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BUG: KASAN: use-after-free in copy_page_from_iter_atomic+0x7d9/0x1070 lib/iov_iter.c:969
Read of size 4096 at addr ffff88807d729000 by task kworker/u4:12/3819

CPU: 1 PID: 3819 Comm: kworker/u4:12 Not tainted 5.19.0-syzkaller-02972-g200e340f2196 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Workqueue: loop0 loop_workfn

Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description+0x65/0x4b0 mm/kasan/report.c:313
 print_report+0xf4/0x210 mm/kasan/report.c:429
 kasan_report+0xfb/0x130 mm/kasan/report.c:491
 kasan_check_range+0x2a7/0x2e0 mm/kasan/generic.c:189
 memcpy+0x25/0x60 mm/kasan/shadow.c:65
 copy_page_from_iter_atomic+0x7d9/0x1070 lib/iov_iter.c:969
 generic_perform_write+0x384/0x610 mm/filemap.c:3752
 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3872
 generic_file_write_iter+0xa7/0x1b0 mm/filemap.c:3904
 do_iter_readv_writev+0x415/0x5a0
 do_iter_write+0x1f1/0x7a0 fs/read_write.c:857
 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+0x14bf/0x2330 drivers/block/loop.c:1894
 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289
 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
 kthread+0x266/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001f5ca40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7d729
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0002207808 ffffea000070a208 0000000000000000
raw: 0000000000000000 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 0x100dc0(GFP_USER|__GFP_ZERO), pid 4893, tgid 4892 (syz-executor.0), ts 1072521745408, free_ts 1072534561600
 prep_new_page mm/page_alloc.c:2457 [inline]
 get_page_from_freelist+0x72b/0x7a0 mm/page_alloc.c:4203
 __alloc_pages+0x259/0x560 mm/page_alloc.c:5431
 lbmLogInit fs/jfs/jfs_logmgr.c:1816 [inline]
 lmLogInit+0x37c/0x1cb0 fs/jfs/jfs_logmgr.c:1270
 open_inline_log fs/jfs/jfs_logmgr.c:1175 [inline]
 lmLogOpen+0x4fd/0x1000 fs/jfs/jfs_logmgr.c:1069
 jfs_mount_rw+0xe3/0x680 fs/jfs/jfs_mount.c:253
 jfs_fill_super+0x675/0xc50 fs/jfs/super.c:565
 mount_bdev+0x26c/0x3a0 fs/super.c:1367
 legacy_get_tree+0xea/0x180 fs/fs_context.c:610
 vfs_get_tree+0x88/0x270 fs/super.c:1497
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1371 [inline]
 free_pcp_prepare+0x812/0x900 mm/page_alloc.c:1421
 free_unref_page_prepare mm/page_alloc.c:3344 [inline]
 free_unref_page+0x7d/0x390 mm/page_alloc.c:3439
 lbmLogShutdown fs/jfs/jfs_logmgr.c:1864 [inline]
 lmLogShutdown+0x4ed/0x960 fs/jfs/jfs_logmgr.c:1684
 lmLogClose+0x291/0x530 fs/jfs/jfs_logmgr.c:1460
 jfs_umount+0x297/0x370 fs/jfs/jfs_umount.c:116
 jfs_put_super+0x86/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x128/0x300 fs/super.c:462
 kill_block_super+0x79/0xd0 fs/super.c:1394
 deactivate_locked_super+0xa7/0xf0 fs/super.c:332
 cleanup_mnt+0x452/0x500 fs/namespace.c:1186
 task_work_run+0x146/0x1c0 kernel/task_work.c:177
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x134/0x160 kernel/entry/common.c:169
 exit_to_user_mode_prepare+0xad/0x110 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x2e/0x60 kernel/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff88807d728f00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
 ffff88807d728f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88807d729000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88807d729080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807d729100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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