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b=QBRYFQz5RTCmVbvuVbgrR2TdBhZPz21zHiCpfBbQ/2P+18ztTuSIwWEN7fYxYK7Go 2r0/1F5w1jdvDFBaJfn2Idama23UR+CceHtAKtV4lhy2qc6XE6yaDx4s223npvokb3 ceYc6aYzP8nV1pVgNqT+RCPhpX9Z3jYTUOj/S9ee2rlIBT1MlWAQH2D0RQhTNzhU5L nE+30paIAZr30qyAzEFaiIIsVNhvuC/GjPL9diq/bHKKumMlblrLS2+yfe8ve6qbl1 jTbHjnWViWqsQJGDf1hyuA99Ky2aDigW+SDvSSihAfC849JCTGlMaRhiyT7rgSuObU q+vmqhOBgSofA== Date: Mon, 19 Oct 2026 17:38:37 +0100 From: "Lorenzo Stoakes (ARM)" To: Andrew Morton Cc: Nikola Ciprich , Sean Christopherson , Borislav Petkov , David Laight , Rik van Riel , linux-mm@kvack.org, linux-kernel@vger.kernel.org, david@kernel.org, Mike Rapoport , Dave Hansen , Pedro Falcato , Kiryl Shutsemau , luizcap@redhat.com, pbonzini@redhat.com, Tal Zussman , Matt Fleming , Yosry Ahmed Subject: Re: hunting memory corruption bug in 6.18.x Message-ID: References: <20261015172820.7961d2c0def74d41cc6c4b0c@linux-foundation.org> <20261016031242.GDatGWKo98YSOhEOOn@fat_crate.local> <20261015211832.45d87fab15bb3e0bbc2f47cb@linux-foundation.org> <20261016054954.GEatG7AgMNFRkiTo1H@fat_crate.local> <20261018201538.d0957878f378a9821852836f@linux-foundation.org> <20261019083529.a81910ac0976c1a5687d4c6a@linux-foundation.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20261019083529.a81910ac0976c1a5687d4c6a@linux-foundation.org> X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 0E773140007 X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,RCVD_IN_DNSWL_BLOCKED, RCVD_IN_ZEN_BLOCKED_OPENDNS,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Stat-Signature: 6u1cyhumh5yo3bjkmybimsrmwjk6qdc9 X-HE-Tag: 1792427924-944938 X-HE-Meta: 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 /RtdqzE2 fiO2y2TWwrrH4n9B5i5b47yTaGDKvgOC07OzxaTsxzee//O0oiQpvRU723ZnlMdBun8ZP9Ew2GX5O5gu64y8UcFDnK2UoCKzFHUz2IZgv1p2a2/tiv/V5q3HbeLiUtGz+M7ufEJa6zYw09ou5t9fwQqJU7Y6ZcR9Q5igGPtnTRL2nFdYvIdUV7Mnq8BbKOtn/udluK9KXT24lfJ9m8bAITuR70SatDDdQAlcXzV2xhAV+HChezpuDZfTn9T3ztk5eu6YB43JA9wP4z8ZukFKFf0Vza+uwQVK9Y6EIcQp15cyh/ow4Rr0ZUyKNOkENRTfuy8c1pKXGrNSARBBujdIoKR7MTxHCgu1mrC+j Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Mon, Oct 19, 2026 at 08:35:29AM -0700, Andrew Morton wrote: > On Mon, 19 Oct 2026 17:22:37 +0200 Nikola Ciprich wrote: > > > > > > > Sure! And I have more good news: after applying 55780d8a1dcc > > > to 6.18.56, I was able to perform more than 30 migrations without > > > a glitch. After booting back into 6.18.56 without it, both VMs > > > crashed within 2-3 migrations. Furthermore, some memory apparently > > > got corrupted on one of the hosts, since various commands started > > > crashing too: > > > > > > [ 303.466091] traps: systemd-logind[3085] trap invalid opcode ip:7f7b5667e616 sp:7ffe1afdec38 error:0 in libsystemd-shared-252.so[7e616,7f7b5666d000+22e000] > > > [ 303.493810] traps: systemd-coredum[11269] trap invalid opcode ip:7fc6bf67f614 sp:7ffc075da958 error:0 in libsystemd-shared-252.so[7f614,7fc6bf66d000+22e000] > > > [ 377.528955] traps: systemd[5607] trap invalid opcode ip:7f791447e616 sp:7ffe83e61cf8 error:0 in libsystemd-shared-252.so[7e616,7f791446d000+22e000] > > > [ 377.556993] traps: systemd-coredum[12080] trap invalid opcode ip:7f97ce07f614 sp:7ffe28b56a88 error:0 in libsystemd-shared-252.so[7f614,7f97ce06d000+22e000] > > > [ 3746.173043] traps: hostnamectl[45846] trap invalid opcode ip:7fe00cc7f614 sp:7fff89916e48 error:0 in libsystemd-shared-252.so[7f614,7fe00cc6d000+22e000] > > > [ 3746.202305] traps: systemd-coredum[45847] trap invalid opcode ip:7f7fe9e7f614 sp:7ffea227cfa8 error:0 in libsystemd-shared-252.so[7f614,7f7fe9e6d000+22e000] > > > [ 3750.581940] traps: systemctl[45903] trap invalid opcode ip:7fbb8967f614 sp:7fff733e5748 error:0 in libsystemd-shared-252.so[7f614,7fbb8966d000+22e000] > > > [ 3750.612651] traps: systemd-coredum[45904] trap invalid opcode ip:7f90d347f614 sp:7ffdc7f55148 error:0 in libsystemd-shared-252.so[7f614,7f90d346d000+22e000] > > > > > > I'm not sure if this is of any use, but I collected a vmcore of > > > this state by intentionally crashing the host via /proc/sysrq-trigger. > > > > > > Anyway, I'll give 55780d8a1dcc some more migration rounds, but it looks > > > promising. > > > > 500+ migrations back and forth, no issues. I consider this solved and am rolling > > out the patched kernel; I’ll report if anything new turns up. > > Great, thanks. > > oops, we haven't been cc'ing Yosry. > > > Definitely a -stable candidate. Andrew, will you send it to Greg, or shall I? > > I volunteer Yosry or Sean ;) > > I think 55780d8a1dcc should be repackaged before sending over to the > -stable people. Its changelog is very wrong: "The bug is benign > though". Update the changelog to explain that the bug is in fact evil. > Otherwise -stable and further downstream won't understand why we sent > it to them and won't understand the impact. > > And that repackaging would be an opportunity to add > Reported-by:/Closes:/Tested-by: you, which is the least we can do to > thank you for all this diligent work! > Very happy to see this tracked down :) thanks to everybody else who got stuck in after me! -- Cheers, Lorenzo