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Wed, 5 Jul 2023 07:09:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57875C433C7; Wed, 5 Jul 2023 07:09:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1688540940; bh=KNHJu+0CLU4ZCQdLgEFri5D+Z9BwIrdluwuvuUeNttE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tKdIALsR0dMkHa9DJuKzvIPN6d8h9dFfEniOOt9bWgEKNcQIdf7any+sOkoPLEKea +95s2KQ452fHNF4mzK3LiP0iF8hrCJ186zokGs38t/pxGUAu4cT3Fhxu8f4UEm1j6P LCmtLDw3WijgFusqsM7zA87m4MVC7ID+D/hmFgPI= Date: Wed, 5 Jul 2023 08:08:58 +0100 From: Greg KH To: Suren Baghdasaryan Cc: Andrew Morton , Linux regressions mailing list , Bagas Sanjaya , Jacob Young , Laurent Dufour , Linux Kernel Mailing List , Linux Memory Management , Linux PowerPC , Linux ARM Subject: Re: Fwd: Memory corruption in multithreaded user space program while calling fork Message-ID: <2023070509-undertow-pulverize-5adc@gregkh> References: <5c7455db-4ed8-b54f-e2d5-d2811908123d@leemhuis.info> <2023070359-evasive-regroup-f3b8@gregkh> <2023070453-plod-swipe-cfbf@gregkh> <20230704091808.aa2ed3c11a5351d9bf217ac9@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Queue-Id: 7622DC0021 X-Rspam-User: X-Stat-Signature: 5yy14feeyzytwm61tiz9hn5ztcxe4mtg X-Rspamd-Server: rspam01 X-HE-Tag: 1688540942-799100 X-HE-Meta: U2FsdGVkX19TUnkFTdxtSXC/AE5H787uucpORxoQNRKmZV/u45jp6rp9K3gTVR5mD0OiS2DkKw96pzscAeEEjiWTLCrkTe9lteeZdYAqVOPT1rVW9PgM69hQxrVu6DneI08hZfKnye+tOEwXLtb7OD4gMtC9rZm7og08UHvxMhcHIozpP/PBU6GHWOu0aH5kfM6v6Ep01PX27XUNDV78F4L+Nt9jpef1y01Vvpb9r2/k9KN2RCYMQCZ7JA9qfMpZWt/qW5pStXOlODLd0NGRNoPNIIB3uAW2V5f676cj8jz2swkU+1qt32iBu22LUP6Zc4NevKibHRLSmuaW0SxtJ0HWMXkqC68Bdc2xC1DA973GC9aSNwaa4KH68tH8KWo/SYNWQWATTyi031+BEKle8HZM0ehr+qLYP0xQHSyZtKi+bzKRe7JKeVFpkniIGIYJCBti7fjox8HgoGmV4gO1gvcu7tCHSBHsYQNRAhPZ7CKggotdS2IlwqP+iJenmn3HjiMZ/jixj7HoR/YbmQN1cycHLo4sXD6UDKF12+4SXWgjqrcmm6jXzjYPX77Wh1SWE0XJxhoqlkA8ElDU4scITJjdu476sgib1B4Qes1gn8WllrSKoqL9REFf3clvO1yBQN4dW4lEOJdh1XxtriqApndgcZDextbEJ/uOx7WW+6O1NikdNU0Ig9LtRX9N/RwnrqBvd9NfZ3m9Om0TVNEnkTjUCSDiipaXzPupQKY2GDRg4wcw9dtelUprdtrvSUtrg5UfZkLNVxNUQDWx/8LUPgpE8CjYIb70GBvBrQcxBHTyHBsQJ17ZTE5+WCAk6GZf07ziG22z49bK9A3wlXaRC0tigmDPZ4ycxXt7xWVtVAzODq47m7YH6cicmp4Y0bWa0GtbhhOJMjHggqLNEtqwnLumjAqNgID9Z24LjxwqnqOuRQch6/cGgnuRnCANwd3TaeV5z8vgmX2LmL/uAp/ /JzISrL7 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 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: On Tue, Jul 04, 2023 at 01:22:54PM -0700, Suren Baghdasaryan wrote: > On Tue, Jul 4, 2023 at 9:18 AM Andrew Morton wrote: > > > > On Tue, 4 Jul 2023 09:00:19 +0100 Greg KH wrote: > > > > > > > > > Thanks! I'll investigate this later today. After discussing with > > > > > > > Andrew, we would like to disable CONFIG_PER_VMA_LOCK by default until > > > > > > > the issue is fixed. I'll post a patch shortly. > > > > > > > > > > > > Posted at: https://lore.kernel.org/all/20230703182150.2193578-1-surenb@google.com/ > > > > > > > > > > As that change fixes something in 6.4, why not cc: stable on it as well? > > > > > > > > Sorry, I thought since per-VMA locks were introduced in 6.4 and this > > > > patch is fixing 6.4 I didn't need to send it to stable for older > > > > versions. Did I miss something? > > > > > > 6.4.y is a stable kernel tree right now, so yes, it needs to be included > > > there :) > > > > 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. > > Ok, I think we have a fix posted at [2] and it's cleanly applies to > 6.4.y stable branch as well. However fork() performance might slightly > regress, therefore disabling per-VMA locks by default for now seems to > be preferable even with this fix (see discussion at > https://lore.kernel.org/all/54cd9ffb-8f4b-003f-c2d6-3b6b0d2cb7d9@google.com/). > IOW, both [1] and [2] should be applied to 6.4.y stable. Both apply > cleanly and I CC'ed stable on [2]. Greg, should I send [1] separately > to stable@vger? We can't do anything for stable until it lands in Linus's tree, so if you didn't happen to have the stable@ tag in the patch, just email us the git SHA1 and I can pick it up that way. thanks, greg k-h