On Mon, Apr 12, 2021 at 3:07 AM Wang Yugui [off-list ref] wrote:

Hi,

kernel BUG at mm/huge_memory.c:2736(linux 5.10.29) is triggered
by some files write test.

mm/huge_memory.c:
        if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
            pr_alert("total_mapcount: %u, page_count(): %u\n",
                    mapcount, count);
            if (PageTail(page))
                dump_page(head, NULL);
            dump_page(page, "total_mapcount(head) > 0");
L2736:           BUG();
        }

We just can tell the mapcount of the page is not zero from the current
log, it might mean the unmap_page() call is failed. It seems you have
CONFIG_DEBUG_VM enabled, could you please paste more log? There is
"VM_BUG_ON_PAGE(!unmap_success, page)" in unmap_page(). It should be
able to tell us if unmap_page() is failed or not, or something else
happened.

kernel version:5.10.29

kernel BUG at mm/huge_memory.c:2736
invalid opcode: 0000 [#1] SMP NOPTI
CPU:9 pid:351 Comm: kswapd0 Tainted: G S
RIP: 0010:split_huge_page_to_list.cold.86+0x19/8x1b
...
Call Trace:
? shrink_inactive_list+0x241/0x3d0
deferred_split_scan+0x1ca/0x320
do_shrink_slab+0x20f/0x2c0
shrink_node+0x24b/0x6d0
balanced_pgdat+0x2db/0x550
kswaped+0x201/0x390
? finish_wait+0x80/0x80
? balance_pgdat+0x550/0x550
kthread+0x116/0x130
? ktrhead_park+0x80/0x80
ret_from_fork+0x1f/0x30

see OOPS.jpg for more info.

Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2021/04/12