From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f47.google.com (mail-ot1-f47.google.com [209.85.210.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E69E753F6BB for ; Tue, 13 Oct 2026 19:19:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791919196; cv=none; b=sIATeFuhVJlBSFR0CdU3kE0n+/cxtL8aruMPaJ6o72insnXjykia/RKlTt9Pvixfl58Dl4xSn2edV6icMqM5BCNJGG9V6UokPmamns7uh50rwCOvVUm8ZFLHHTWpt4Yq+Z4Y8LJ4BqE4K2ACH78DuvfCQKeHU3l/2YawQfuogVg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791919196; c=relaxed/simple; bh=hLB9iIREQdRTkxWuZOfXaelUczjECboBhQUK9ZkYEUI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=rHNH++Qk9wFKUtBjIz6YWXAjx+B5EeBBF/BIrww0yK/7hHHF9FbFy+kIXZA3UujGcRcXp3k5KpwOCpuRREHeA5tILoOKZpoZpVRZsvZwC2LBKaFjv2BzsrrQGFHGMN+LKeg2XoU9A0KyXlPt4qI1u8iV8iDlKl1Vlwt7ZvYHNgc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=arWQXYwA; arc=none smtp.client-ip=209.85.210.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="arWQXYwA" Received: by mail-ot1-f47.google.com with SMTP id 46e09a7af769-81b54d0cb17so2614221a34.1 for ; Tue, 13 Oct 2026 12:19:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1791919192; x=1792523992; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=/M/UZry9pC3NdQaj6klwezszkFb09P0aYrxru7A7Vc4=; b=arWQXYwALKwVTSY/cFB0wzfvCEr+fcuR4lyGngU14kEp4keDpOy1+bfUP925b9BiG2 Uf+f7EdoedNpuYbn0aaOR3ZzGLOqvbLD73Qqs0q4lr8Q9U/NyWPMXly9ZQQwQnvysVro T70wszSGyTyphrxDOczwqiQ+AU3zt8GBVm4dUHnTVAEJtQiQYo6eRqIFRS2LMeGKPfkq WgzOwK2fjf/Lz25A51I0Ug3kyZCTzCbfCmE0PC5wpQ9xOObBusZQjH8GnpPn3JlcYCw8 OWO9vso2Q1E61kMYHK3gHedQieMAQ2a7g/mU4qnblhvwik9pleqNdOByzXp+4ORg/2D4 oN4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791919192; x=1792523992; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=/M/UZry9pC3NdQaj6klwezszkFb09P0aYrxru7A7Vc4=; b=hnUbbavIpwSHvv+mdnaHXXOPA6MRN5LAL8N+yUIiagDRx1ewNqxoD8kGkQBnQStSwx ordD8MS6LAZSwBXbB9InC8QoJR90o/7qBvTk/mQkj/eI2ozkPuQHMouxaYSls61zdyof 0sMO+3b/yF8MLwiqK4dvd+q3jVU1hMiocGm0+SKJdrbj8jDRIlVhGDTxTKJBjDuHl6gu fD11dm6tqfkO4ICZGnjU9qRCGsTJJ8ObC9cIhEufIqFL/Oh/s1e0G9HwyZzEoQKaf8Qi ODCyioyqJ5q0tdf4PpldNqqgjCZqs04HXzfL9o01HD1UkvD4kfm/i/zEIaK/KLK8y2sF fr2w== X-Gm-Message-State: AFq9FYKSB1Btv5n5u3CJMdBBkmITDYQaXVbpfL/qs6lkp+Z+ee/wGrPy tuTmo9WdIzXiwkZsZedxMgSco1kbbjNPr/wAHSyoOfyY11WMtIJA7YxSkYo2MoKk X-Gm-Gg: AYBFou2LlAQ0RueMDMMWLlUcS5yr09k8F17f5ZoXMbCy3rohSYNpW+6kJkKMCRQ44y7 9qbgnwMjSeZv/jQdmv0d5j7hT7A9/LX92TlK45dh7diUULwnyZRhEeKUmublxoMWKEdMZqMvNRe 7VTXNbMZTXdfLL8R8c0a8IewCIOWW+3sTatvuJKl4btVSWyiXHAUcxXmYX4RSrl6cIn0CNgFoO6 OWbvCrMJ5TBskY9I/BwtDXINHurdm7MrdnzJcrBuJ69jYeBrNc2x6WCuiD7scR0G8K+DRE6Yy6/ lLSAZywokdkjrmHwSBjsv+CcHyJrBapUUJ21LxAAMO+NhiRnFOmp85Z8AtTCTizP4dgcb78QRTI 1JS/7/ySxrASt6Mq5Omotzhzd8ajp1ZRd0AWj1HgJgNcVJkwqi3oQtwsQ/CWPoh1O5lFHg14Jm3 G0GLRzNZk42rsfakYK7e8DkicE+7TBLRsE78/TuiDcTqeN31gYFFSF7hPHEsmK7elsnOhtP15Us eYdlrDsR1CV85lnL+kECxt93FHeTmP7qnfRbLkW6pNvzUmnfR1yDniWfGdiq6eFC/1Nt7txELHU cgg3XmFMJRd1p69QyI7r3A6QwvGNHB09fofTZYOoS2gc/Xuijq77Iod/zhgjAgAxltm/b7kcVCx pMP3C1EiEDsoUEzgJL9wT X-Received: by 2002:a05:6830:6aeb:b0:7f6:705b:ffe7 with SMTP id 46e09a7af769-83095a338eamr12524842a34.14.1791919192556; Tue, 13 Oct 2026 12:19:52 -0700 (PDT) Received: from [127.0.1.1] (174-29-1-49.hlrn.qwest.net. [174.29.1.49]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-83039a3dfa1sm13280507a34.18.2026.10.13.12.19.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Oct 2026 12:19:52 -0700 (PDT) From: James Hilliard Date: Tue, 13 Oct 2026 13:19:48 -0600 Subject: [PATCH net v3 4/5] ptp: vclock: serialize extended samples with counter updates Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261013-ptp-vclock-sampling-v3-4-d3ee4ea62fc6@gmail.com> References: <20261013-ptp-vclock-sampling-v3-0-d3ee4ea62fc6@gmail.com> In-Reply-To: <20261013-ptp-vclock-sampling-v3-0-d3ee4ea62fc6@gmail.com> To: netdev@vger.kernel.org, Paolo Abeni , Jakub Kicinski , Richard Cochran , Andrew Lunn , Yangbo Lu , Miroslav Lichvar Cc: Eric Dumazet , "David S. Miller" , linux-kernel@vger.kernel.org, James Hilliard X-Mailer: b4 0.15.2 The extended and cross-timestamp callbacks sample the physical clock before taking the virtual clock mutex. A concurrent frequency adjustment can advance the timecounter and change its multiplier in between, so the older sample is converted using a different frequency than the one in effect when it was taken. Take the mutex before sampling and keep it held through the conversion. Retain timecounter_cyc2time() and its existing conversion window. A PHC sample need not advance the counter: for example, e1000e explicitly allows non-monotonic SYSTIM readings. Treating a slightly older sample as a forward delta would instead advance virtual time by nearly a full counter wrap. This race was found by code inspection of the virtual clock sampling paths. Fixes: f0067ebfc42b ("ptp: add gettimex64() to virtual clocks.") Fixes: 21fad63084c2 ("ptp: add getcrosststamp() to virtual clocks.") Signed-off-by: James Hilliard --- drivers/ptp/ptp_vclock.c | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) diff --git a/drivers/ptp/ptp_vclock.c b/drivers/ptp/ptp_vclock.c index eea207e5a889..6675466bc307 100644 --- a/drivers/ptp/ptp_vclock.c +++ b/drivers/ptp/ptp_vclock.c @@ -113,20 +113,18 @@ static int ptp_vclock_gettimex(struct ptp_clock_info *ptp, struct ptp_clock *pptp = vclock->pclock; struct timespec64 pts; int err; - u64 ns; - - err = pptp->info->getcyclesx64(pptp->info, &pts, sts); - if (err) - return err; if (mutex_lock_interruptible(&vclock->lock)) return -EINTR; - ns = timecounter_cyc2time(&vclock->tc, timespec64_to_ns(&pts)); - mutex_unlock(&vclock->lock); + err = pptp->info->getcyclesx64(pptp->info, &pts, sts); + if (!err) { + u64 ns = timecounter_cyc2time(&vclock->tc, timespec64_to_ns(&pts)); - *ts = ns_to_timespec64(ns); + *ts = ns_to_timespec64(ns); + } + mutex_unlock(&vclock->lock); - return 0; + return err; } static int ptp_vclock_settime(struct ptp_clock_info *ptp, @@ -152,20 +150,18 @@ static int ptp_vclock_getcrosststamp(struct ptp_clock_info *ptp, struct ptp_vclock *vclock = info_to_vclock(ptp); struct ptp_clock *pptp = vclock->pclock; int err; - u64 ns; - - err = pptp->info->getcrosscycles(pptp->info, xtstamp); - if (err) - return err; if (mutex_lock_interruptible(&vclock->lock)) return -EINTR; - ns = timecounter_cyc2time(&vclock->tc, ktime_to_ns(xtstamp->device)); - mutex_unlock(&vclock->lock); + err = pptp->info->getcrosscycles(pptp->info, xtstamp); + if (!err) { + u64 ns = timecounter_cyc2time(&vclock->tc, ktime_to_ns(xtstamp->device)); - xtstamp->device = ns_to_ktime(ns); + xtstamp->device = ns_to_ktime(ns); + } + mutex_unlock(&vclock->lock); - return 0; + return err; } static long ptp_vclock_refresh(struct ptp_clock_info *ptp) -- 2.53.0