BUG: Bad page state in process kworker/u4:1 pfn:1f9a6b page:ffffea0007e69ac0 refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881f9a6bb98 flags: 0x57ffe0000000000() raw: 057ffe0000000000 dead000000000100 dead000000000122 0000000000000000 raw: ffff8881f9a6bb98 ffff8881f9a6b040 00000000ffffffff ffff8881fae55b01 page dumped because: page still charged to cgroup page->mem_cgroup:ffff8881fae55b01 Modules linked in: CPU: 1 PID: 22199 Comm: kworker/u4:1 Not tainted 5.8.0-rc2-next-20200626-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 bad_page.cold+0x9c/0xbd mm/page_alloc.c:638 check_free_page_bad mm/page_alloc.c:1093 [inline] check_free_page mm/page_alloc.c:1103 [inline] free_pages_prepare mm/page_alloc.c:1204 [inline] free_pcp_prepare+0x2f9/0x390 mm/page_alloc.c:1245 free_unref_page_prepare mm/page_alloc.c:3095 [inline] free_unref_page+0x12/0x2d0 mm/page_alloc.c:3144 slab_destroy mm/slab.c:1615 [inline] slabs_destroy+0x89/0xc0 mm/slab.c:1631 __cache_free_alien mm/slab.c:778 [inline] cache_free_alien mm/slab.c:794 [inline] ___cache_free+0x39a/0x750 mm/slab.c:3442 qlink_free mm/kasan/quarantine.c:148 [inline] qlist_free_all+0x79/0x140 mm/kasan/quarantine.c:167 quarantine_reduce+0x17e/0x200 mm/kasan/quarantine.c:260 __kasan_kmalloc.constprop.0+0x9e/0xd0 mm/kasan/common.c:475 slab_post_alloc_hook mm/slab.h:535 [inline] slab_alloc mm/slab.c:3306 [inline] __do_kmalloc mm/slab.c:3647 [inline] __kmalloc+0x174/0x4d0 mm/slab.c:3658 kmalloc_array+0x42/0x70 include/linux/slab.h:594 kcalloc include/linux/slab.h:605 [inline] ext4_find_extent+0x984/0xce0 fs/ext4/extents.c:869 ext4_ext_map_blocks+0x1e2/0x61b0 fs/ext4/extents.c:4059 ext4_map_blocks+0x7b8/0x1650 fs/ext4/inode.c:626 ext4_convert_unwritten_extents+0x1c6/0x570 fs/ext4/extents.c:4755 ext4_convert_unwritten_io_end_vec+0x122/0x270 fs/ext4/extents.c:4794 ext4_end_io_end fs/ext4/page-io.c:187 [inline] ext4_do_flush_completed_IO fs/ext4/page-io.c:260 [inline] ext4_end_io_rsv_work+0x2b3/0x640 fs/ext4/page-io.c:274 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294