Message-ID: <CABXGCsNi8Tiv5zUPNXr6UJw6qV1VdaBEfGqEAMkkXE3QPvZuAQ@mail.gmail.com>
Date:   Fri, 1 Sep 2023 03:45:28 +0500
From:   Mikhail Gavrilov <mikhail.v.gavrilov@...il.com>
To:     Hugh Dickins <hughd@...gle.com>
Cc:     Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        Linux Memory Management List <linux-mm@...ck.org>
Subject: 6.6/regression/bisected - after commit a349d72fd9efc87c8fd1d16d3164752d84a7275b
 system stopped booting

Hi,
next release cycle, and another regression.
Yesterday after another kernel update in Fedora Rawhide system stopped booting.
Today thanks to git bisect, I found out that this is a commit:

❯ git bisect bad
a349d72fd9efc87c8fd1d16d3164752d84a7275b is the first bad commit
commit a349d72fd9efc87c8fd1d16d3164752d84a7275b
Author: Hugh Dickins <hughd@...gle.com>
Date:   Tue Jul 11 21:30:40 2023 -0700

    mm/pgtable: add rcu_read_lock() and rcu_read_unlock()s

    Patch series "mm: free retracted page table by RCU", v3.

    Some mmap_lock avoidance i.e.  latency reduction.  Initially just for the
    case of collapsing shmem or file pages to THPs: the usefulness of
    MADV_COLLAPSE on shmem is being limited by that mmap_write_lock it
    currently requires.

    Likely to be relied upon later in other contexts e.g.  freeing of empty
    page tables (but that's not work I'm doing).  mmap_write_lock avoidance
    when collapsing to anon THPs?  Perhaps, but again that's not work I've
    done: a quick attempt was not as easy as the shmem/file case.

    These changes (though of course not these exact patches) have been in
    Google's data centre kernel for three years now: we do rely upon them.


    This patch (of 13):

    Before putting them to use (several commits later), add rcu_read_lock() to
    pte_offset_map(), and rcu_read_unlock() to pte_unmap().  Make this a
    separate commit, since it risks exposing imbalances: prior commits have
    fixed all the known imbalances, but we may find some have been missed.

    Link: https://lkml.kernel.org/r/7cd843a9-aa80-14f-5eb2-33427363c20@google.com
    Link: https://lkml.kernel.org/r/d3b01da5-2a6-833c-6681-67a3e024a16f@google.com
    Signed-off-by: Hugh Dickins <hughd@...gle.com>
    Cc: Alexander Gordeev <agordeev@...ux.ibm.com>
    Cc: Alistair Popple <apopple@...dia.com>
    Cc: Aneesh Kumar K.V <aneesh.kumar@...ux.ibm.com>
    Cc: Anshuman Khandual <anshuman.khandual@....com>
    Cc: Axel Rasmussen <axelrasmussen@...gle.com>
    Cc: Christian Borntraeger <borntraeger@...ux.ibm.com>
    Cc: Christophe Leroy <christophe.leroy@...roup.eu>
    Cc: Christoph Hellwig <hch@...radead.org>
    Cc: Claudio Imbrenda <imbrenda@...ux.ibm.com>
    Cc: David Hildenbrand <david@...hat.com>
    Cc: "David S. Miller" <davem@...emloft.net>
    Cc: Gerald Schaefer <gerald.schaefer@...ux.ibm.com>
    Cc: Heiko Carstens <hca@...ux.ibm.com>
    Cc: Huang, Ying <ying.huang@...el.com>
    Cc: Ira Weiny <ira.weiny@...el.com>
    Cc: Jann Horn <jannh@...gle.com>
    Cc: Jason Gunthorpe <jgg@...pe.ca>
    Cc: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
    Cc: Lorenzo Stoakes <lstoakes@...il.com>
    Cc: Matthew Wilcox (Oracle) <willy@...radead.org>
    Cc: Mel Gorman <mgorman@...hsingularity.net>
    Cc: Miaohe Lin <linmiaohe@...wei.com>
    Cc: Michael Ellerman <mpe@...erman.id.au>
    Cc: Mike Kravetz <mike.kravetz@...cle.com>
    Cc: Mike Rapoport (IBM) <rppt@...nel.org>
    Cc: Minchan Kim <minchan@...nel.org>
    Cc: Naoya Horiguchi <naoya.horiguchi@....com>
    Cc: Pavel Tatashin <pasha.tatashin@...een.com>
    Cc: Peter Xu <peterx@...hat.com>
    Cc: Peter Zijlstra <peterz@...radead.org>
    Cc: Qi Zheng <zhengqi.arch@...edance.com>
    Cc: Ralph Campbell <rcampbell@...dia.com>
    Cc: Russell King <linux@...linux.org.uk>
    Cc: SeongJae Park <sj@...nel.org>
    Cc: Song Liu <song@...nel.org>
    Cc: Steven Price <steven.price@....com>
    Cc: Suren Baghdasaryan <surenb@...gle.com>
    Cc: Thomas Hellström <thomas.hellstrom@...ux.intel.com>
    Cc: Vasily Gorbik <gor@...ux.ibm.com>
    Cc: Vishal Moola (Oracle) <vishal.moola@...il.com>
    Cc: Vlastimil Babka <vbabka@...e.cz>
    Cc: Will Deacon <will@...nel.org>
    Cc: Yang Shi <shy828301@...il.com>
    Cc: Yu Zhao <yuzhao@...gle.com>
    Cc: Zack Rusin <zackr@...are.com>
    Cc: Zi Yan <ziy@...dia.com>
    Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>

 include/linux/pgtable.h | 4 ++--
 mm/pgtable-generic.c    | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

It looks like the hang happens so early that when booting into a
working kernel and running "journalctl -b -1" I see in the console the
log of the previous kernel which was booted before the problematic
kernel.
Therefore, I apologize that I can't provide the kernel logs.
I can provides only photos when backtrace appears on my monitor:
Here we waiting: https://ibb.co/5xmm0BH
And then I see backtrace: https://ibb.co/TLLGFNP

Unfortunately I can't revert commit
a349d72fd9efc87c8fd1d16d3164752d84a7275b for testing more fresh builds
because of conflicts.

My hardware: https://linux-hardware.org/?probe=dd5735f315
I also attached kernel build config and full bisect log.

-- 
Best Regards,
Mike Gavrilov.

Download attachment ".config.zip" of type "application/zip" (64077 bytes)

Download attachment "git-bisect-system-not-boot.zip" of type "application/zip" (1875 bytes)

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