From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 51D5B233924; Sat, 3 Oct 2026 14:15:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791036902; cv=none; b=NVnc1IXbzCF39A+qNdP2yzxIVXulwGiLu6x28hcmNffxzIYE5TZbFjkZoN7O3MsxOiTw6HN4iSP4oWvY+fMeiYEKuz/FDjSs1e1/aow6qG5V63irrvjeXDfEGa2CSq79eCI4KUaV3VjkTWhSu8mD/nqkYevQ277i+MLS54tJHGw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791036902; c=relaxed/simple; bh=Eqg+oh/MF7tdokAAzxlhOtEKqj7GnyJkzYGBCi3uSbg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ty58DJIc2w6se5ReoLXK3NfLaak+WxFOcwws7P2ymdnAQFGJX9+n8fknpSubdAQK43+DUKSSccEf3bYMBeiGGY+tPy7csyudjfVgW1IU1rkBHWAF2MQa90htzr8rPLQB1TEvowGefhShUfPDklxhVQQDoxraSvCk8jU6CWedb1Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SNRktYnE; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SNRktYnE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7BE61F0089B; Sat, 3 Oct 2026 14:14:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791036900; bh=L3O+SY14NmcYs4JOqo1ht8ryDCyOse2Feg9y7x3ofFA=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=SNRktYnEK7R9VzzxgyiWbfu//bLlEPx/3iTGJPYJdLhai16FG6aTFMGU7JaT84h4M BZEiUB1axFm6wSUaqikzT6RE1ZoaRJeioaFzRzmxOJRsIJlbJw0kxd+cc4GgPEiLRQ ow4txwe8rn5oRcUGBeG620aug3LlerZYFAaHdf8pbsuss0xkr6v2qqbCHbeIOslQpG b2+sCRTcAHTYIaiKX1n/ZSzg0I3Is3olC9np5K1rB2CFpQPyrr7gJlAEG+6v2h+m83 6zId4Q7f2KOeGRM+tXszpsKBfd/MDgXM/XrYQCVCtnJEGCzXCNX09K1Cy1vIQh6UE8 mWCea77kqo/uw== Message-ID: <3c5b9d1e-5ed4-4bd1-b532-39f2d4612965@kernel.org> Date: Sat, 3 Oct 2026 16:14:49 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [REGRESSION] secretmem: SIGBUS on memfd_secret() pages while perf record runs To: Ameer Hamza , ljs@kernel.org, rppt@kernel.org, peterz@infradead.org Cc: akpm@linux-foundation.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, regressions@lists.linux.dev, stable@vger.kernel.org, 4ncienth@gmail.com, sashal@kernel.org, alexander.motin@truenas.com, caleb.stjohn@truenas.com References: <20261002175651.811343-1-ameer.hamza@truenas.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/2/26 19:56, Ameer Hamza wrote: > Hi, > Hi! > Since commit 97d34aa65c29 ("mm/secretmem: properly account locked > pages"), in v7.3-rc2 and the 6.18.52 and 7.2.5 backports, touching a > memfd_secret() page for the first time fails with SIGBUS while the > same user is running perf record, and read() into such a page fails > with EFAULT. This happens for root as well as for an unprivileged > user running its own perf record. It reproduces on v7.3-rc4 and > 6.18.52, and the same test passes without the recording or with the > commit reverted. Thanks for the report! May I know whether this problem was found by (a) A real workload (b) A test case (c) Complains by some tooling I am asking, because so far I was under the assumption that secretmem isn't heavily used in the wild. -- Cheers, David