=====================================================
BUG: KMSAN: kernel-infoleak-after-free in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak-after-free in copy_to_user_iter lib/iov_iter.c:24 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_ubuf include/linux/iov_iter.h:30 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KMSAN: kernel-infoleak-after-free in _copy_to_iter+0xf0e/0x32f0 lib/iov_iter.c:185
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 copy_to_user_iter lib/iov_iter.c:24 [inline]
 iterate_ubuf include/linux/iov_iter.h:30 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 _copy_to_iter+0xf0e/0x32f0 lib/iov_iter.c:185
 copy_page_to_iter+0x43c/0x8b0 lib/iov_iter.c:362
 copy_folio_to_iter include/linux/uio.h:198 [inline]
 filemap_read+0x1b6e/0x2190 mm/filemap.c:2753
 blkdev_read_iter+0x89d/0xa70 block/fops.c:796
 new_sync_read fs/read_write.c:489 [inline]
 vfs_read+0x845/0xef0 fs/read_write.c:570
 ksys_read fs/read_write.c:713 [inline]
 __do_sys_read fs/read_write.c:722 [inline]
 __se_sys_read fs/read_write.c:720 [inline]
 __x64_sys_read+0x1fb/0x4d0 fs/read_write.c:720
 x64_sys_call+0x39db/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 memcpy_to_iter lib/iov_iter.c:65 [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_to_iter+0x12eb/0x32f0 lib/iov_iter.c:185
 copy_page_to_iter+0x43c/0x8b0 lib/iov_iter.c:362
 copy_folio_to_iter include/linux/uio.h:198 [inline]
 shmem_file_read_iter+0x88f/0x1070 mm/shmem.c:3412
 lo_rw_aio+0x113e/0x1700 drivers/block/loop.c:-1
 do_req_filebacked drivers/block/loop.c:-1 [inline]
 loop_handle_cmd drivers/block/loop.c:1866 [inline]
 loop_process_work+0xe30/0x1ee0 drivers/block/loop.c:1901
 loop_rootcg_workfn+0x2b/0x40 drivers/block/loop.c:1932
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

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+0x1710/0x37f0 lib/iov_iter.c:483
 copy_folio_from_iter_atomic include/linux/uio.h:210 [inline]
 generic_perform_write+0x8eb/0x10c0 mm/filemap.c:4121
 shmem_file_write_iter+0x2b7/0x2f0 mm/shmem.c:3464
 lo_rw_aio+0x113e/0x1700 drivers/block/loop.c:-1
 do_req_filebacked drivers/block/loop.c:-1 [inline]
 loop_handle_cmd drivers/block/loop.c:1866 [inline]
 loop_process_work+0xe30/0x1ee0 drivers/block/loop.c:1901
 loop_workfn+0x3e/0x60 drivers/block/loop.c:1925
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was stored to memory at:
 xlog_write_iovec fs/xfs/xfs_log.c:1988 [inline]
 xlog_write_full fs/xfs/xfs_log.c:2023 [inline]
 xlog_write+0x1d5b/0x2380 fs/xfs/xfs_log.c:2292
 xlog_cil_write_chain fs/xfs/xfs_log_cil.c:1084 [inline]
 xlog_cil_push_work+0x2fc0/0x46e0 fs/xfs/xfs_log_cil.c:1436
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was created at:
 slab_free_hook mm/slub.c:2324 [inline]
 slab_free_freelist_hook mm/slub.c:2427 [inline]
 slab_free_bulk mm/slub.c:4680 [inline]
 kmem_cache_free_bulk+0x341/0xf80 mm/slub.c:5257
 kfree_bulk include/linux/slab.h:794 [inline]
 kvfree_rcu_bulk+0x12a/0x4c0 mm/slab_common.c:1516
 kfree_rcu_work+0x326/0x820 mm/slab_common.c:1594
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd59/0xf00 kernel/kthread.c:464
 ret_from_fork+0x6e/0x90 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Bytes 884-887 of 4096 are uninitialized
Memory access of size 4096 starts at ffff888046c0d000
Data copied to user address 000056494b224fc8

CPU: 1 UID: 0 PID: 5966 Comm: udevd Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
=====================================================