BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u4:1/21 caller is ext4_mb_new_blocks+0xa4d/0x3b70 fs/ext4/mballoc.c:4711 CPU: 1 PID: 21 Comm: kworker/u4:1 Not tainted 5.8.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 check_preemption_disabled+0x20d/0x220 lib/smp_processor_id.c:48 ext4_mb_new_blocks+0xa4d/0x3b70 fs/ext4/mballoc.c:4711 ext4_ext_map_blocks+0x201b/0x33e0 fs/ext4/extents.c:4244 ext4_map_blocks+0x4cb/0x1640 fs/ext4/inode.c:626 mpage_map_one_extent fs/ext4/inode.c:2377 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2430 [inline] ext4_writepages+0x1a7b/0x33c0 fs/ext4/inode.c:2782 do_writepages+0xfa/0x2a0 mm/page-writeback.c:2354 __writeback_single_inode+0x12a/0x13d0 fs/fs-writeback.c:1452 writeback_sb_inodes+0x515/0xdc0 fs/fs-writeback.c:1716 __writeback_inodes_wb+0xc3/0x250 fs/fs-writeback.c:1785 wb_writeback+0x8db/0xd50 fs/fs-writeback.c:1894 wb_check_old_data_flush fs/fs-writeback.c:1996 [inline] wb_do_writeback fs/fs-writeback.c:2049 [inline] wb_workfn+0xab3/0x1090 fs/fs-writeback.c:2078 process_one_work+0x965/0x1690 kernel/workqueue.c:2269 worker_thread+0x96/0xe10 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293