From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta1.migadu.com (out-181.mta1.migadu.com [95.215.58.181]) (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 9386226ACD for ; Sat, 15 Jun 2024 17:49:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718473784; cv=none; b=K841kIbEFYCxvtqHuXiBf3JbANGriENTaQXEVe62fT0gyTuAnFb+0GECIl4PBpwxsX8dgVtJr26tmj7POBHpSGKZ1XwtlUJ/nvbPDdF2mhXkaX7A2mKBjTtVDcZ47ednlNVlOBff+E0xiIgJ+6u4hHnLSASJ1xVbiGqHSBMI0B0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718473784; c=relaxed/simple; bh=shQFVXgquplzSvph1NcgptaRdys0rYDQT6sCCNqT6LI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=r7SW4+mE4erJtAeCwUvkHA9XwfX/vilUe0tK1aAu7b3W47ExG0RKqA4rX7lPPzoH5XvmRZPmEmCDRn4v+Sjq/THWwycB31l2v4A3q67WXyDHgeRwnHc3NwAnrqiTGYNrmMBB5g4KCAwtOty3FDppXfO3Wj3zpOrhVlRck3ZzGcE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=qM/UA3cR; arc=none smtp.client-ip=95.215.58.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="qM/UA3cR" X-Envelope-To: alexei.starovoitov@gmail.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1718473779; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=shQFVXgquplzSvph1NcgptaRdys0rYDQT6sCCNqT6LI=; b=qM/UA3cRI4LYGDuICsq2541PEbFrpZVEz8safvr4eehzE1P1DTq97BKCE4PE9pF67zd8JR /YzLr0yDoMKl0sAlxEWolH0Dp45TRJIPVRtbtBvc/2A3roQp7pOJbSUkhbggGbqyVasDPc vbcl3ywd7PwpWVA791spHaAxstj9cJY= X-Envelope-To: zacecob@protonmail.com X-Envelope-To: bpf@vger.kernel.org Message-ID: Date: Sat, 15 Jun 2024 10:49:31 -0700 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: rcu_preempt detected stalls related to ebpf Content-Language: en-GB To: Alexei Starovoitov , Zac Ecob Cc: "bpf@vger.kernel.org" References: <-P_rTwSVX1lEiqRGA2drBZcQM24fbnVw4OBcVUrZ4bwPHBQ9QhFHJeWrHmImV3UxR6YqbRdkKXgVHHfNck-54u8Q0QSK6Qi4EWzxr9PVPSE=@protonmail.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yonghong Song In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 6/15/24 9:59 AM, Alexei Starovoitov wrote: > On Sat, Jun 15, 2024 at 12:09 AM Zac Ecob wrote: >>> I reduced the reproducer to the following: >> Thank you for minimising the repro - I didn't think to do it myself. Apologies. >> >>> The verifier doesn't process the (s8) instruction correctly. >> I took a further look out of curiosity and managed to properly crash the kernel. I think it might have security implications? >> I haven't attached a repro for this because of such (though I could perhaps email it directly?). >> >> Not sure how best to precede? > Pls focus your efforts on fixing the bug. This is the fix: https://lore.kernel.org/bpf/20240615174621.3994321-1-yonghong.song@linux.dev/ Zac, could you test it in your environment?