From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-189.mta1.migadu.com (out-189.mta1.migadu.com [95.215.58.189]) (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 03DF81A294 for ; Thu, 2 Apr 2026 04:14:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.189 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775103244; cv=none; b=V9VcyGU5j82oDsF0grpacJCSfTUwdk/GI71MA1eHTmQ0GudxGgi1eRhemrWATLI3mEnY2K8UkN2SXgDhKLDXkJmhaVMvYZiYoQwsASYqnT7IG1gW8e1eAzyRVQKOoI66NzJ7LdXihokZPEuWeg7G6nfcllsTMSeMl40vrtiQE9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775103244; c=relaxed/simple; bh=FUX31B9jO+2YDQ//I9SUc7yjDD/x+fdGS1AQ6NG66K8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HL8mutZxOaQpSPlD7jqid0xu6Zgb6W0li9ZPKfUdr2+0d4YWTvLxpXP2b5OPC8v+yRKUqe6GGkekCyECD8CVIHfZu5OetoRSXGVNmZm5V0YAh6nAI4+gWFjSCxjKoVxvQpXKunyWbbQGYMlsKyB8iGVwlhYgPDZxE8pidpTq0uY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ptyE7T95; arc=none smtp.client-ip=95.215.58.189 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ptyE7T95" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1775103241; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4cP9KTGZrxxjUnGTO4F59TXW5UOjeg7N0Y/qlqLazzA=; b=ptyE7T95rQqp90FJFQcwnePl4shSKs+OyJo8gP56+M3v46+K+UMxCzzTTBrPA2h59j6YdP 7snmzILy5vxC/gSFhqaoYFwy9If89jwvX20gPx3IUKUir4S5Zt/hz2YRAGEhWHBWH6WnCO 8r9uNmmF5gfEq6euDolfeHw9x8wnnao= Date: Thu, 2 Apr 2026 12:13:49 +0800 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf v3 2/2] selftests/bpf: Add test to ensure kprobe_multi is not sleepable Content-Language: en-US To: Varun R Mallya , bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, memxor@gmail.com, yonghong.song@linux.dev, jolsa@kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org References: <20260401191126.440683-1-varunrmallya@gmail.com> <20260401191126.440683-2-varunrmallya@gmail.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Leon Hwang In-Reply-To: <20260401191126.440683-2-varunrmallya@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT Above all, I think the test should reproduce the BUG without the fix. I update the test to reproduce the BUG, then verify that the BUG will be rejected with the fix. The updated test is attached at last. On 2/4/26 03:11, Varun R Mallya wrote: > Add a selftest to ensure that kprobe_multi programs cannot be attached > using the BPF_F_SLEEPABLE flag. This test succeeds when the kernel > rejects attachment of kprobe_multi when the BPF_F_SLEEPABLE flag is set. > > Signed-off-by: Varun R Mallya > --- > .../bpf/prog_tests/kprobe_multi_test.c | 41 +++++++++++++++++++ > .../bpf/progs/kprobe_multi_sleepable.c | 13 ++++++ > 2 files changed, 54 insertions(+) > create mode 100644 tools/testing/selftests/bpf/progs/kprobe_multi_sleepable.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c > index 78c974d4ea33..f02fec2b6fda 100644 > --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c > +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c > @@ -10,6 +10,7 @@ > #include "kprobe_multi_session_cookie.skel.h" > #include "kprobe_multi_verifier.skel.h" > #include "kprobe_write_ctx.skel.h" > +#include "kprobe_multi_sleepable.skel.h" > #include "bpf/libbpf_internal.h" > #include "bpf/hashmap.h" > > @@ -633,6 +634,44 @@ static void test_attach_write_ctx(void) > } > #endif > > +static void test_attach_multi_sleepable(void) > +{ > + struct kprobe_multi_sleepable *skel; > + int err; > + > + skel = kprobe_multi_sleepable__open(); > + if (!ASSERT_OK_PTR(skel, "kprobe_multi_sleepable__open")) > + return; > + > + err = bpf_program__set_flags(skel->progs.handle_kprobe_multi_sleepable, > + BPF_F_SLEEPABLE); > + if (!ASSERT_OK(err, "bpf_program__set_flags")) > + goto cleanup; > + > + /* Load should succeed even with BPF_F_SLEEPABLE for KPROBE types */ > + err = kprobe_multi_sleepable__load(skel); > + if (!ASSERT_OK(err, "kprobe_multi_sleepable__load")) > + goto cleanup; > + > + /* Attachment must fail for kprobe.multi + BPF_F_SLEEPABLE. > + * Also chosen a stable symbol to send into opts > + */ > + LIBBPF_OPTS(bpf_kprobe_multi_opts, opts); > + const char *sym = "vfs_read"; They should stay with skel and err. See below. > + > + opts.syms = &sym; > + opts.cnt = 1; > + > + skel->links.handle_kprobe_multi_sleepable = > + bpf_program__attach_kprobe_multi_opts(skel->progs.handle_kprobe_multi_sleepable, > + NULL, &opts); > + ASSERT_ERR_PTR(skel->links.handle_kprobe_multi_sleepable, > + "bpf_program__attach_kprobe_multi_opts"); As Kumar suggested, better to also verify the error here. ASSERT_EQ(libbpf_get_error(skel->links.handle_kprobe_multi_sleepable), -EINVAL, "bpf_program__attach_kprobe_multi_opts error"); > + > +cleanup: > + kprobe_multi_sleepable__destroy(skel); > +} > + [...] Thanks, Leon --- diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c index 78c974d4ea33..d59cf840da83 100644 --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c @@ -10,6 +10,7 @@ #include "kprobe_multi_session_cookie.skel.h" #include "kprobe_multi_verifier.skel.h" #include "kprobe_write_ctx.skel.h" +#include "kprobe_multi_sleepable.skel.h" #include "bpf/libbpf_internal.h" #include "bpf/hashmap.h" @@ -633,6 +634,52 @@ static void test_attach_write_ctx(void) } #endif +static void test_attach_multi_sleepable(void) +{ + struct kprobe_multi_sleepable *skel; + const char *sym = "bpf_fentry_test1"; + int err; + LIBBPF_OPTS(bpf_test_run_opts, topts); + LIBBPF_OPTS(bpf_kprobe_multi_opts, opts, + .syms = &sym, + .cnt = 1 + ); + + skel = kprobe_multi_sleepable__open(); + if (!ASSERT_OK_PTR(skel, "kprobe_multi_sleepable__open")) + return; + + skel->bss->user_ptr = skel; + + err = bpf_program__set_flags(skel->progs.handle_kprobe_multi_sleepable, + BPF_F_SLEEPABLE); + if (!ASSERT_OK(err, "bpf_program__set_flags")) + goto cleanup; + + /* Load should succeed even with BPF_F_SLEEPABLE for KPROBE types */ + err = kprobe_multi_sleepable__load(skel); + if (!ASSERT_OK(err, "kprobe_multi_sleepable__load")) + goto cleanup; + + /* + * Attachment must fail for kprobe.multi + BPF_F_SLEEPABLE. + * Also chosen a stable symbol to send into opts + */ + skel->links.handle_kprobe_multi_sleepable = + bpf_program__attach_kprobe_multi_opts(skel->progs.handle_kprobe_multi_sleepable, + NULL, &opts); + ASSERT_ERR_PTR(skel->links.handle_kprobe_multi_sleepable, + "bpf_program__attach_kprobe_multi_opts"); + ASSERT_EQ(libbpf_get_error(skel->links.handle_kprobe_multi_sleepable), -EINVAL, + "attach_multi_sleepable_err"); + + err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.fentry), &topts); + ASSERT_OK(err, "bpf_prog_test_run_opts"); + +cleanup: + kprobe_multi_sleepable__destroy(skel); +} + void serial_test_kprobe_multi_bench_attach(void) { if (test__start_subtest("kernel")) @@ -676,5 +723,7 @@ void test_kprobe_multi_test(void) test_unique_match(); if (test__start_subtest("attach_write_ctx")) test_attach_write_ctx(); + if (test__start_subtest("attach_multi_sleepable")) + test_attach_multi_sleepable(); RUN_TESTS(kprobe_multi_verifier); } diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi_sleepable.c b/tools/testing/selftests/bpf/progs/kprobe_multi_sleepable.c new file mode 100644 index 000000000000..932e1d9c72e2 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/kprobe_multi_sleepable.c @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "vmlinux.h" +#include +#include + +void *user_ptr = 0; + +SEC("kprobe.multi") +int handle_kprobe_multi_sleepable(struct pt_regs *ctx) +{ + int a, err; + + err = bpf_copy_from_user(&a, sizeof(a), user_ptr); + barrier_var(a); + return err; +} + +SEC("fentry/bpf_fentry_test1") +int BPF_PROG(fentry) +{ + return 0; +} + +char _license[] SEC("license") = "GPL";