Hello, syzbot found the following issue on: HEAD commit: 73d0e32571a0 Add linux-next specific files for 20220607 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=1433bacff00000 kernel config: https://syzkaller.appspot.com/x/.config?x=448ee2b64e828049 dashboard link: https://syzkaller.appspot.com/bug?extid=d2dd123304b4ae59f1bd compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d2dd123304b4ae59f1bd@xxxxxxxxxxxxxxxxxxxxxxxxx BTRFS error (device loop2): bad tree block start, want 22036480 have 0 ================================================================== BUG: KASAN: use-after-free in copy_page_from_iter_atomic+0xef6/0x1b30 lib/iov_iter.c:969 Read of size 4096 at addr ffff888177101000 by task kworker/u4:30/4131 CPU: 0 PID: 4131 Comm: kworker/u4:30 Not tainted 5.19.0-rc1-next-20220607-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: loop2 loop_workfn Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x495 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 memcpy+0x20/0x60 mm/kasan/shadow.c:65 copy_page_from_iter_atomic+0xef6/0x1b30 lib/iov_iter.c:969 generic_perform_write+0x2b8/0x560 mm/filemap.c:3734 __generic_file_write_iter+0x2aa/0x4d0 mm/filemap.c:3854 generic_file_write_iter+0xd7/0x220 mm/filemap.c:3886 call_write_iter include/linux/fs.h:2059 [inline] do_iter_readv_writev+0x3d1/0x640 fs/read_write.c:742 do_iter_write+0x182/0x700 fs/read_write.c:868 vfs_iter_write+0x70/0xa0 fs/read_write.c:909 lo_write_bvec drivers/block/loop.c:249 [inline] lo_write_simple drivers/block/loop.c:271 [inline] do_req_filebacked drivers/block/loop.c:495 [inline] loop_handle_cmd drivers/block/loop.c:1859 [inline] loop_process_work+0xd83/0x2050 drivers/block/loop.c:1894 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 </TASK> The buggy address belongs to the physical page: page:ffffea0005dc4040 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x177101 flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff) raw: 057ff00000000000 ffffea0005dc4048 ffffea0005dc4048 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner info is not present (never set?) Memory state around the buggy address: ffff888177100f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888177100f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff888177101000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff888177101080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff888177101100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
