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BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:167 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x376/0x1c60 lib/iov_iter.c:316
 instrument_copy_to_user include/linux/instrumented.h:114 [inline]
 copyout lib/iov_iter.c:167 [inline]
 _copy_to_iter+0x376/0x1c60 lib/iov_iter.c:316
 copy_page_to_iter+0x420/0x880 lib/iov_iter.c:481
 copy_folio_to_iter include/linux/uio.h:185 [inline]
 filemap_read+0xbcc/0x1470 mm/filemap.c:2709
 blkdev_read_iter+0x6c0/0x8e0 block/fops.c:617
 call_read_iter include/linux/fs.h:1871 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x8fc/0xf50 fs/read_write.c:470
 ksys_read+0x20f/0x4c0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x93/0xd0 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was stored to memory at:
 _copy_to_iter+0xc4d/0x1c60 lib/iov_iter.c:316
 copy_page_to_iter+0x420/0x880 lib/iov_iter.c:481
 shmem_file_read_iter+0xac5/0x1310 mm/shmem.c:2696
 do_iter_read+0x61e/0x14a0 fs/read_write.c:795
 vfs_iter_read+0x8e/0xe0 fs/read_write.c:837
 lo_read_simple drivers/block/loop.c:290 [inline]
 do_req_filebacked drivers/block/loop.c:500 [inline]
 loop_handle_cmd drivers/block/loop.c:1915 [inline]
 loop_process_work+0x12cf/0x39a0 drivers/block/loop.c:1950
 loop_rootcg_workfn+0x2b/0x30 drivers/block/loop.c:1981
 process_one_work+0xbf6/0x17c0 kernel/workqueue.c:2600
 worker_thread+0x107e/0x1d60 kernel/workqueue.c:2751
 kthread+0x3e8/0x540 kernel/kthread.c:389
 ret_from_fork+0x57/0x80 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

Uninit was stored to memory at:
 memcpy_from_iter lib/iov_iter.c:380 [inline]
 copy_page_from_iter_atomic+0x1271/0x26d0 lib/iov_iter.c:581
 generic_perform_write+0x4b3/0xc50 mm/filemap.c:3931
 __generic_file_write_iter+0x20a/0x460 mm/filemap.c:4018
 generic_file_write_iter+0x103/0x5b0 mm/filemap.c:4044
 do_iter_write+0x60c/0x1420 fs/read_write.c:860
 vfs_iter_write+0x8e/0xe0 fs/read_write.c:901
 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:1915 [inline]
 loop_process_work+0x2076/0x39a0 drivers/block/loop.c:1950
 loop_rootcg_workfn+0x2b/0x30 drivers/block/loop.c:1981
 process_one_work+0xbf6/0x17c0 kernel/workqueue.c:2600
 worker_thread+0x107e/0x1d60 kernel/workqueue.c:2751
 kthread+0x3e8/0x540 kernel/kthread.c:389
 ret_from_fork+0x57/0x80 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

Uninit was created at:
 __alloc_pages+0x9a4/0xe00 mm/page_alloc.c:4500
 alloc_pages+0xd01/0x1040
 folio_alloc+0x42/0x120 mm/mempolicy.c:2302
 filemap_alloc_folio+0xa5/0x430 mm/filemap.c:979
 __filemap_get_folio+0x908/0x13a0 mm/filemap.c:1933
 ext4_write_begin+0x3e5/0x2220 fs/ext4/inode.c:1147
 ext4_da_write_begin+0x4cd/0xec0 fs/ext4/inode.c:2867
 generic_perform_write+0x3fb/0xc50 mm/filemap.c:3923
 ext4_buffered_write_iter+0x564/0xaa0 fs/ext4/file.c:299
 ext4_file_write_iter+0x20f/0x36b0
 __kernel_write_iter+0x323/0xa40 fs/read_write.c:517
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x593/0xce0 fs/coredump.c:915
 elf_core_dump+0x59e8/0x5c60 fs/binfmt_elf.c:2142
 do_coredump+0x32c8/0x4920 fs/coredump.c:764
 get_signal+0x2185/0x2bc0 kernel/signal.c:2867
 arch_do_signal_or_restart+0x4f/0x920 arch/x86/kernel/signal.c:308
 exit_to_user_mode_loop+0xe8/0x320 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x163/0x220 kernel/entry/common.c:204
 irqentry_exit_to_user_mode+0xd/0x20 kernel/entry/common.c:310
 irqentry_exit+0x16/0x40 kernel/entry/common.c:413
 exc_page_fault+0x494/0x680 arch/x86/mm/fault.c:1545
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:570

Bytes 0-511 of 512 are uninitialized
Memory access of size 512 starts at ffff88809a18a000
Data copied to user address 00005608c9641278

CPU: 0 PID: 5528 Comm: udevd Not tainted 6.5.0-rc6-syzkaller-00038-g16931859a650 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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