From mboxrd@z Thu Jan 1 00:00:00 1970 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 27228171BB; Fri, 8 May 2026 00:33:55 +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=1778200435; cv=none; b=pgzly6H9+9oLI16vWgNaGdPP/ZBo9l0Z5HbJIuDPx8DIYKT7pyGB/ZEJCkhaE/RxqH1KimsDSv9+i9YGXe4P4qJswvO5X6k48pkVTSkaBbh5F00QhNxe69kFJPkSZoWVnWoDJccZLi9sj99pj7KP6rpnguG0TBdMeJEZ9ldqayI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778200435; c=relaxed/simple; bh=4yVKlDBPodn92aHkB9CfoMEo3fAc5fA1bRmJ249Zmqw=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=VyxfmpXnFpbrjAup1J7LC1qzmatmSySVtMlM+mKJndbDW7OzhlXKLuhbMeqMNdmqw5WOo8wrptbmFCOU3Vpeg+bWFmT8Z5zNfsoiWnjfTSFELiENcD2Jtxanc2bwSDbU+thHuDbUA042oLnG5OlMJpYI+tS0ox+nIZ74uFrfS3A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DkVsZi5w; 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="DkVsZi5w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6841EC2BCB2; Fri, 8 May 2026 00:33:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778200435; bh=4yVKlDBPodn92aHkB9CfoMEo3fAc5fA1bRmJ249Zmqw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=DkVsZi5wdHEGGdtf8S6NVAtfEick4K5rJmbVPaa/BgRPTKJ1KcOQa8bJGWsemw8mL JiHMMxW3CV2fBRvBoH5BpjVrr0vcZTqnYgHAibB0AfnE0x4JnxLv4dXWquvxOXKARb W1uEWEq/76/uiuxW5Avsq0ej+Gekj88HJgzzOvSUZaHLIJj1HyEfYJjzQ/bXm1qVjJ DQEolXzJcdfCIDagzAJH+nnXpU1HbTeVHneFSjcI88heJbSUMUXzUqV1BPLe65Vx45 pvDwCzIoibmIt9Xc+8RmS4kqf3zYn037XjgmShrKnsYRJvJr7WdtDSTisgkE9DaNyN wPUUR+dIOvRFA== Date: Fri, 8 May 2026 09:33:50 +0900 From: Masami Hiramatsu (Google) To: Martin Kaiser Cc: Naveen N Rao , Steven Rostedt , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] test_kprobes: clear kprobes between test runs Message-Id: <20260508093350.1d03d6c239134a5bc02c61de@kernel.org> In-Reply-To: <20260507134615.1010905-1-martin@kaiser.cx> References: <20260507134615.1010905-1-martin@kaiser.cx> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 7 May 2026 15:44:33 +0200 Martin Kaiser wrote: > Running the kprobes sanity tests twice makes all tests fail and > eventually crashes the kernel. > > [root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run > ... > # Totals: pass:5 fail:0 skip:0 total:5 > ok 1 kprobes_test > [root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run > ... > # test_kprobe: EXPECTATION FAILED at lib/tests/test_kprobes.c:64 > Expected 0 == register_kprobe(&kp), but > register_kprobe(&kp) == -22 (0xffffffffffffffea) > ... > Unable to handle kernel paging request ... Oops, good catch! Thanks for fixing! > > The testsuite defines several kprobes and kretprobes as static variables > that are preserved across test runs. > > After register_kprobe and unregister_kprobe, a kprobe contains some > leftover data that must be cleared before the kprobe can be registered > again. The tests are setting symbol_name to define the probe location. > Address and flags must be cleared. > > The existing code clears some of the probes between subsequent tests, but > not between two test runs. The leftover data from a previous test run > makes the registrations fail in the next run. > > Move the cleanups for all kprobes into kprobes_test_init, this function > is called before each single test (including the first test of a test > run). Yeah, this looks good to me. Let me pick it. > > Signed-off-by: Martin Kaiser > --- > lib/tests/test_kprobes.c | 29 ++++++++++++++++++----------- > 1 file changed, 18 insertions(+), 11 deletions(-) > > diff --git a/lib/tests/test_kprobes.c b/lib/tests/test_kprobes.c > index b7582010125c..06e729e4de05 100644 > --- a/lib/tests/test_kprobes.c > +++ b/lib/tests/test_kprobes.c > @@ -12,6 +12,12 @@ > > #define div_factor 3 > > +#define KP_CLEAR(_kp) \ > +do { \ > + (_kp).addr = NULL; \ > + (_kp).flags = 0; \ > +} while (0) > + > static u32 rand1, preh_val, posth_val; > static u32 (*target)(u32 value); > static u32 (*recursed_target)(u32 value); > @@ -125,10 +131,6 @@ static void test_kprobes(struct kunit *test) > > current_test = test; > > - /* addr and flags should be cleard for reusing kprobe. */ > - kp.addr = NULL; > - kp.flags = 0; > - > KUNIT_EXPECT_EQ(test, 0, register_kprobes(kps, 2)); > preh_val = 0; > posth_val = 0; > @@ -226,9 +228,6 @@ static void test_kretprobes(struct kunit *test) > struct kretprobe *rps[2] = {&rp, &rp2}; > > current_test = test; > - /* addr and flags should be cleard for reusing kprobe. */ > - rp.kp.addr = NULL; > - rp.kp.flags = 0; > KUNIT_EXPECT_EQ(test, 0, register_kretprobes(rps, 2)); > > krph_val = 0; > @@ -290,8 +289,6 @@ static void test_stacktrace_on_kretprobe(struct kunit *test) > unsigned long myretaddr = (unsigned long)__builtin_return_address(0); > > current_test = test; > - rp3.kp.addr = NULL; > - rp3.kp.flags = 0; > > /* > * Run the stacktrace_driver() to record correct return address in > @@ -352,8 +349,6 @@ static void test_stacktrace_on_nested_kretprobe(struct kunit *test) > struct kretprobe *rps[2] = {&rp3, &rp4}; > > current_test = test; > - rp3.kp.addr = NULL; > - rp3.kp.flags = 0; > > //KUNIT_ASSERT_NE(test, myretaddr, stacktrace_driver()); > > @@ -367,6 +362,18 @@ static void test_stacktrace_on_nested_kretprobe(struct kunit *test) > > static int kprobes_test_init(struct kunit *test) > { > + KP_CLEAR(kp); > + KP_CLEAR(kp2); > + KP_CLEAR(kp_missed); > +#ifdef CONFIG_KRETPROBES > + KP_CLEAR(rp.kp); > + KP_CLEAR(rp2.kp); > +#ifdef CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE > + KP_CLEAR(rp3.kp); > + KP_CLEAR(rp4.kp); > +#endif > +#endif > + > target = kprobe_target; > target2 = kprobe_target2; > recursed_target = kprobe_recursed_target; > -- > 2.43.7 > -- Masami Hiramatsu (Google)