From nobody Thu Nov 28 22:42:51 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 610BC1798F; Thu, 26 Sep 2024 11:53:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727351630; cv=none; b=qFf76vbphVxiPh+R0aEBU2MFYLj30E5KOYNt6ZGHghE6uFMfkHkGCJ+7IDPn2o9eekdsqADz3jVP++OTMmD7o9UakqnRtDvzv7UMTc3UVGKiazQXCHGdwWI4Z5Rd/9IjsXlNcMkf/EPge2RNle4Fy2tTWBoKIuiLhN9M30JNkH4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727351630; c=relaxed/simple; bh=2WVwb/Rv5Uv37R0eDSMuZzkbHgeTyCNWtZJ35FWrJeo=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=FzQC9VtInfmmKdlq/eabPyxnJ956VTljy4Z+YcQx/7Fgi4Uc8xmGNzAl1t2WW7vOL7GxJP2acp7czJwiPjNRYO/3stAzzARDiq2s1bcB8MbwAsSECPzHSb5cXN7Q3roRelJ+Sfo1jvFXpWLHyRxGSad1P4EoOeHadHYC6SMFfVw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Co2A07VR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Co2A07VR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A491BC4CEC9; Thu, 26 Sep 2024 11:53:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727351629; bh=2WVwb/Rv5Uv37R0eDSMuZzkbHgeTyCNWtZJ35FWrJeo=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Co2A07VRLi0ocLBpYplZWldH4eiLkBVrb0kBvKBfRQtRWTqQrHo5jUD2tQlMQIwkz DC5iJ0Sx6vkm54Bq7H58EPVn62oSi9ZG9UYe3pcBCqpxg0XWO6UpU5AAExpbmVM8yA JWbqo0fcvmKXC7gV7R/6W4TZEk4/HrOmFAkMO2KTi4Nz/2igpaO7f7s3CXCeQIeIuV jpI6X44oz/fGrLLqK+HBkK2uyqt7gUUnQa0nVn7fsv+zKbUAzVJFcBrtyBmLdpZ4f6 krnPO0t+5kWhoawDr+FvmbZoKByMtKVR97HB+pnxag83V98vUR/XKhRUETpVyr8idh 4jCvY9grFWcZQ== From: Puranjay Mohan To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, puranjay12@gmail.com Subject: [PATCH bpf-next v2 1/2] bpf: implement bpf_send_signal_remote() kfunc Date: Thu, 26 Sep 2024 11:53:27 +0000 Message-Id: <20240926115328.105634-2-puranjay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240926115328.105634-1-puranjay@kernel.org> References: <20240926115328.105634-1-puranjay@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Implement bpf_send_signal_remote kfunc that is similar to bpf_send_signal_thread and bpf_send_signal helpers but can be used to send signals to other threads and processes. It also supports sending a cookie with the signal similar to sigqueue(). If the receiving process establishes a handler for the signal using the SA_SIGINFO flag to sigaction(), then it can obtain this cookie via the si_value field of the siginfo_t structure passed as the second argument to the handler. Signed-off-by: Puranjay Mohan --- kernel/trace/bpf_trace.c | 78 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 77 insertions(+), 1 deletion(-) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index a582cd25ca876..51b27db1321fc 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -802,6 +802,9 @@ struct send_signal_irq_work { struct task_struct *task; u32 sig; enum pid_type type; + bool is_siginfo; + kernel_siginfo_t info; + int value; }; =20 static DEFINE_PER_CPU(struct send_signal_irq_work, send_signal_work); @@ -811,7 +814,11 @@ static void do_bpf_send_signal(struct irq_work *entry) struct send_signal_irq_work *work; =20 work =3D container_of(entry, struct send_signal_irq_work, irq_work); - group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, work->type); + if (work->is_siginfo) + group_send_sig_info(work->sig, &work->info, work->task, work->type); + else + group_send_sig_info(work->sig, SEND_SIG_PRIV, work->task, work->type); + put_task_struct(work->task); } =20 @@ -848,6 +855,7 @@ static int bpf_send_signal_common(u32 sig, enum pid_typ= e type) * irq works get executed. */ work->task =3D get_task_struct(current); + work->is_siginfo =3D false; work->sig =3D sig; work->type =3D type; irq_work_queue(&work->irq_work); @@ -3484,3 +3492,71 @@ static int __init bpf_kprobe_multi_kfuncs_init(void) } =20 late_initcall(bpf_kprobe_multi_kfuncs_init); + +__bpf_kfunc_start_defs(); + +__bpf_kfunc int bpf_send_signal_remote(struct task_struct *task, int sig, = enum pid_type type, + int value) +{ + struct send_signal_irq_work *work =3D NULL; + kernel_siginfo_t info; + + if (type !=3D PIDTYPE_PID && type !=3D PIDTYPE_TGID) + return -EINVAL; + if (unlikely(task->flags & (PF_KTHREAD | PF_EXITING))) + return -EPERM; + if (unlikely(!nmi_uaccess_okay())) + return -EPERM; + /* Task should not be pid=3D1 to avoid kernel panic. */ + if (unlikely(is_global_init(task))) + return -EPERM; + + clear_siginfo(&info); + info.si_signo =3D sig; + info.si_errno =3D 0; + info.si_code =3D SI_KERNEL; + info.si_pid =3D 0; + info.si_uid =3D 0; + info.si_value.sival_int =3D value; + + if (irqs_disabled()) { + /* Do an early check on signal validity. Otherwise, + * the error is lost in deferred irq_work. + */ + if (unlikely(!valid_signal(sig))) + return -EINVAL; + + work =3D this_cpu_ptr(&send_signal_work); + if (irq_work_is_busy(&work->irq_work)) + return -EBUSY; + + work->task =3D get_task_struct(task); + work->is_siginfo =3D true; + work->info =3D info; + work->sig =3D sig; + work->type =3D type; + work->value =3D value; + irq_work_queue(&work->irq_work); + return 0; + } + + return group_send_sig_info(sig, &info, task, type); +} + +__bpf_kfunc_end_defs(); + +BTF_KFUNCS_START(send_signal_kfunc_ids) +BTF_ID_FLAGS(func, bpf_send_signal_remote, KF_TRUSTED_ARGS) +BTF_KFUNCS_END(send_signal_kfunc_ids) + +static const struct btf_kfunc_id_set bpf_send_signal_kfunc_set =3D { + .owner =3D THIS_MODULE, + .set =3D &send_signal_kfunc_ids, +}; + +static int __init bpf_send_signal_kfuncs_init(void) +{ + return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_send_signal_= kfunc_set); +} + +late_initcall(bpf_send_signal_kfuncs_init); --=20 2.40.1 From nobody Thu Nov 28 22:42:51 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 04F43156230; Thu, 26 Sep 2024 11:53:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727351640; cv=none; b=paZEEFkHOc1XBoMGWWMAe0CKZqxESrZ0C4Dhq2hO3T4I8YoiYF3tr8SgyeBSVBt2ifaCAeEbaFB0cvDQRzCNCXqlOak5ng0bKv8mSNvEByEwKkNQorLcs5jBdAfOIg/inVyNwLFpwAW2dDq2gM0Pq3Z2iB7UeZdw43y2E6eEtmg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727351640; c=relaxed/simple; bh=ldoq/21Iy8XOxX/1iQ6TNqo+98qmfhdsNcodCAQ09Io=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Vb9h9ZNxaQpjlTWsoRYvrZY9StbRFwm7itRvjQdBWoDsmnULiyckbJ3z9ebDqYH5Lf4kj3ZVXHR0bU/6B9TuhTj4lg66DnYqLXcWFFAXaa7VYO/iHOLIJ8kWWpjLOsg35Pmad1oO013Pwd5fGxsCg6t8rC/6L2uEQtHmLzlSS7M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=vMiLZ7pz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="vMiLZ7pz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5C4D1C4CEC5; Thu, 26 Sep 2024 11:53:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727351639; bh=ldoq/21Iy8XOxX/1iQ6TNqo+98qmfhdsNcodCAQ09Io=; h=From:To:Subject:Date:In-Reply-To:References:From; b=vMiLZ7pzmIyRwyZFaRNQd4JqEKy9ZK8kSUbIxiCvazs9iE9KwMUaM2lSMtGSu8R+g hcDWtNYgURtRVZbAo51maeBoSKsBOXRSVpInslqs/XnHSGIwLsvQlkrNbwEyTI7Tni LW37extN0HxHdDJnXZbm1P5KlbDvUF2XcprvK3gAAt9imGsmKoEXaZbL84N5cAoBw8 7yzJxEaSCb0SV/So7dREb2LjuMSsMftuG58Q83KZ8nYx6D6D28vspI5LiIcal1FkrS DxUsSlxBjvp6FP9FKfHS/MC74oB7SLOjdbE3s7VyNFPDaz4HozryDCJkkDizY2xgoa 8v/Z/gjVPe2sQ== From: Puranjay Mohan To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , bpf@vger.kernel.org, linux-kernel@vger.kernel.org, puranjay12@gmail.com Subject: [PATCH bpf-next v2 2/2] selftests/bpf: Augment send_signal test with remote signaling Date: Thu, 26 Sep 2024 11:53:28 +0000 Message-Id: <20240926115328.105634-3-puranjay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240926115328.105634-1-puranjay@kernel.org> References: <20240926115328.105634-1-puranjay@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add testcases to test bpf_send_signal_remote(). In these new test cases, the main process triggers the BPF program and the forked process receives the signals. The target process's signal handler receives a cookie from the bpf program. Signed-off-by: Puranjay Mohan --- .../selftests/bpf/prog_tests/send_signal.c | 133 +++++++++++++----- .../bpf/progs/test_send_signal_kern.c | 35 ++++- 2 files changed, 130 insertions(+), 38 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/t= esting/selftests/bpf/prog_tests/send_signal.c index 6cc69900b3106..beb771347a503 100644 --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c @@ -8,17 +8,25 @@ static int sigusr1_received; =20 static void sigusr1_handler(int signum) { - sigusr1_received =3D 1; + sigusr1_received =3D 8; +} + +static void sigusr1_siginfo_handler(int s, siginfo_t *i, void *v) +{ + sigusr1_received =3D i->si_value.sival_int; } =20 static void test_send_signal_common(struct perf_event_attr *attr, - bool signal_thread) + bool signal_thread, bool remote) { struct test_send_signal_kern *skel; + struct sigaction sa; int pipe_c2p[2], pipe_p2c[2]; int err =3D -1, pmu_fd =3D -1; + volatile int j =3D 0; char buf[256]; pid_t pid; + int old_prio; =20 if (!ASSERT_OK(pipe(pipe_c2p), "pipe_c2p")) return; @@ -39,11 +47,14 @@ static void test_send_signal_common(struct perf_event_a= ttr *attr, } =20 if (pid =3D=3D 0) { - int old_prio; - volatile int j =3D 0; - /* install signal handler and notify parent */ - ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal"); + if (remote) { + sa.sa_sigaction =3D sigusr1_siginfo_handler; + sa.sa_flags =3D SA_RESTART | SA_SIGINFO; + ASSERT_NEQ(sigaction(SIGUSR1, &sa, NULL), -1, "sigaction"); + } else { + ASSERT_NEQ(signal(SIGUSR1, sigusr1_handler), SIG_ERR, "signal"); + } =20 close(pipe_c2p[0]); /* close read */ close(pipe_p2c[1]); /* close write */ @@ -52,10 +63,12 @@ static void test_send_signal_common(struct perf_event_a= ttr *attr, * that if an interrupt happens, the underlying task * is this process. */ - errno =3D 0; - old_prio =3D getpriority(PRIO_PROCESS, 0); - ASSERT_OK(errno, "getpriority"); - ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority"); + if (!remote) { + errno =3D 0; + old_prio =3D getpriority(PRIO_PROCESS, 0); + ASSERT_OK(errno, "getpriority"); + ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority"); + } =20 /* notify parent signal handler is installed */ ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write"); @@ -66,20 +79,25 @@ static void test_send_signal_common(struct perf_event_a= ttr *attr, /* wait a little for signal handler */ for (int i =3D 0; i < 1000000000 && !sigusr1_received; i++) { j /=3D i + j + 1; - if (!attr) - /* trigger the nanosleep tracepoint program. */ - usleep(1); + if (remote) + sleep(1); + else + if (!attr) + /* trigger the nanosleep tracepoint program. */ + usleep(1); } =20 - buf[0] =3D sigusr1_received ? '2' : '0'; - ASSERT_EQ(sigusr1_received, 1, "sigusr1_received"); + buf[0] =3D sigusr1_received; + + ASSERT_EQ(sigusr1_received, 8, "sigusr1_received"); ASSERT_EQ(write(pipe_c2p[1], buf, 1), 1, "pipe_write"); =20 /* wait for parent notification and exit */ ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read"); =20 /* restore the old priority */ - ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority"); + if (!remote) + ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority"); =20 close(pipe_c2p[1]); close(pipe_p2c[0]); @@ -93,6 +111,17 @@ static void test_send_signal_common(struct perf_event_a= ttr *attr, if (!ASSERT_OK_PTR(skel, "skel_open_and_load")) goto skel_open_load_failure; =20 + /* boost with a high priority so we got a higher chance + * that if an interrupt happens, the underlying task + * is this process. + */ + if (remote) { + errno =3D 0; + old_prio =3D getpriority(PRIO_PROCESS, 0); + ASSERT_OK(errno, "getpriority"); + ASSERT_OK(setpriority(PRIO_PROCESS, 0, -20), "setpriority"); + } + if (!attr) { err =3D test_send_signal_kern__attach(skel); if (!ASSERT_OK(err, "skel_attach")) { @@ -100,8 +129,12 @@ static void test_send_signal_common(struct perf_event_= attr *attr, goto destroy_skel; } } else { - pmu_fd =3D syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */, - -1 /* group id */, 0 /* flags */); + if (!remote) + pmu_fd =3D syscall(__NR_perf_event_open, attr, pid, -1 /* cpu */, + -1 /* group id */, 0 /* flags */); + else + pmu_fd =3D syscall(__NR_perf_event_open, attr, getpid(), -1 /* cpu */, + -1 /* group id */, 0 /* flags */); if (!ASSERT_GE(pmu_fd, 0, "perf_event_open")) { err =3D -1; goto destroy_skel; @@ -119,11 +152,30 @@ static void test_send_signal_common(struct perf_event= _attr *attr, /* trigger the bpf send_signal */ skel->bss->signal_thread =3D signal_thread; skel->bss->sig =3D SIGUSR1; - skel->bss->pid =3D pid; + if (!remote) { + skel->bss->target_pid =3D 0; + skel->bss->pid =3D pid; + } else { + skel->bss->target_pid =3D pid; + skel->bss->pid =3D getpid(); + } =20 /* notify child that bpf program can send_signal now */ ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write"); =20 + /* For the remote test, the BPF program is triggered from this + * process but the other process/thread is signaled. + */ + if (remote) { + if (!attr) { + for (int i =3D 0; i < 10; i++) + usleep(1); + } else { + for (int i =3D 0; i < 100000000; i++) + j /=3D i + 1; + } + } + /* wait for result */ err =3D read(pipe_c2p[0], buf, 1); if (!ASSERT_GE(err, 0, "reading pipe")) @@ -133,7 +185,7 @@ static void test_send_signal_common(struct perf_event_a= ttr *attr, goto disable_pmu; } =20 - ASSERT_EQ(buf[0], '2', "incorrect result"); + ASSERT_EQ(buf[0], 8, "incorrect result"); =20 /* notify child safe to exit */ ASSERT_EQ(write(pipe_p2c[1], buf, 1), 1, "pipe_write"); @@ -142,18 +194,21 @@ static void test_send_signal_common(struct perf_event= _attr *attr, close(pmu_fd); destroy_skel: test_send_signal_kern__destroy(skel); + /* restore the old priority */ + if (remote) + ASSERT_OK(setpriority(PRIO_PROCESS, 0, old_prio), "setpriority"); skel_open_load_failure: close(pipe_c2p[0]); close(pipe_p2c[1]); wait(NULL); } =20 -static void test_send_signal_tracepoint(bool signal_thread) +static void test_send_signal_tracepoint(bool signal_thread, bool remote) { - test_send_signal_common(NULL, signal_thread); + test_send_signal_common(NULL, signal_thread, remote); } =20 -static void test_send_signal_perf(bool signal_thread) +static void test_send_signal_perf(bool signal_thread, bool remote) { struct perf_event_attr attr =3D { .freq =3D 1, @@ -162,10 +217,10 @@ static void test_send_signal_perf(bool signal_thread) .config =3D PERF_COUNT_SW_CPU_CLOCK, }; =20 - test_send_signal_common(&attr, signal_thread); + test_send_signal_common(&attr, signal_thread, remote); } =20 -static void test_send_signal_nmi(bool signal_thread) +static void test_send_signal_nmi(bool signal_thread, bool remote) { struct perf_event_attr attr =3D { .sample_period =3D 1, @@ -191,21 +246,35 @@ static void test_send_signal_nmi(bool signal_thread) close(pmu_fd); } =20 - test_send_signal_common(&attr, signal_thread); + test_send_signal_common(&attr, signal_thread, remote); } =20 void test_send_signal(void) { if (test__start_subtest("send_signal_tracepoint")) - test_send_signal_tracepoint(false); + test_send_signal_tracepoint(false, false); if (test__start_subtest("send_signal_perf")) - test_send_signal_perf(false); + test_send_signal_perf(false, false); if (test__start_subtest("send_signal_nmi")) - test_send_signal_nmi(false); + test_send_signal_nmi(false, false); if (test__start_subtest("send_signal_tracepoint_thread")) - test_send_signal_tracepoint(true); + test_send_signal_tracepoint(true, false); if (test__start_subtest("send_signal_perf_thread")) - test_send_signal_perf(true); + test_send_signal_perf(true, false); if (test__start_subtest("send_signal_nmi_thread")) - test_send_signal_nmi(true); + test_send_signal_nmi(true, false); + + /* Signal remote thread and thread group */ + if (test__start_subtest("send_signal_tracepoint_remote")) + test_send_signal_tracepoint(false, true); + if (test__start_subtest("send_signal_perf_remote")) + test_send_signal_perf(false, true); + if (test__start_subtest("send_signal_nmi_remote")) + test_send_signal_nmi(false, true); + if (test__start_subtest("send_signal_tracepoint_thread_remote")) + test_send_signal_tracepoint(true, true); + if (test__start_subtest("send_signal_perf_thread_remote")) + test_send_signal_perf(true, true); + if (test__start_subtest("send_signal_nmi_thread_remote")) + test_send_signal_nmi(true, true); } diff --git a/tools/testing/selftests/bpf/progs/test_send_signal_kern.c b/to= ols/testing/selftests/bpf/progs/test_send_signal_kern.c index 92354cd720440..4f25b60fe05b2 100644 --- a/tools/testing/selftests/bpf/progs/test_send_signal_kern.c +++ b/tools/testing/selftests/bpf/progs/test_send_signal_kern.c @@ -1,27 +1,50 @@ // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook -#include +#include #include #include =20 -__u32 sig =3D 0, pid =3D 0, status =3D 0, signal_thread =3D 0; +struct task_struct *bpf_task_from_pid(int pid) __ksym; +void bpf_task_release(struct task_struct *p) __ksym; +int bpf_send_signal_remote(struct task_struct *task, int sig, enum pid_typ= e type, int value) __ksym; + +__u32 sig =3D 0, pid =3D 0, status =3D 0, signal_thread =3D 0, target_pid = =3D 0; =20 static __always_inline int bpf_send_signal_test(void *ctx) { + struct task_struct *target_task =3D NULL; int ret; + int value; =20 if (status !=3D 0 || pid =3D=3D 0) return 0; =20 if ((bpf_get_current_pid_tgid() >> 32) =3D=3D pid) { - if (signal_thread) - ret =3D bpf_send_signal_thread(sig); - else - ret =3D bpf_send_signal(sig); + if (target_pid) { + target_task =3D bpf_task_from_pid(target_pid); + if (!target_task) + return 0; + value =3D 8; + } + + if (signal_thread) { + if (target_pid) + ret =3D bpf_send_signal_remote(target_task, sig, PIDTYPE_PID, value); + else + ret =3D bpf_send_signal_thread(sig); + } else { + if (target_pid) + ret =3D bpf_send_signal_remote(target_task, sig, PIDTYPE_TGID, value); + else + ret =3D bpf_send_signal(sig); + } if (ret =3D=3D 0) status =3D 1; } =20 + if (target_task) + bpf_task_release(target_task); + return 0; } =20 --=20 2.40.1