Hello, syzbot found the following issue on: HEAD commit: 7cccf3be6dcb string: use __builtin_memcpy() in strlcpy/str.. git tree: https://github.com/google/kmsan.git master console output: https://syzkaller.appspot.com/x/log.txt?x=1228ed9b280000 kernel config: https://syzkaller.appspot.com/x/.config?x=5e9e8900159378 dashboard link: https://syzkaller.appspot.com/bug?extid=17a061f6132066e9fb95 compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/5e08b958e39c/disk-7cccf3be.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/9003cbdf6555/vmlinux-7cccf3be.xz kernel image: https://storage.googleapis.com/syzbot-assets/192dba10f451/bzImage-7cccf3be.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+17a061f6132066e9fb95@xxxxxxxxxxxxxxxxxxxxxxxxx ===================================================== 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:169 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x420/0x1d00 lib/iov_iter.c:536 instrument_copy_to_user include/linux/instrumented.h:114 [inline] copyout lib/iov_iter.c:169 [inline] _copy_to_iter+0x420/0x1d00 lib/iov_iter.c:536 copy_page_to_iter+0x46e/0x920 lib/iov_iter.c:742 copy_folio_to_iter include/linux/uio.h:197 [inline] filemap_read+0xc37/0x14f0 mm/filemap.c:2742 blkdev_read_iter+0xa1b/0xbc0 block/fops.c:606 call_read_iter include/linux/fs.h:1862 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x933/0xe40 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+0xc9e/0x1d00 lib/iov_iter.c:536 copy_page_to_iter+0x46e/0x920 lib/iov_iter.c:742 shmem_file_read_iter+0xac2/0x1310 mm/shmem.c:2696 do_iter_read+0xd0a/0x1340 fs/read_write.c:795 vfs_iter_read+0x88/0xe0 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:1888 [inline] loop_process_work+0x12c9/0x3990 drivers/block/loop.c:1923 loop_rootcg_workfn+0x2b/0x30 drivers/block/loop.c:1954 process_one_work+0xb0d/0x1410 kernel/workqueue.c:2405 worker_thread+0x107e/0x1d60 kernel/workqueue.c:2552 kthread+0x3e8/0x540 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Uninit was stored to memory at: memcpy_from_iter lib/iov_iter.c:639 [inline] copy_page_from_iter_atomic+0x1271/0x26d0 lib/iov_iter.c:872 generic_perform_write+0x4a2/0xbb0 mm/filemap.c:3931 __generic_file_write_iter+0x393/0x920 mm/filemap.c:4051 generic_file_write_iter+0x103/0x5b0 mm/filemap.c:4083 do_iter_write+0x605/0x1310 fs/read_write.c:860 vfs_iter_write+0x88/0xe0 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:1888 [inline] loop_process_work+0x206d/0x3990 drivers/block/loop.c:1923 loop_workfn+0x48/0x60 drivers/block/loop.c:1947 process_one_work+0xb0d/0x1410 kernel/workqueue.c:2405 worker_thread+0x107e/0x1d60 kernel/workqueue.c:2552 kthread+0x3e8/0x540 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Uninit was stored to memory at: copy_to_dinode+0x88d/0xb40 fs/jfs/jfs_imap.c:3148 diWrite+0x1bf0/0x1f00 fs/jfs/jfs_imap.c:786 txCommit+0xe52/0x8f40 fs/jfs/jfs_txnmgr.c:1250 __jfs_xattr_set+0x1b3/0x1f0 fs/jfs/xattr.c:919 jfs_xattr_set+0x79/0x90 fs/jfs/xattr.c:941 __vfs_setxattr+0x7aa/0x8b0 fs/xattr.c:201 __vfs_setxattr_noperm+0x24f/0xa30 fs/xattr.c:235 __vfs_setxattr_locked+0x441/0x480 fs/xattr.c:296 vfs_setxattr+0x294/0x650 fs/xattr.c:322 do_setxattr fs/xattr.c:630 [inline] setxattr+0x45f/0x540 fs/xattr.c:653 __do_sys_fsetxattr fs/xattr.c:709 [inline] __se_sys_fsetxattr+0x2bb/0x420 fs/xattr.c:698 __ia32_sys_fsetxattr+0xe3/0x150 fs/xattr.c:698 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178 do_fast_syscall_32+0x37/0x80 arch/x86/entry/common.c:203 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:246 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Uninit was stored to memory at: ea_put fs/jfs/xattr.c:637 [inline] __jfs_setxattr+0x1877/0x1b90 fs/jfs/xattr.c:783 __jfs_xattr_set+0xe6/0x1f0 fs/jfs/xattr.c:917 jfs_xattr_set+0x79/0x90 fs/jfs/xattr.c:941 __vfs_setxattr+0x7aa/0x8b0 fs/xattr.c:201 __vfs_setxattr_noperm+0x24f/0xa30 fs/xattr.c:235 __vfs_setxattr_locked+0x441/0x480 fs/xattr.c:296 vfs_setxattr+0x294/0x650 fs/xattr.c:322 do_setxattr fs/xattr.c:630 [inline] setxattr+0x45f/0x540 fs/xattr.c:653 __do_sys_fsetxattr fs/xattr.c:709 [inline] __se_sys_fsetxattr+0x2bb/0x420 fs/xattr.c:698 __ia32_sys_fsetxattr+0xe3/0x150 fs/xattr.c:698 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178 do_fast_syscall_32+0x37/0x80 arch/x86/entry/common.c:203 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:246 entry_SYSENTER_compat_after_hwframe+0x70/0x82 Local variable ea_buf created at: __jfs_setxattr+0x5d/0x1b90 fs/jfs/xattr.c:660 __jfs_xattr_set+0xe6/0x1f0 fs/jfs/xattr.c:917 Bytes 3689-3691 of 4096 are uninitialized Memory access of size 4096 starts at ffff88815f2ee000 Data copied to user address 000055a672e8dc78 CPU: 1 PID: 7649 Comm: udevd Not tainted 6.4.0-rc6-syzkaller-g7cccf3be6dcb #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 ===================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to change bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
