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BUG: KASAN: out-of-bounds in memcpy_from_iter lib/iov_iter.c:85 [inline]
BUG: KASAN: out-of-bounds in iterate_bvec include/linux/iov_iter.h:123 [inline]
BUG: KASAN: out-of-bounds in iterate_and_advance2 include/linux/iov_iter.h:306 [inline]
BUG: KASAN: out-of-bounds in iterate_and_advance include/linux/iov_iter.h:330 [inline]
BUG: KASAN: out-of-bounds in __copy_from_iter lib/iov_iter.c:261 [inline]
BUG: KASAN: out-of-bounds in copy_folio_from_iter_atomic+0xbbf/0x1a30 lib/iov_iter.c:491
Read of size 4096 at addr ffff888030dce000 by task kworker/u8:6/10245

CPU: 0 UID: 0 PID: 10245 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: loop9 loop_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:4380
 shmem_file_write_iter+0xfb/0x120 mm/shmem.c:3414
 lo_rw_aio+0xc78/0xf30 include/linux/percpu-rwsem.h:-1
 do_req_filebacked drivers/block/loop.c:429 [inline]
 loop_handle_cmd drivers/block/loop.c:1921 [inline]
 loop_process_work+0x638/0x11d0 drivers/block/loop.c:1956
 process_one_work+0x93a/0x12b0 kernel/workqueue.c:3326
 process_scheduled_works kernel/workqueue.c:3409 [inline]
 worker_thread+0xb05/0x10d0 kernel/workqueue.c:3490
 kthread+0x388/0x470 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:2 mapcount:0 mapping:ffff8880237b1760 index:0x21 pfn:0x30dce
memcg:ffff88801ba84180
aops:def_blk_aops ino:700009
flags: 0x90000000000021(locked|lru|node=0|zone=1)
raw: 0090000000000021 ffffea0001990b08 ffffea0001b07388 ffff8880237b1760
raw: 0000000000000021 0000000000000000 00000002ffffffff ffff88801ba84180
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x152c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_HARDWALL), pid 5984, tgid 5984 (udevd), ts 825217619896, free_ts 825195056700
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0x2639/0x26b0 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304
 alloc_pages_mpol+0xce/0x280 mm/mempolicy.c:2490
 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline]
 alloc_pages_noprof+0xd2/0x2f0 mm/mempolicy.c:2581
 folio_alloc_noprof+0x22/0xc0 mm/mempolicy.c:2591
 filemap_alloc_folio_noprof+0x111/0x4d0 mm/filemap.c:1013
 ractl_alloc_folio mm/readahead.c:200 [inline]
 page_cache_ra_unbounded+0x2d6/0x8f0 mm/readahead.c:288
 do_page_cache_ra mm/readahead.c:350 [inline]
 force_page_cache_ra+0x2fe/0x370 mm/readahead.c:380
 filemap_get_pages+0x47a/0x1e30 mm/filemap.c:2704
 filemap_read+0x429/0x11e0 mm/filemap.c:2814
 blkdev_read_iter+0x2f8/0x430 block/fops.c:830
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x59e/0xa90 fs/read_write.c:574
 ksys_read+0x156/0x270 fs/read_write.c:716
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 16321 tgid 16321 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x10de/0x11c0 mm/page_alloc.c:2950
 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:647
 kill_block_super+0x44/0x90 fs/super.c:1665
 deactivate_locked_super+0xbc/0x130 fs/super.c:477
 cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
 exit_to_user_mode_loop+0x1fa/0x730 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888030dcef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888030dcef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888030dcf000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                   ^
 ffff888030dcf080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888030dcf100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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