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 1B9D82E8DEB; Sat, 19 Sep 2026 17:07:22 +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=1789837644; cv=none; b=FB4qyiqeQ48URXkJ3OVwhBJFTBcdtFKoLcyNFw6Ul1Wa0S0/DmZeTgvaU2NfDkzljC43MhxCUohfecD1wrU1+W/j3mevNTCP+04ylwS4IYchrCUVpMPE8927U55+JrYvoLioFNd1Nk1imEgHhTToNjUt6xKLV4Y2Gp28x6Xg+4s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789837644; c=relaxed/simple; bh=8rBsJdt96krUf8mZ3ofhFwaD0Oj6wvryd53TwKn+rmY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fu/NDbMgObBn8sxXaL4NjrfeqSdMyCWPezL9usoO/emM+CQiRRX9/j1+R7Dh9wiP/ATPu/OqOkw4pClD1y9bxv9ssowbEv4cw9gjVilomOR38YX1DAu+Z7vNjXFBcvsrWGN3B7mHr2cbhkgOswtl1zuCKqYw5LtdsP9tsh36o4E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OH18l8d7; 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="OH18l8d7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63AC91F000FF; Sat, 19 Sep 2026 17:07:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789837642; bh=oPt6k1SU2rZ5GUciEked3ObqN8vGIC3bKt2iePvZ4ec=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=OH18l8d76tvib9jY4wRTNxx2/Jto2mRnBazas4Cod9TUf/6Aor9FgRpd9vTFwNQaj WRaJKG6WlpReMNWjBp+Oh4I7K5O2SRvtrJOEEKwaHJI7mnfhrXAh+tedR9gDL7fJte llku0Okd2vuFnQxq/UyefLQv4wKA0xNT6lDy+TCRCEZUKqkvyScwPYb2PmNpyzCUns E1CKRv3MBScyOzN8dk044SQ6XiYvOV713f+yS46frW9gsMx2gW+UBMlycnTblLZzNO pyNC45nQ5CkVBA0VOnKzlkfQ41lqmU2I4BIIkFjy/Mj3Yo+AzmtUbVx3ckIdwQcRNI pdFiFTDEVlGow== From: Sasha Levin To: "Barry K. Nathan" , Greg Kroah-Hartman , stable@vger.kernel.org, Kuniyuki Iwashima , Eric Dumazet Cc: Sasha Levin , patches@lists.linux.dev, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, linux@roeck-us.net, shuah@kernel.org, patches@kernelci.org, lkft-triage@lists.linaro.org, pavel@nabladev.com, jonathanh@nvidia.com, f.fainelli@gmail.com, sudipm.mukherjee@gmail.com, rwarsow@gmx.de, conor@kernel.org, hargar@microsoft.com, broonie@kernel.org, achill@achill.org, sr@sladewatkins.com Subject: Re: [PATCH 6.12 0000/1102] 6.12.111-rc1 review Date: Sat, 19 Sep 2026 13:07:17 -0400 Message-ID: X-Mailer: git-send-email 2.53.0 In-Reply-To: <49dc2e4f-7a94-430c-8b02-6f3d422222f3@pobox.com> References: <20260917151539.408551884@linuxfoundation.org> <49dc2e4f-7a94-430c-8b02-6f3d422222f3@pobox.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit On Sat, Sep 19, 2026 at 03:54:25AM -0700, Barry K. Nathan wrote: >> [   98.363843] RTNL: assertion failed at net/ipv6/mcast.c (1014) >> [   98.363896] WARNING: CPU: 6 PID: 961 at net/ipv6/mcast.c:1014 __ipv6_dev_mc_dec+0x17b/0x190 [ipv6] > I bisected it to this patch: > ipv6-mcast-don-t-hold-rtnl-for-ipv6_drop_membership-.patch. Your bisect is right, and thanks for chasing it all the way down -- the splat is real and the patch you landed on is the trigger. I've dropped the ipv6 mcast RTNL conversion patches from the 6.12, 6.6 and 5.15 queues. > If I take 6.12.110, apply the current stable-queue (as of commit > 01b20bb84b994fdcda64fd07a66ba84c85d0168f), then revert the > following patches: > > ipv6-mcast-don-t-hold-rtnl-for-ipv6_drop_membership-.patch > ipv6-mcast-don-t-hold-rtnl-for-mcast_-socket-options.patch > ipv6-mcast-use-copy-on-write-rcu-updates-in-ip6_mc_s.patch > > then the resulting kernel no longer shows these warnings at all. The root cause is a prerequisite we never picked up, rather than anything wrong with the patches themselves. Upstream commit e01b193e0b50a ("ipv6: mcast: Use in6_dev_get() in ipv6_dev_mc_dec().") is the commit in that series which deletes the now-stale ASSERT_RTNL() from __ipv6_dev_mc_dec(), and it was never backported to 6.12.y, 6.6.y or 5.15.y. So we took the patches that stop holding RTNL across the setsockopt paths while the assertion they were meant to retire was still sitting there -- hence net/ipv6/mcast.c:1014 firing on every IPV6_DROP_MEMBERSHIP. The queued patches are byte-identical cherry-picks of the upstream commits; this is a series-ordering gap on our side, not a botched backport. 7.2 and 6.18 carry the whole series, including e01b193e0b50a, so they are not affected and keep their copies. One difference from your experiment: I removed four patches rather than the three you reverted. The extra one is 1767bb2d47b7 ("ipv6: mcast: Don't hold RTNL for IPV6_ADD_MEMBERSHIP and MCAST_JOIN_GROUP."), which is a pure refactor of the join path and was only ever queued as a dependency of the others. It is harmless on its own so consistent with you not needing to revert it, but with the rest gone there is no reason to keep it, and dropping it keeps the series intact for a clean requeue. The plan is to requeue the complete ordered set, e01b193e0b50a included, once this RC is out. -- Thanks, Sasha