From nobody Thu Sep 26 22:37:43 2024 X-Original-To: net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4XF7lW3Spvz5X77S for ; Thu, 26 Sep 2024 22:37:43 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R11" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4XF7lW2G3Yz4RQ7 for ; Thu, 26 Sep 2024 22:37:43 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1727390263; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UmAttanythG00rJ1ljK7kSRf4FAjdUOU2RFq0PlUBA4=; b=AZksHbI7QebGrU+BSvt5Yf1weBEd9BLApahn1P3V48M0EQkq7ITh4HxpDshnvuEsSNXb+4 MtAy69e0JKhsSLFVeOuAk/+esLnYql4cM8X2JECYJBO0UEyZ6WN13BOJIhpMOaS24LAM9J FXvss+pcjSgWEUG91bYW3iWEv3bnbUNv4P3WP4WfFH6KbWTP/mU/u+qSdqRd2wuG1lyE4D 87fPwPt9lnub8CAjhrA5oSrbHVHsbZQgrUKjqO+9Lh8/oDLyPr8c1ACyzceWxhXVjCZif0 bJ+jPYpPrSp9VH7bHscDvyuCHSCMx9MS2YJW4fNgR5DiDZeBhgHSTHIx9JuUow== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1727390263; a=rsa-sha256; cv=none; b=ff5jPesRaaf8RNFpaO/pbHK343u2ycQxFV9xGb5euoSkTIiikQUEn6wsmM3F7TOBlzlpoC R9GeOmGhXZPh6crSKnVM5QxzGFRm0Xas5i8iHPKoeMLEaWfTyEIFyGPtPaqoOkCRJjO8T3 E0b/HqKMhK8KW5+JRNZQzBh4Ow8iE21U1NRWxcNH2kgQQayVWdZYdJBRrgDLKyioHU7BGo HqSD6mqn9OFXr1YloktQwID3CaHXZlz2hzB4dv1/dZfqyhVgjcCvQLSvPmDyPW8dzrFA0d Idin9pP7hj4d5lrktXqpc8oW2J7bngUGqTMQ8ha1D1S+UOUN2xxI/KAIa2spaA== Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4XF7lW1t3vzF4J for ; Thu, 26 Sep 2024 22:37:43 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 48QMbhcr039473 for ; Thu, 26 Sep 2024 22:37:43 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 48QMbhEU039472 for net@FreeBSD.org; Thu, 26 Sep 2024 22:37:43 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 281560] gve (4) uma deadlock during high tcp throughput Date: Thu, 26 Sep 2024 22:37:43 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 14.1-RELEASE X-Bugzilla-Keywords: vendor X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: gallatin@FreeBSD.org X-Bugzilla-Status: Open X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: net@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@FreeBSD.org MIME-Version: 1.0 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D281560 --- Comment #12 from Andrew Gallatin --- Comment on attachment 253834 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D253834 procstat_kka Are we absolutely certain that this is a deadlock and not a livelock? If y= ou look at network counters, etc, seconds apart do you see any movement at all= ?=20 Is that iperf killable? I'm asking this because while most of the uma locks are in the allocation p= ath, but some are in the free path (0 100421 kernel gve0 rxq 8=20= =20=20=20=20=20=20=20=20 mi_switch+0x171 __mtx_lock_sleep+0x1ba __mtx_lock_flags+0xe1 zone_put_bucket+0x75 cache_free+0x2da uma_zfree_arg+0x21c mb_free_ext+0x126 m_free+0xda m_freem+0x48 tcp_do_segment+0x1e6b tcp_input_with_port+0x1135 tcp_input+0xb ip_input+0x2ae netisr_dispatch_src+0xad ether_demux+0x17a ether_nh_input+0x3f8 netisr_dispatch_src+0xad ether_input+0xe5), and it appears that the iperf thread that holds that zone lock is actually doing something. I've seen degenerate, live-locking, behavior in the past when allocations a= nd frees overwhelm the per-cpu caches and there is contention for the zone loc= k.=20 Throughput drops by 80% or more, and the system becomes incredibly sluggish= and its easy to think it is a deadlock. --=20 You are receiving this mail because: You are the assignee for the bug.=