On Mon, Apr 24, 2023 at 11:16 PM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote: > > Hi, > > 在 2023/04/25 8:23, Song Liu 写道: > > On Thu, Apr 20, 2023 at 4:31 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote: > >> > >> From: Yu Kuai <yukuai3@xxxxxxxxxx> > >> > >> Currently, there is no limit for raid1/raid10 plugged bio. While flushing > >> writes, raid1 has cond_resched() while raid10 doesn't, and too many > >> writes can cause soft lockup. > >> > >> Follow up soft lockup can be triggered easily with writeback test for > >> raid10 with ramdisks: > >> > >> watchdog: BUG: soft lockup - CPU#10 stuck for 27s! [md0_raid10:1293] > >> Call Trace: > >> <TASK> > >> call_rcu+0x16/0x20 > >> put_object+0x41/0x80 > >> __delete_object+0x50/0x90 > >> delete_object_full+0x2b/0x40 > >> kmemleak_free+0x46/0xa0 > >> slab_free_freelist_hook.constprop.0+0xed/0x1a0 > >> kmem_cache_free+0xfd/0x300 > >> mempool_free_slab+0x1f/0x30 > >> mempool_free+0x3a/0x100 > >> bio_free+0x59/0x80 > >> bio_put+0xcf/0x2c0 > >> free_r10bio+0xbf/0xf0 > >> raid_end_bio_io+0x78/0xb0 > >> one_write_done+0x8a/0xa0 > >> raid10_end_write_request+0x1b4/0x430 > >> bio_endio+0x175/0x320 > >> brd_submit_bio+0x3b9/0x9b7 [brd] > >> __submit_bio+0x69/0xe0 > >> submit_bio_noacct_nocheck+0x1e6/0x5a0 > >> submit_bio_noacct+0x38c/0x7e0 > >> flush_pending_writes+0xf0/0x240 > >> raid10d+0xac/0x1ed0 > > > > Is it possible to trigger this with a mdadm test? > > > > The test I mentioned in patch 8 can trigger this problem reliablity, so > I this add a new test can achieve this. To be clear, by "mdadm test" I mean the tests included in mdadm: https://git.kernel.org/pub/scm/utils/mdadm/mdadm.git/tree/tests Could you please try to add a test? If it works, we should add it to mdadm. Thanks, Song
