 3 Feb 2026 13:04:23 -0500 Message-ID: <20260203180424.14057-4-emil@etsalapatis.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20260203180424.14057-1-emil@etsalapatis.com> References: <20260203180424.14057-1-emil@etsalapatis.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The BPF stream kfuncs bpf_stream_vprintk and bpf_stream_print_stack do not sleep and so are safe to call while holding a lock. Amend the verifier to allow that. Signed-off-by: Emil Tsalapatis Acked-by: Kumar Kartikeya Dwivedi --- kernel/bpf/verifier.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6b62b6d57175..90811fb39974 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -12438,6 +12438,8 @@ enum special_kfunc_type { KF_bpf_arena_free_pages, KF_bpf_arena_reserve_pages, KF_bpf_session_is_return, + KF_bpf_stream_vprintk, + KF_bpf_stream_print_stack, }; BTF_ID_LIST(special_kfunc_list) @@ -12516,6 +12518,8 @@ BTF_ID(func, bpf_arena_alloc_pages) BTF_ID(func, bpf_arena_free_pages) BTF_ID(func, bpf_arena_reserve_pages) BTF_ID(func, bpf_session_is_return) +BTF_ID(func, bpf_stream_vprintk) +BTF_ID(func, bpf_stream_print_stack) static bool is_task_work_add_kfunc(u32 func_id) { @@ -12960,10 +12964,17 @@ static bool is_bpf_arena_kfunc(u32 btf_id) btf_id == special_kfunc_list[KF_bpf_arena_reserve_pages]; } +static bool is_bpf_stream_kfunc(u32 btf_id) +{ + return btf_id == special_kfunc_list[KF_bpf_stream_vprintk] || + btf_id == special_kfunc_list[KF_bpf_stream_print_stack]; +} + static bool kfunc_spin_allowed(u32 btf_id) { return is_bpf_graph_api_kfunc(btf_id) || is_bpf_iter_num_api_kfunc(btf_id) || - is_bpf_res_spin_lock_kfunc(btf_id) || is_bpf_arena_kfunc(btf_id); + is_bpf_res_spin_lock_kfunc(btf_id) || is_bpf_arena_kfunc(btf_id) || + is_bpf_stream_kfunc(btf_id); } static bool is_sync_callback_calling_kfunc(u32 btf_id) -- 2.49.0