=====================================================
BUG: KMSAN: uninit-value in is_folio_zero_filled mm/page_io.c:188 [inline]
BUG: KMSAN: uninit-value in swap_writepage+0x547/0x1950 mm/page_io.c:266
 is_folio_zero_filled mm/page_io.c:188 [inline]
 swap_writepage+0x547/0x1950 mm/page_io.c:266
 shmem_writepage+0x2348/0x2590 mm/shmem.c:1647
 pageout mm/vmscan.c:696 [inline]
 shrink_folio_list+0x5dd2/0x8220 mm/vmscan.c:1402
 evict_folios+0x94ed/0xb9c0 mm/vmscan.c:4660
 try_to_shrink_lruvec+0xc58/0x1080 mm/vmscan.c:4821
 lru_gen_shrink_lruvec mm/vmscan.c:4970 [inline]
 shrink_lruvec+0x49a/0x47d0 mm/vmscan.c:5715
 shrink_node_memcgs mm/vmscan.c:5951 [inline]
 shrink_node+0x105e/0x51c0 mm/vmscan.c:5992
 shrink_zones mm/vmscan.c:6237 [inline]
 do_try_to_free_pages+0x820/0x2550 mm/vmscan.c:6299
 try_to_free_mem_cgroup_pages+0x3fa/0xa60 mm/vmscan.c:6631
 try_charge_memcg+0x71a/0x1780 mm/memcontrol.c:2264
 obj_cgroup_charge_pages+0x2cb/0x640 mm/memcontrol.c:2645
 __memcg_kmem_charge_page+0x151/0x520 mm/memcontrol.c:2672
 __alloc_frozen_pages_noprof+0x93d/0xe00 mm/page_alloc.c:4757
 alloc_pages_mpol+0x4cd/0x890 mm/mempolicy.c:2270
 alloc_frozen_pages_noprof mm/mempolicy.c:2341 [inline]
 alloc_pages_noprof+0x1b5/0x250 mm/mempolicy.c:2361
 io_mem_alloc_compound io_uring/memmap.c:29 [inline]
 io_region_allocate_pages+0x168/0x8b0 io_uring/memmap.c:167
 io_create_region+0x6eb/0x810 io_uring/memmap.c:223
 io_allocate_scq_urings+0x774/0xa50 io_uring/io_uring.c:3508
 io_uring_create+0xabc/0x1440 io_uring/io_uring.c:3703
 io_uring_setup io_uring/io_uring.c:3793 [inline]
 __do_sys_io_uring_setup io_uring/io_uring.c:3820 [inline]
 __se_sys_io_uring_setup+0x476/0x4d0 io_uring/io_uring.c:3814
 __x64_sys_io_uring_setup+0x6c/0xa0 io_uring/io_uring.c:3814
 x64_sys_call+0x2e82/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:426
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 memcpy_from_iter lib/iov_iter.c:73 [inline]
 iterate_bvec include/linux/iov_iter.h:123 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 __copy_from_iter lib/iov_iter.c:249 [inline]
 copy_page_from_iter_atomic+0x1314/0x3450 lib/iov_iter.c:483
 copy_folio_from_iter_atomic include/linux/uio.h:210 [inline]
 generic_perform_write+0x83f/0x1060 mm/filemap.c:4120
 shmem_file_write_iter+0x2ba/0x2f0 mm/shmem.c:3477
 do_iter_readv_writev+0x93a/0xbc0
 vfs_iter_write+0x44d/0xd60 fs/read_write.c:974
 lo_write_bvec drivers/block/loop.c:245 [inline]
 lo_write_simple drivers/block/loop.c:266 [inline]
 do_req_filebacked drivers/block/loop.c:520 [inline]
 loop_handle_cmd drivers/block/loop.c:1929 [inline]
 loop_process_work+0x15fb/0x3760 drivers/block/loop.c:1964
 loop_workfn+0x48/0x60 drivers/block/loop.c:1988
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xc1a/0x1e80 kernel/workqueue.c:3319
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3400
 kthread+0x6b9/0xef0 kernel/kthread.c:464
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 __alloc_frozen_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4763
 __alloc_pages_noprof mm/page_alloc.c:4774 [inline]
 alloc_pages_bulk_noprof+0x1227/0x1a60 mm/page_alloc.c:4694
 btrfs_alloc_page_array fs/btrfs/extent_io.c:631 [inline]
 alloc_eb_folio_array+0x199/0x750 fs/btrfs/extent_io.c:655
 alloc_extent_buffer+0x76a/0x36f0 fs/btrfs/extent_io.c:3103
 btrfs_find_create_tree_block+0x46/0x60 fs/btrfs/disk-io.c:614
 btrfs_init_new_buffer fs/btrfs/extent-tree.c:5017 [inline]
 btrfs_alloc_tree_block+0x415/0x19c0 fs/btrfs/extent-tree.c:5130
 btrfs_alloc_log_tree_node fs/btrfs/disk-io.c:950 [inline]
 btrfs_add_log_tree+0x1b7/0x7a0 fs/btrfs/disk-io.c:998
 start_log_trans fs/btrfs/tree-log.c:227 [inline]
 btrfs_log_inode_parent+0xa87/0x1c30 fs/btrfs/tree-log.c:7097
 btrfs_log_dentry_safe+0x9a/0x100 fs/btrfs/tree-log.c:7202
 btrfs_sync_file+0x1676/0x2180 fs/btrfs/file.c:1654
 vfs_fsync_range+0x1f9/0x260 fs/sync.c:187
 generic_write_sync include/linux/fs.h:2970 [inline]
 btrfs_do_write_iter+0xab2/0xc90 fs/btrfs/file.c:1391
 btrfs_file_write_iter+0x38/0x50 fs/btrfs/file.c:1401
 do_iter_readv_writev+0x93a/0xbc0
 vfs_writev+0x56a/0x14e0 fs/read_write.c:1050
 do_pwritev fs/read_write.c:1146 [inline]
 __do_sys_pwritev2 fs/read_write.c:1204 [inline]
 __se_sys_pwritev2+0x262/0x460 fs/read_write.c:1195
 __x64_sys_pwritev2+0x11f/0x1a0 fs/read_write.c:1195
 x64_sys_call+0x368c/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:329
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 8112 Comm: syz.0.635 Not tainted 6.14.0-rc7-syzkaller-00074-ga7f2e10ecd8f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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