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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1688816133; h=from:from:sender: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=UqJlduoTQOyBIFI9wT/oLtRjyLfk3jWkAwjS3WzqvZw=; b=geKZVCWkPTCs53MeUoMTC86Nq2b9b4uFKRRKqwUVMsX05Fk5fwt6DN6MZQFS6K/cTbX2C0 cSfyU7VJJLRvnLMjIjnVQzuayj/Rr5KMPkBDzAOfc47QeDTDthRogQ0bN000VyR8oQVq2v RWv3m8wqtn0Reb2c+U2syGA52WLSM/4= Received: from [2a02:8108:8980:2478:8cde:aa2c:f324:937e]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1qI6Dm-0004GA-MM; Sat, 08 Jul 2023 13:35:26 +0200 Message-ID: Date: Sat, 8 Jul 2023 13:35:25 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: Fwd: Memory corruption in multithreaded user space program while calling fork Content-Language: en-US, de-DE To: Andrew Morton , Linus Torvalds Cc: Suren Baghdasaryan , Bagas Sanjaya , Jacob Young , Laurent Dufour , Linux Kernel Mailing List , Linux Memory Management , Linux PowerPC , Linux ARM , Greg KH , Linux regressions mailing list References: <5c7455db-4ed8-b54f-e2d5-d2811908123d@leemhuis.info> <2023070359-evasive-regroup-f3b8@gregkh> <2023070453-plod-swipe-cfbf@gregkh> <20230704091808.aa2ed3c11a5351d9bf217ac9@linux-foundation.org> <2023070509-undertow-pulverize-5adc@gregkh> <7668c45a-70b1-dc2f-d0f5-c0e76ec17145@leemhuis.info> <20230705084906.22eee41e6e72da588fce5a48@linux-foundation.org> From: Thorsten Leemhuis In-Reply-To: <20230705084906.22eee41e6e72da588fce5a48@linux-foundation.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-bounce-key: webpack.hosteurope.de;regressions@leemhuis.info;1688816133;4ce8089e; X-HE-SMSGID: 1qI6Dm-0004GA-MM X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 015A380017 X-Stat-Signature: rwqermmdguxn36azndiaayxxzpq75nqz X-Rspam-User: X-HE-Tag: 1688816132-230783 X-HE-Meta: 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 YVWjJGq5 XGNqyxWubsHhwo4C0DO9D+rI37+JJE+4tLXQwfCzTPjw/C9qvEuf98xc3ym6ZTVSHQd70iQlclqKUbUVkGxf4gqUy8QP41hRz8F3KdBN+DYybFULMgyLp24vWY8vP0ezxcd2lBNye5JwbAMQCBM+QDSotQDy4Gch4tUNCU38RwIq+L1CNoYkxDTMe5O8C++XtAln6f4E1NtKpwXCFZnN64JkqNN86gbaV+XHbunnEfLlImn9Vk+JuRNXQfGMLTaEaZQ6U5yItheW8A8Te3EOTzFI0oFPf1k1y/fWWFNzRwZRjUa5w76W53Dt5FFvnKWqNwA4DxrbYtc9Vqm1Y9ZvrmMC0tMj8cHohMcwgWKz0dQputXgw8ZLa+q9XHyyOhahQbJ6c X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: [adding Linus to the list of recipients to ensure the fix makes it into -rc1 (and can finally be backported to -stable). Linus, here is the backstory, as I assume you haven't seen this yet: CONFIG_PER_VMA_LOCK (which defaults to Y; merged for v6.4-rc1 in 0bff0aaea03 ("x86/mm: try VMA lock-based page fault handling first")) sometimes causes memory corruption reported here: https://lore.kernel.org/all/dbdef34c-3a07-5951-e1ae-e9c6e3cdf51b@kernel.org/ https://bugzilla.kernel.org/show_bug.cgi?id=217624 The plan since early this week is to mark CONFIG_PER_VMA_LOCK as broken; latest patch that does this is this one afaics: https://lore.kernel.org/all/20230706011400.2949242-3-surenb@google.com/ But that change or something similar hasn't reached you yet afaics; note, this is the second patch of a series with two patches] On 05.07.23 17:49, Andrew Morton wrote: > On Wed, 5 Jul 2023 10:51:57 +0200 "Linux regression tracking (Thorsten Leemhuis)" wrote: > >>>>> I'm in wait-a-few-days-mode on this. To see if we have a backportable >>>>> fix rather than disabling the feature in -stable. >> >> Andrew, how long will you remain in "wait-a-few-days-mode"? Given what >> Greg said below and that we already had three reports I know of I'd >> prefer if we could fix this rather sooner than later in mainline -- >> especially as Arch Linux and openSUSE Tumbleweed likely have switched to >> 6.4.y already or will do so soon. > > I'll send today's 2-patch series to Linus today or tomorrow. That afaics did not happen until now. :-( This makes me regret that I did not CC Linus earlier. I always feel like a snitcher when I do that. But in retrospective it seems it would have been the right thing to do given the problem, as I suspect Linus would have quickly applied the patch or marked the feature as broken himself. So thx to this (and a handful of earlier, similar situations) I now fully made my peace with feeling like a snitcher (I always knew that it's kinda part of the position). When something in me says "Ick, this looks bad to my untrained eyes" I'll immediately CC Linus. Linus, if I take things to far just let me know. But I assume you get a lot of mails and won't mind a few more. Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr If I did something stupid, please tell me, as explained on that page.