==================================================================
BUG: KASAN: use-after-free in memcpy_from_iter lib/iov_iter.c:85 [inline]
BUG: KASAN: use-after-free in iterate_bvec include/linux/iov_iter.h:123 [inline]
BUG: KASAN: use-after-free in iterate_and_advance2 include/linux/iov_iter.h:306 [inline]
BUG: KASAN: use-after-free in iterate_and_advance include/linux/iov_iter.h:330 [inline]
BUG: KASAN: use-after-free in __copy_from_iter lib/iov_iter.c:261 [inline]
BUG: KASAN: use-after-free in copy_folio_from_iter_atomic+0xbbf/0x1a30 lib/iov_iter.c:491
Read of size 4096 at addr ffff8880351c3000 by task kworker/u8:7/161

CPU: 1 UID: 0 PID: 161 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: loop0 loop_rootcg_workfn
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x264/0x2c0 mm/kasan/generic.c:200
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 memcpy_from_iter lib/iov_iter.c:85 [inline]
 iterate_bvec include/linux/iov_iter.h:123 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:306 [inline]
 iterate_and_advance include/linux/iov_iter.h:330 [inline]
 __copy_from_iter lib/iov_iter.c:261 [inline]
 copy_folio_from_iter_atomic+0xbbf/0x1a30 lib/iov_iter.c:491
 generic_perform_write+0x5a8/0x8b0 mm/filemap.c:4392
 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:3443
 lo_rw_aio+0xc78/0xf30 include/linux/percpu-rwsem.h:-1
 do_req_filebacked drivers/block/loop.c:430 [inline]
 loop_handle_cmd drivers/block/loop.c:1949 [inline]
 loop_process_work+0x638/0x11d0 drivers/block/loop.c:1984
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x34 pfn:0x351c3
flags: 0x80000000000000(node=0|zone=1)
raw: 0080000000000000 ffffea0000fd8a48 ffffea0000abadc8 0000000000000000
raw: 0000000000000034 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xdc0(GFP_KERNEL|__GFP_ZERO), pid 5742, tgid 5742 (syz-executor393), ts 132973177254
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436
 alloc_pages_mpol+0xd4/0x280 mm/mempolicy.c:2486
 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
 alloc_pages_noprof+0xd2/0x2f0 mm/mempolicy.c:2577
 lbmLogInit fs/jfs/jfs_logmgr.c:1813 [inline]
 lmLogInit+0x357/0x1a20 fs/jfs/jfs_logmgr.c:1267
 open_inline_log fs/jfs/jfs_logmgr.c:1173 [inline]
 lmLogOpen+0x4e3/0xf90 fs/jfs/jfs_logmgr.c:1067
 jfs_mount_rw+0xf3/0x670 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x769/0xda0 fs/jfs/super.c:533
 get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1872
 vfs_get_tree+0x92/0x2a0 fs/super.c:1932
 fc_mount fs/namespace.c:1282 [inline]
 do_new_mount_fc fs/namespace.c:3898 [inline]
 do_new_mount+0x325/0xb00 fs/namespace.c:3974
 do_mount fs/namespace.c:4338 [inline]
 __do_sys_mount fs/namespace.c:4556 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4533
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5595 tgid 5595 ts 133041313171 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 __free_frozen_pages+0xf8e/0x1070 mm/page_alloc.c:2962
 lbmLogShutdown fs/jfs/jfs_logmgr.c:1861 [inline]
 lmLogShutdown+0x44e/0x850 fs/jfs/jfs_logmgr.c:1681
 lmLogClose+0x28c/0x530 fs/jfs/jfs_logmgr.c:1457
 jfs_umount+0x2da/0x3b0 fs/jfs/jfs_umount.c:124
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:751
 kill_block_super+0x44/0xa0 fs/super.c:1903
 deactivate_locked_super+0xbe/0x110 fs/super.c:586
 cleanup_mnt+0x204/0x2a0 fs/namespace.c:1396
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 ptrace_notify+0x27c/0x2b0 kernel/signal.c:2597
 ptrace_report_syscall include/linux/ptrace.h:416 [inline]
 ptrace_report_syscall_exit+0x2d/0x50 include/linux/ptrace.h:477
 arch_ptrace_report_syscall_exit include/linux/entry-common.h:240 [inline]
 syscall_exit_work include/linux/entry-common.h:273 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:304 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:341 [inline]
 do_syscall_64+0x4a0/0x520 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880351c2f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880351c2f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880351c3000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8880351c3080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880351c3100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================