On Fri, Sep 25, 2020 at 9:19 AM Ming Lei <ming.lei@xxxxxxxxxx> wrote: > > On Fri, Sep 25, 2020 at 03:31:45PM +0800, Ming Lei wrote: > > On Thu, Sep 24, 2020 at 09:13:11PM -0400, Theodore Y. Ts'o wrote: > > > On Thu, Sep 24, 2020 at 10:33:45AM -0400, Theodore Y. Ts'o wrote: > > > > HOWEVER, thanks to a hint from a colleague at $WORK, and realizing > > > > that one of the stack traces had virtio balloon in the trace, I > > > > realized that when I switched the GCE VM type from e1-standard-2 to > > > > n1-standard-2 (where e1 VM's are cheaper because they use > > > > virtio-balloon to better manage host OS memory utilization), problem > > > > has become, much, *much* rarer (and possibly has gone away, although > > > > I'm going to want to run a lot more tests before I say that > > > > conclusively) on my test setup. At the very least, using an n1 VM > > > > (which doesn't have virtio-balloon enabled in the hypervisor) is > > > > enough to unblock ext4 development. > > > > > > .... and I spoke too soon. A number of runs using -rc6 are now > > > failing even with the n1-standard-2 VM, so virtio-ballon may not be an > > > indicator. > > > > > > This is why debugging this is frustrating; it is very much a heisenbug > > > --- although 5.8 seems to work completely reliably, as does commits > > > before 37f4a24c2469. Anything after that point will show random > > > failures. :-( > > > > It does not make sense to mention 37f4a24c2469, which is reverted in > > 4e2f62e566b5. Later the patch in 37f4a24c2469 is fixed and re-commited > > as 568f27006577. > > > > However, I can _not_ reproduce the issue by running the same test on > > kernel built from 568f27006577 directly. > > > > Also you have confirmed that the issue can't be fixed after reverting > > 568f27006577 against v5.9-rc4. > > > > Looks the real issue(slab list corruption) should be introduced between > > 568f27006577 and v5.9-rc4. > > git bisect shows the first bad commit: > > [10befea91b61c4e2c2d1df06a2e978d182fcf792] mm: memcg/slab: use a single set of > kmem_caches for all allocations > > And I have double checked that the above commit is really the first bad > commit for the list corruption issue of 'list_del corruption, ffffe1c241b00408->next > is LIST_POISON1 (dead000000000100)', see the detailed stack trace and > kernel oops log in the following link: > > https://lore.kernel.org/lkml/20200916202026.GC38283@xxxxxxx/ The failure signature is similar to https://lore.kernel.org/lkml/20200901075321.GL4299@shao2-debian/ > > And the kernel config is the one(without KASAN) used by Theodore in GCE VM, see > the following link: > > https://lore.kernel.org/lkml/20200917143012.GF38283@xxxxxxx/ > > The reproducer is xfstests generic/038. In my setting, test device is virtio-scsi, and > scratch device is virtio-blk. > > > [1] git bisect log: > > git bisect start > # good: [568f2700657794b8258e72983ba508793a658942] blk-mq: centralise related handling into blk_mq_get_driver_tag > git bisect good 568f2700657794b8258e72983ba508793a658942 > # bad: [f4d51dffc6c01a9e94650d95ce0104964f8ae822] Linux 5.9-rc4 > git bisect bad f4d51dffc6c01a9e94650d95ce0104964f8ae822 > # good: [8186749621ed6b8fc42644c399e8c755a2b6f630] Merge tag 'drm-next-2020-08-06' of git://anongit.freedesktop.org/drm/drm > git bisect good 8186749621ed6b8fc42644c399e8c755a2b6f630 > # good: [60e76bb8a4e4c5398ea9053535e1fd0c9d6bb06e] Merge tag 'm68knommu-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu > git bisect good 60e76bb8a4e4c5398ea9053535e1fd0c9d6bb06e > # bad: [57b077939287835b9396a1c3b40d35609cf2fcb8] Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost > git bisect bad 57b077939287835b9396a1c3b40d35609cf2fcb8 > # bad: [0f43283be7fec4a76cd4ed50dc37db30719bde05] Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs > git bisect bad 0f43283be7fec4a76cd4ed50dc37db30719bde05 > # good: [5631c5e0eb9035d92ceb20fcd9cdb7779a3f5cc7] Merge tag 'xfs-5.9-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux > git bisect good 5631c5e0eb9035d92ceb20fcd9cdb7779a3f5cc7 > # good: [e3083c3f369700cd1eec3de93b8d8ec0918ff778] media: cafe-driver: use generic power management > git bisect good e3083c3f369700cd1eec3de93b8d8ec0918ff778 > # bad: [42742d9bde2a8e11ec932cb5821f720a40a7c2a9] mm: thp: replace HTTP links with HTTPS ones > git bisect bad 42742d9bde2a8e11ec932cb5821f720a40a7c2a9 > # bad: [10befea91b61c4e2c2d1df06a2e978d182fcf792] mm: memcg/slab: use a single set of kmem_caches for all allocations > git bisect bad 10befea91b61c4e2c2d1df06a2e978d182fcf792 > # good: [cfbe1636c3585c1e032bfac512fb8be903fbc913] mm, kcsan: instrument SLAB/SLUB free with "ASSERT_EXCLUSIVE_ACCESS" > git bisect good cfbe1636c3585c1e032bfac512fb8be903fbc913 > # good: [0f190a7ab78878f9e6c6930fc0f5f92c1250b57d] mm/page_io.c: use blk_io_schedule() for avoiding task hung in sync io > git bisect good 0f190a7ab78878f9e6c6930fc0f5f92c1250b57d > # good: [286e04b8ed7a04279ae277f0f024430246ea5eec] mm: memcg/slab: allocate obj_cgroups for non-root slab pages > git bisect good 286e04b8ed7a04279ae277f0f024430246ea5eec > # good: [9855609bde03e2472b99a95e869d29ee1e78a751] mm: memcg/slab: use a single set of kmem_caches for all accounted allocations > git bisect good 9855609bde03e2472b99a95e869d29ee1e78a751 > # good: [272911a4ad18c48f8bc449a5db945a54987dd687] mm: memcg/slab: remove memcg_kmem_get_cache() > git bisect good 272911a4ad18c48f8bc449a5db945a54987dd687 > # good: [15999eef7f25e2ea6a1c33f026166f472c5714e9] mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo() > git bisect good 15999eef7f25e2ea6a1c33f026166f472c5714e9 > # first bad commit: [10befea91b61c4e2c2d1df06a2e978d182fcf792] mm: memcg/slab: use a single set of kmem_caches for all allocations > > > > Thanks, > Ming >
