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 11CD33A7834; Mon, 9 Mar 2026 12:23:53 +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=1773059034; cv=none; b=QMn8snAqNI07Dc9XNo8ZkSa6+7I2bQ/F/T7m1h+0dTqICjGDzoXkogVt725+pp2roW5LNCzapvmcynufTj7ZnbaDzpX44f8YKHU1JVjVX4JeKrbp/xyb9iFfq09GwBmuzArvexptrCVCBNxaooVv/mk56y81yzZ9qsqnnU2Cuh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773059034; c=relaxed/simple; bh=Py+g6qnSgfEWX6Iy57JwP3p1Ze1RcHqTVF7eH+A0Jhk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qxnc78KH1VCZkM4/Qr2YTqTyik039zIQwnnXXxnjo9guFlrsw3Jq6lgZOQyoz2j8t/feVFdnNn1N3XreOau6QHugJaWdjbVR9kwACJ7h/pPU463AJmAoCvwGVyXoP3sfsGjTRaqjSOYTvr1/gwJnwKPTBmv/vsP5+EmkOk/yD4A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PvW4+5jG; 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="PvW4+5jG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 11CD8C2BC9E; Mon, 9 Mar 2026 12:23:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773059033; bh=Py+g6qnSgfEWX6Iy57JwP3p1Ze1RcHqTVF7eH+A0Jhk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=PvW4+5jGrvqEwqTJgwKyHWnHCD4CDRJ/u0vWGwgMRhHQYFXpnPbSqrG+0BB/qCigK 0rjDo7Wbe/D/FtdJEth+OLeRQNISEeO9zfkJDjL0iFSQ+MjzesPDa+YhQCM7uRjj8M bYI3GGrKrQhaLcBsA1wbHipEKP6czfMaWYy1dFu9rs7SgNLeHk6pmbyiiQatCeYSK+ nVBxHPOid2BywQf1QS/xk8+7vM5bjB36WH+hi+GGkOaR1/M1TneLJI/yLTeiaEe9kR 505lQlqcTSIio85UBYbLQL7OSLtFP1syJxfq+LY8AKNvuB5it3nCV0QLaqS+6X+15c KXgvvhib5oFeg== Message-ID: <0ae4d678-5676-4523-bae3-5ad73b526e27@kernel.org> Date: Mon, 9 Mar 2026 13:23:45 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: Stalls when starting a VSOCK listening socket: soft lockups, RCU stalls, timeout Content-Language: en-GB, fr-BE To: Thomas Gleixner Cc: Peter Zijlstra , Jiri Slaby , Stefan Hajnoczi , Stefano Garzarella , kvm@vger.kernel.org, virtualization@lists.linux.dev, Netdev , rcu@vger.kernel.org, MPTCP Linux , Linux Kernel , Shinichiro Kawasaki , "Paul E. McKenney" , Dave Hansen , luto@kernel.org, =?UTF-8?Q?Michal_Koutn=C3=BD?= , Waiman Long , Marco Elver References: <863a5291-a636-47d0-891c-bb0524d2e134@kernel.org> <20260302114636.GL606826@noisy.programming.kicks-ass.net> <717310d8-6274-4b7f-8a19-561c45f5f565@kernel.org> <87zf4m2qvo.ffs@tglx> <47cba228-bba7-4e58-a69d-ea41f8de6602@kernel.org> <87tsuu2i59.ffs@tglx> <7efde2b5-3b72-4858-9db0-22493d446301@kernel.org> <87qzpx2sck.ffs@tglx> <20260306152458.GT606826@noisy.programming.kicks-ass.net> <87ldg42eu7.ffs@tglx> <87h5qr2rzi.ffs@tglx> <87eclu3coa.ffs@tglx> <87v7f61cnl.ffs@tglx> <57c1e171-9520-4288-9e2d-10a72a499968@kernel.org> <87pl5ds88r.ffs@tglx> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: <87pl5ds88r.ffs@tglx> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Thomas, On 09/03/2026 09:43, Thomas Gleixner wrote: > On Sun, Mar 08 2026 at 18:23, Matthieu Baerts wrote: >> 08 Mar 2026 17:58:26 Thomas Gleixner : >>> So I'm back to square one. I go and do what I should have done in the >>> first place. Write a debug patch with trace_printks and let the people >>> who can actually trigger the problem run with it. >> >> Happy to test such debug patches! > > See below. > > Enable the tracepoints either on the kernel command line: > > trace_event=sched_switch,mmcid:* > > or before starting the test case: > > echo 1 >/sys/kernel/tracing/events/sched/sched_switch/enable > echo 1 >/sys/kernel/tracing/events/mmcid/enable > > I added a 50ms timeout into mm_cid_get() which freezes the trace and > emits a warning. If you enable panic_on_warn and ftrace_dump_on_oops, > then it dumps the trace buffer once it hits the warning. > > Either kernel command line: > > panic_on_warn ftrace_dump_on_oops > > or > > echo 1 >/proc/sys/kernel/panic_on_warn > echo 1 >/proc/sys/kernel/ftrace_dump_on_oops > > That should provide enough information to decode this mystery. Thank you for the debug patch and the clear instructions. I managed to reproduce the issue with the extra debug. The ouput is available here: https://github.com/user-attachments/files/25841808/issue-617-debug.txt.gz Just in case, the kernel config file that was used: https://github.com/user-attachments/files/25841873/issue-617-debug.config.gz Please tell me if it is an issue to download these files from GitHub. The output file has 10k+ lines. Cheers, Matt -- Sponsored by the NGI0 Core fund.