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 F0F4F2459DC; Tue, 17 Mar 2026 17:19:52 +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=1773767993; cv=none; b=sart/qWJZgUh7Fe1by+JVBykWePAGWrimMMBH1ijONVqu6xpzK1Fd6GNpwDOBG/bbdW7Domz+dOp6h3AmI02EBYcO4EUKfJE93weT0yJPWSbT77uZn/scPDlW+KWLlhoilXqrYekzote4a8zOa4d59tmIVkgXad/ZptEYKGmmvI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773767993; c=relaxed/simple; bh=fJ6QJa6XO9USKGJd3UVojEtZdlDmtGh0vySKvadjskY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fCpQN9zqmucq8gIkzSrBnG2Vva/AjzIB+TuUwVvGJLK/FCyCbKJn5h4+QMFPEDiw4GdBup0SK/0zrEidafCno51SOtQNdjJ0cZHZMJ8yV5XmVKmYaDrjpUJgyOKbWZNkdMfO7UY9Yy9K0bhEEd35O+2d5e0KX5IXJeRfXp/n9nM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2ZE7BzAN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2ZE7BzAN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FE88C4CEF7; Tue, 17 Mar 2026 17:19:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773767992; bh=fJ6QJa6XO9USKGJd3UVojEtZdlDmtGh0vySKvadjskY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2ZE7BzAN0kwXnRJOn/B5J4B8JaKPh0r+SL8o6NQX6pfsvEgD32eBHsGde+dzNc5fp e/6AgwizdnWpLpiAeKkfqccW48HWwDpZzg2Wt/oh2BDhwXkZLU4hUrQDImQpP/yvCY KyPMToQjKY4nj4BgstPB/nx4dFlne9LC5smXwdbw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Gow , Eric Biggers Subject: [PATCH 6.18 206/333] kunit: irq: Ensure timer doesnt fire too frequently Date: Tue, 17 Mar 2026 17:33:55 +0100 Message-ID: <20260317163006.999274003@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260317162959.345812316@linuxfoundation.org> References: <20260317162959.345812316@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit 201ceb94aa1def0024a7c18ce643e5f65026be06 upstream. Fix a bug where kunit_run_irq_test() could hang if the system is too slow. This was noticed with the crypto library tests in certain VMs. Specifically, if kunit_irq_test_timer_func() and the associated hrtimer code took over 5us to run, then the CPU would spend all its time executing that code in hardirq context. As a result, the task executing kunit_run_irq_test() never had a chance to run, exit the loop, and cancel the timer. To fix it, make kunit_irq_test_timer_func() increase the timer interval when the other contexts aren't having a chance to run. Fixes: 950a81224e8b ("lib/crypto: tests: Add hash-test-template.h and gen-hash-testvecs.py") Cc: stable@vger.kernel.org Reviewed-by: David Gow Link: https://lore.kernel.org/r/20260224033751.97615-1-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Greg Kroah-Hartman --- include/kunit/run-in-irq-context.h | 44 +++++++++++++++++++----------- 1 file changed, 28 insertions(+), 16 deletions(-) diff --git a/include/kunit/run-in-irq-context.h b/include/kunit/run-in-irq-context.h index c89b1b1b12dd..bfe60d6cf28d 100644 --- a/include/kunit/run-in-irq-context.h +++ b/include/kunit/run-in-irq-context.h @@ -12,16 +12,16 @@ #include #include -#define KUNIT_IRQ_TEST_HRTIMER_INTERVAL us_to_ktime(5) - struct kunit_irq_test_state { bool (*func)(void *test_specific_state); void *test_specific_state; bool task_func_reported_failure; bool hardirq_func_reported_failure; bool softirq_func_reported_failure; + atomic_t task_func_calls; atomic_t hardirq_func_calls; atomic_t softirq_func_calls; + ktime_t interval; struct hrtimer timer; struct work_struct bh_work; }; @@ -30,14 +30,25 @@ static enum hrtimer_restart kunit_irq_test_timer_func(struct hrtimer *timer) { struct kunit_irq_test_state *state = container_of(timer, typeof(*state), timer); + int task_calls, hardirq_calls, softirq_calls; WARN_ON_ONCE(!in_hardirq()); - atomic_inc(&state->hardirq_func_calls); + task_calls = atomic_read(&state->task_func_calls); + hardirq_calls = atomic_inc_return(&state->hardirq_func_calls); + softirq_calls = atomic_read(&state->softirq_func_calls); + + /* + * If the timer is firing too often for the softirq or task to ever have + * a chance to run, increase the timer interval. This is needed on very + * slow systems. + */ + if (hardirq_calls >= 20 && (softirq_calls == 0 || task_calls == 0)) + state->interval = ktime_add_ns(state->interval, 250); if (!state->func(state->test_specific_state)) state->hardirq_func_reported_failure = true; - hrtimer_forward_now(&state->timer, KUNIT_IRQ_TEST_HRTIMER_INTERVAL); + hrtimer_forward_now(&state->timer, state->interval); queue_work(system_bh_wq, &state->bh_work); return HRTIMER_RESTART; } @@ -86,10 +97,14 @@ static inline void kunit_run_irq_test(struct kunit *test, bool (*func)(void *), struct kunit_irq_test_state state = { .func = func, .test_specific_state = test_specific_state, + /* + * Start with a 5us timer interval. If the system can't keep + * up, kunit_irq_test_timer_func() will increase it. + */ + .interval = us_to_ktime(5), }; unsigned long end_jiffies; - int hardirq_calls, softirq_calls; - bool allctx = false; + int task_calls, hardirq_calls, softirq_calls; /* * Set up a hrtimer (the way we access hardirq context) and a work @@ -104,21 +119,18 @@ static inline void kunit_run_irq_test(struct kunit *test, bool (*func)(void *), * and hardirq), or 1 second, whichever comes first. */ end_jiffies = jiffies + HZ; - hrtimer_start(&state.timer, KUNIT_IRQ_TEST_HRTIMER_INTERVAL, - HRTIMER_MODE_REL_HARD); - for (int task_calls = 0, calls = 0; - ((calls < max_iterations) || !allctx) && - !time_after(jiffies, end_jiffies); - task_calls++) { + hrtimer_start(&state.timer, state.interval, HRTIMER_MODE_REL_HARD); + do { if (!func(test_specific_state)) state.task_func_reported_failure = true; + task_calls = atomic_inc_return(&state.task_func_calls); hardirq_calls = atomic_read(&state.hardirq_func_calls); softirq_calls = atomic_read(&state.softirq_func_calls); - calls = task_calls + hardirq_calls + softirq_calls; - allctx = (task_calls > 0) && (hardirq_calls > 0) && - (softirq_calls > 0); - } + } while ((task_calls + hardirq_calls + softirq_calls < max_iterations || + (task_calls == 0 || hardirq_calls == 0 || + softirq_calls == 0)) && + !time_after(jiffies, end_jiffies)); /* Cancel the timer and work. */ hrtimer_cancel(&state.timer); -- 2.53.0