From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793907006; b=dWNx4/B3g9EWNTwYOSU2vxDXS0b2fhXwUDez2zITRWe2FJTYQ9bG6tv5VhcH6+CZ92px EG+9BXYEpelgHu4KN0pv9bRO8rCio6bUHUU5ljDGXkzE0bUXLiHeiYKL9ewb79DVnUTbq ONKOUGvFS33MECjU3er13YhCdxl1YcZfZOeuvGSBwbuMi5bUx1R5issc2TdtJtHuMyV8B csMtsBby/40HKEHXlhqpk0Tkm6+UuAElkf4RJvNjfIS+bKzuzk+FEwM7Qv/tSLviwUp/Z sPficZur/doDTiRiovdRvGCnPDm4yFahE8/84PtWF7mls5bTQjIDvQpug8wmJ5Yn41Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793907006; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=hsy7qPadddcHp1yz4RskpjuPCs9z+iyUZQjRxWR0tno=; b=Q8Swup0DCIWAl4qVWDGt73vWJ7tMz6Oa8f8P46S269G8VD4aH/ASV5+oaGidM6vd2hEU 5r9ZhhR8vOrNa/DPVygsThhw2le1/j31Lgtvtb9DB4or/qkEnsKToBYAzQGd+qITQ1Q0N 3JsyRI/gwiCsctRJ2pWIco6Ygy4VE4OKbxB79ApdpMPw7k8gX8kcMWQERNSbxu5kYqp5D Z5m2E8vo4g71LlK5aqDKJ29sQf25970FtdNypwLVyU/lCaIxk9SB6ZoLqbV0hgChPicwt +fbTUYcJdVtAMLHdsLEpU23vWmrYE7meCMTOjpHd2MUHPr3q5XUYy862GC8zQihxHfA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=n1pRV84z; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A88D8606D823; Thu, 5 Nov 2026 19:30:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=n1pRV84z Received: by smtp.kernel.org (Postfix) with ESMTPSA id D006D1F000C1; Thu, 5 Nov 2026 19:30:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793907005; bh=hsy7qPadddcHp1yz4RskpjuPCs9z+iyUZQjRxWR0tno=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=n1pRV84zJKUUtgUv1TYLImkQPkvmaqLjvwYZrx2oyTCwObzhdrQFqivFQJG2KSTyQ eTIbvYnu/am2gKJ0v2gg99xx3HGgCRhK3jtKYYV/hEN32FiOkUwOd5qfCd1EvNlRbU /wDWKpQlTW9sg368vKkBt979aVtHTwB7aqgs1lZ3cZ7yuOwpmH/5K72S+3ZXzvHDZJ zCVaJA/NGoQ3f5O/ZIg5OD8CZV38pYz/7PwHfRkFO2BSCEBpwk5KemMFv7yST4FY/7 ke1edsHonMb+SJ+aejvls7v7xGnvSnNsG3bwmscXuAXx4DTCqwdtiudcPMpO6x6AMq QMz7+TNSVPVMQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RESEND v2 37/51] proc/vmcore: don't let vmcore_cleanup() run twice at once Reply-To: sashiko-reviews@lists.linux.dev To: "Christian Brauner" Cc: "Linus Torvalds" , "Jann Horn" , "Josef Bacik" , "Chris Mason" , "Jeff Layton" , NeilBrown , "Eric Dumazet" , "Thomas Gleixner" , "Al Viro" , "Jonathan Corbet" , "Christoph Hellwig" , "Greg Kroah-Hartman" , "Joel Granados" , "Kees Cook" , "Jan Kara" , "Jan Kara" , linux-s390@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, linux-m68k@lists.linux-m68k.org, linux-serial@vger.kernel.org, "Takashi Iwai" , linux-ext4@vger.kernel.org, "Chuck Lever" , tytso@mit.edu, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261104-work-procfs-bugfixes-v2-37-021c84d852e0@kernel.org> References: <20261104-work-procfs-bugfixes-v2-0-021c84d852e0@kernel.org> <20261104-work-procfs-bugfixes-v2-37-021c84d852e0@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 05 Nov 2026 19:30:03 +0000 X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > vmcore_cleanup() has a single caller, fadump's release_mem_store() on > powerpc. That checks fw_dump.dump_active without a lock and calls > vmcore_cleanup() without one, and kernfs only serializes the writers of > one open file. So two tasks that write to > /sys/kernel/fadump/release_mem through different files run > vmcore_cleanup() at the same time. >=20 > The first one removes /proc/vmcore and waits for its readers in > proc_remove(). The second one finds the entry already unlinked, returns > from proc_remove() right away and frees vmcore_list, the ELF headers > and the device dumps while those readers still walk them. Or both of > them free the same lists at once. >=20 > Serialize vmcore_cleanup() with a mutex of its own. It can't be > vmcore_mutex, removing /proc/vmcore calls release_vmcore() which takes > it. The second caller then finds nothing left to free. >=20 > Reported-by: Chris Mason > Fixes: b500afff11f6 ("fadump: Invalidate registration and release reserve= d memory for general use.") > Cc: stable@vger.kernel.org > Signed-off-by: Christian Brauner (Amutable) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261104-work-procf= s-bugfixes-v2-0-021c84d852e0@kernel.org?part=3D37