Hi, > > kernel: at least 5.10.26/5.10.27/5.10.28 > > > > This problem is triggered by our application, NOT xfstests. > > But our applicaiton have some heavy write load just like xfstest/generic/476. > > Our application use at most 75% of memory, if still not enough, > > it will write out all buffer info to filesystem. > > Do you use cgroups at all? If yes can you describe the workload pattern > a bit. cgroups is enabled defaultly, so cgroups is used. This is the output of systemd-cgls, ''samtools.nipt sort -m 60G" is one of our application. but our application is NOT cgroups-aware, and it NOT call any cgroup interface directly. Control group /: -.slice ├─user.slice │ └─user-0.slice │ ├─session-55.scope │ │ ├─48747 sshd: root [priv] │ │ ├─48788 sshd: root@notty │ │ ├─48795 perl -e @GNU_Parallel=split/_/,"use_IPC::Open3;_use_MIME::Base6... │ │ ├─48943 samtools.nipt sort -m 60G -T /nodetmp//nfs/biowrk/baseline.wgs2... │ │ ├─.... │ └─user@0.service │ └─init.scope │ ├─48775 /usr/lib/systemd/systemd --user │ └─48781 (sd-pam) ├─init.scope │ └─1 /usr/lib/systemd/systemd --switched-root --system --deserialize 18 └─system.slice ├─rngd.service │ └─1577 /sbin/rngd -f --fill-watermark=0 ├─irqbalance.service │ └─1543 /usr/sbin/irqbalance --foreground .... > > This problem is happen in linux kernel 5.10.x, but not happen in linux > > kernel 5.4.x. It have high frequency to repduce too. > > Ah. Can you try the following patch? > https://lore.kernel.org/lkml/20210408035736.883861-4-guro@xxxxxx/ > > Thanks, > Dennis kernel: kernel 5.10.28+this patch result: yet not happen after 4 times test. without this path, the reproduce frequency is >50% And a question about this, > > > > upper caller: > > > > nofs_flag = memalloc_nofs_save(); > > > > ret = btrfs_drew_lock_init(&root->snapshot_lock); > > > > memalloc_nofs_restore(nofs_flag); > > The issue is here. nofs is set which means percpu attempts an atomic > allocation. If it cannot find anything already allocated it isn't happy. > This was done before memalloc_nofs_{save/restore}() were pervasive. > > Percpu should probably try to allocate some pages if possible even if > nofs is set. Should we check and pre-alloc memory inside memalloc_nofs_restore()? another memalloc_nofs_save() may come soon. something like this in memalloc_nofs_save()? if (pcpu_nr_empty_pop_pages[type] < PCPU_EMPTY_POP_PAGES_LOW) pcpu_schedule_balance_work(); by the way, this problem still happen in kernel 5.10.28+this patch. Is this is a PANIC without OOPS? any guide for troubleshooting please. > problem: > OS/VGA console is freezed , and no call trace is outputed. > Just some info is outputed to IPMI/dell iDRAC > 2 | 04/03/2021 | 11:35:01 | OS Critical Stop #0x46 | Run-time critical stop () | Asserted > 3 | Linux kernel panic: Fatal excep > 4 | Linux kernel panic: tion Best Regards Wang Yugui (wangyugui@xxxxxxxxxxxx) 2021/04/08
