From nobody Sun Feb 8 14:31:13 2026 Received: from out203-205-221-149.mail.qq.com (out203-205-221-149.mail.qq.com [203.205.221.149]) (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 03E771D9346; Wed, 28 Jan 2026 07:16:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.205.221.149 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769584590; cv=none; b=WM8dE4M9+LHlra+4FWk4GN2SH07V0EbT2v46JzvmsEdKq3gi27EdYdtBRnmhVJIzEiHxiY9mwFDSLAwje6nk/s4+S7E2grK/c0Cv1BpfIhX0AG7BC6o8+ar9rA3X2t0irXnOLqCxC3py4KzfQbohNm/VEwT1PPvpcCJV+tdbcyE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769584590; c=relaxed/simple; bh=cc/4MvYQW3AVaMospqyppf/6T8Bhygb2pcx1Oiu99M8=; h=Message-ID:From:To:Cc:Subject:Date:MIME-Version:Content-Type; b=H8b9ui+Y0xiu9HxjyhQcisoponhNWgvSs5S75uCJQ0dlPjpzuUB7LcAViWwyiUBmucdko+eocavQ4EIH7L/1sGkUSW+iUp1b6zi6MoAUStYPdc+bQoid2yH9+tkrmoifkCWSZ4cL71MdTqZQzrtUvBzXY5ZcEFPlF7NKTXhRJaE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=foxmail.com; spf=pass smtp.mailfrom=foxmail.com; dkim=pass (1024-bit key) header.d=foxmail.com header.i=@foxmail.com header.b=X9ce2+1Z; arc=none smtp.client-ip=203.205.221.149 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=foxmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=foxmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=foxmail.com header.i=@foxmail.com header.b="X9ce2+1Z" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foxmail.com; s=s201512; t=1769584578; bh=UsOMW+fH/0u09b+I9Maxdl9lX3AzM+KsG85N0ClPTyc=; h=From:To:Cc:Subject:Date; b=X9ce2+1ZXsjCEsptq/NrjPwiuDlWAggTlIcijLXL1VMBkgQZnaPiW80aHIptL8h4u /twSVgqW+3WukWxSDxyLlUZJhECLoJi/lK/wzD6raWSJuTHMyrQvysOXTF2nH0sJy8 TpoACiT/xvttEJMpygYy4QFFRTZpNlvXc90DCsx0= Received: from meizu-Precision-3660.meizu.com ([14.21.33.152]) by newxmesmtplogicsvrszc50-0.qq.com (NewEsmtp) with SMTP id 40E82410; Wed, 28 Jan 2026 15:16:14 +0800 X-QQ-mid: xmsmtpt1769584574tpqv0ipnd Message-ID: X-QQ-XMAILINFO: M9B58rdLYxrLjCqmWwUQoEih+LW97yLf1OdkCA7vnUGLQ+kDRxqiTcgglZJkyD qd0XtXOZaHeRu4Cdwh2BnsBbcKO2j428bCpEPmvc76KUJHHZLvqMRpw+dBxh+JP1YnDC+XTPp+9R pDwm8N/JHvuRZ9CKVapHVHuvlV9+FOr4MYYBvKU5GwVc0B9iXYWyHhbnjTH1XJEoUNRYBL2+evD1 0ThthzD8I4aX3pP2C/hR1SrMbyhOmeCav9IClwOz68HUZ8SkAK/7c1eLHp7XJoyjHP1djKjbMJF/ wCQ037zaEo904ptmOdiv7INvKKLY95NXNsvHxSJ8P77QP08Kd8fFwAesanCSjCdVX7c6hSOC9AT/ bFsi796DGDQ7AuA8Tk5lJoEdT81GFawxSjNzTewgNybfvw+TW5SoerPPMzvQ6faKw8a26pCypPAj u00UstW9FmMzVq8WvVmr07qrOr8B7KbDEa1nTvBNFqwrEPEJt7892E0Pe7UnBURUNBs5wt4CxDvj m1axv1epDQ9SOHB+9Y0edpmfdVYPXHXhWzvz/ddgZFfOFDSzocLzIdBQYadkrEvGyV1a97lOQqP5 LNEZI3wHbmsdFiBnnahCiUwmw4r6ZZAZpBvNfzd7Rmg96vdm9Acn9alspCu3dFDPmxBm50He7YV8 1A99WnMhB1QRaizBumt94qAvCPKlT6Q8OjhFj4tqLQAJF/OyOS5DOoD2k4UXY9eewRRgcgAVi4SH ZQ8RCrKc1/TswqQ18jJTySPXuDzpdy7D75PV30aEcEvWNn8mFZ+l4H4ey6nRJD+NQG5PjCZE01C/ dViUPdbuwq3wzNZoUGtu4zneuSkuxglmpa/Gaow3ed7LEAzcqXeTeyNjlP/YRnRAy573cJyoxDDn CHM96GFYDtDr7kuOQWkcrlr1lyAMpzEHCJPJ0ptPVrDeBDrq4zXP91NuzDHbFF5r2cHPpCAHSCMK YZvkC4yjGc9PW1RNgMOOWzHDEiRVNx13/r/E/CgHbYH2N43mI4nmrvWF/oGo/BOTibValE5ualMD hxpyj2JaXvFFU3EOTEACTq+rpoBju0oLuyd7PHf+YKvtmjWHKs339ZHZM8ROooQWleJLq0UjIXJg lyb46DJl4d44FPQFOGR4hk4LWvmnEt4ZC0X7Da X-QQ-XMRINFO: NS+P29fieYNwqS3WCnRCOn9D1NpZuCnCRA== From: Yuwen Chen To: tglx@kernel.org Cc: akpm@linux-foundation.org, andrealmeid@igalia.com, bigeasy@linutronix.de, colin.i.king@gmail.com, dave@stgolabs.net, dvhart@infradead.org, edliaw@google.com, justinstitt@google.com, kernel-team@android.com, licayy@foxmail.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, luto@mit.edu, mingo@redhat.com, morbo@google.com, nathan@kernel.org, ndesaulniers@google.com, peterz@infradead.org, shuah@kernel.org, usama.anjum@collabora.com, wakel@google.com, Yuwen Chen Subject: [PATCH v3] selftests/futex: fix the failed futex_requeue test issue Date: Wed, 28 Jan 2026 15:16:12 +0800 X-OQ-MSGID: <20260128071612.416371-1-ywen.chen@foxmail.com> X-Mailer: git-send-email 2.34.1 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="utf-8" Content-Transfer-Encoding: quoted-printable This test item has extremely high requirements for timing and can only pass the test under specific conditions. The following situations will lead to test failure: MainThread Thread1 =E2=94=82 pthread_create-------------------=E2=94=90 =E2=94=82 =E2=94=82 futex_cmp_requeue =E2=94=82 =E2=94=82 futex_wait =E2=94=82 =E2=94=82 If the child thread is not waiting in the futex_wait function when the main thread reaches the futex_cmp_requeue function, the test will fail. This patch avoids this problem by checking whether the child thread is in a sleeping state in the main thread. Fixes: 7cb5dd8e2c8c ("selftests: futex: Add futex compare requeue test") Signed-off-by: Yuwen Chen Co-developed-by: Edward Liaw Signed-off-by: Edward Liaw --- v1->v2: 1. Fix the issue of abnormal use of fscanf in the get_thread_state func= tion 2. Add timeout logic v2->v3: https://lore.kernel.org/all/tencent_B9DBF2ECBE56BAB68BDAB949C6935D0= 1CE09@qq.com/ 1. Use /proc/[pid]/wchan instead of /proc/[pid]/stat to check if a proc= ess has entered the sleep state 2. Refactor part of the logic to facilitate code reuse. .../futex/functional/futex_requeue.c | 91 ++++++++++++++++--- 1 file changed, 77 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/futex/functional/futex_requeue.c b/too= ls/testing/selftests/futex/functional/futex_requeue.c index dcf0d5f2f3122..7163e827691e4 100644 --- a/tools/testing/selftests/futex/functional/futex_requeue.c +++ b/tools/testing/selftests/futex/functional/futex_requeue.c @@ -11,8 +11,9 @@ #include "futextest.h" #include "kselftest_harness.h" =20 -#define timeout_ns 30000000 -#define WAKE_WAIT_US 10000 +#define FUTEX_WAIT_TIMEOUT_S 3 /* 3s */ +#define WAIT_THREAD_RETRIES 100 +#define WAIT_THREAD_DELAY_US (10000 * 100) /* 1s */ =20 volatile futex_t *f1; =20 @@ -20,8 +21,8 @@ void *waiterfn(void *arg) { struct timespec to; =20 - to.tv_sec =3D 0; - to.tv_nsec =3D timeout_ns; + to.tv_sec =3D FUTEX_WAIT_TIMEOUT_S; + to.tv_nsec =3D 0; =20 if (futex_wait(f1, *f1, &to, 0)) printf("waiter failed errno %d\n", errno); @@ -29,20 +30,83 @@ void *waiterfn(void *arg) return NULL; } =20 +struct futex_thread { + pthread_t thread; + pthread_barrier_t barrier; + pid_t tid; + void *(*threadfn)(void *); + void *arg; +}; + +static int wait_for_thread(FILE *fp, int timeout_us) +{ + char buf[80] =3D ""; + + for (int i =3D 0; i < WAIT_THREAD_RETRIES; i++) { + if (!fgets(buf, sizeof(buf), fp)) + return -EIO; + if (!strncmp(buf, "futex", 5)) + return 0; + usleep(timeout_us / WAIT_THREAD_RETRIES); + rewind(fp); + } + return -ETIMEDOUT; +} + +int futex_wait_for_thread(struct futex_thread *t, int timeout_us) +{ + char fname[80]; + FILE *fp; + int res; + + snprintf(fname, sizeof(fname), "/proc/%d/wchan", t->tid); + fp =3D fopen(fname, "r"); + if (!fp) + return -EIO; + res =3D wait_for_thread(fp, timeout_us); + fclose(fp); + return res; +} + +static void *futex_thread_fn(void *arg) +{ + struct futex_thread *t =3D arg; + + t->tid =3D gettid(); + pthread_barrier_wait(&t->barrier); + return t->threadfn(t->arg); +} + +int futex_thread_create(struct futex_thread *t, void *(*threadfn)(void *),= void *arg) +{ + int ret; + + pthread_barrier_init(&t->barrier, NULL, 2); + t->tid =3D 0; + t->threadfn =3D threadfn; + t->arg =3D arg; + + ret =3D pthread_create(&t->thread, NULL, futex_thread_fn, t); + if (ret) + return ret; + + pthread_barrier_wait(&t->barrier); + return 0; +} + TEST(requeue_single) { volatile futex_t _f1 =3D 0; volatile futex_t f2 =3D 0; - pthread_t waiter[10]; + struct futex_thread waiter; =20 f1 =3D &_f1; =20 /* * Requeue a waiter from f1 to f2, and wake f2. */ - ASSERT_EQ(0, pthread_create(&waiter[0], NULL, waiterfn, NULL)); - - usleep(WAKE_WAIT_US); + EXPECT_EQ(0, futex_thread_create(&waiter, waiterfn, NULL)); + futex_wait_for_thread(&waiter, WAIT_THREAD_DELAY_US); =20 EXPECT_EQ(1, futex_cmp_requeue(f1, 0, &f2, 0, 1, 0)); EXPECT_EQ(1, futex_wake(&f2, 1, 0)); @@ -52,8 +116,7 @@ TEST(requeue_multiple) { volatile futex_t _f1 =3D 0; volatile futex_t f2 =3D 0; - pthread_t waiter[10]; - int i; + struct futex_thread waiter[10]; =20 f1 =3D &_f1; =20 @@ -61,10 +124,10 @@ TEST(requeue_multiple) * Create 10 waiters at f1. At futex_requeue, wake 3 and requeue 7. * At futex_wake, wake INT_MAX (should be exactly 7). */ - for (i =3D 0; i < 10; i++) - ASSERT_EQ(0, pthread_create(&waiter[i], NULL, waiterfn, NULL)); - - usleep(WAKE_WAIT_US); + for (int i =3D 0; i < 10; i++) { + EXPECT_EQ(0, futex_thread_create(&waiter[i], waiterfn, NULL)); + futex_wait_for_thread(&waiter[i], WAIT_THREAD_DELAY_US / 10); + } =20 EXPECT_EQ(10, futex_cmp_requeue(f1, 0, &f2, 3, 7, 0)); EXPECT_EQ(7, futex_wake(&f2, INT_MAX, 0)); --=20 2.34.1