Re: [syzbot] [ntfs3?] KMSAN: uninit-value in ntfs_read_bh

[syzbot <syzbot+7a2ba6b7b66340cff225@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in ntfs_read_bh

=====================================================
BUG: KMSAN: uninit-value in ntfs_fix_post_read fs/ntfs3/fsntfs.c:180 [inline]
BUG: KMSAN: uninit-value in ntfs_read_bh+0x1fa/0xdf0 fs/ntfs3/fsntfs.c:1319
 ntfs_fix_post_read fs/ntfs3/fsntfs.c:180 [inline]
 ntfs_read_bh+0x1fa/0xdf0 fs/ntfs3/fsntfs.c:1319
 indx_read+0x44e/0x17b0 fs/ntfs3/index.c:1067
 indx_find+0xd12/0x1440 fs/ntfs3/index.c:1181
 indx_update_dup+0x607/0xf80 fs/ntfs3/index.c:2666
 ni_update_parent+0x12de/0x14b0 fs/ntfs3/frecord.c:3298
 ni_write_inode+0x1cf4/0x1de0 fs/ntfs3/frecord.c:3389
 ntfs3_write_inode+0x94/0xb0 fs/ntfs3/inode.c:1016
 write_inode fs/fs-writeback.c:1503 [inline]
 __writeback_single_inode+0x8da/0x1290 fs/fs-writeback.c:1723
 writeback_sb_inodes+0xa34/0x1c20 fs/fs-writeback.c:1954
 wb_writeback+0x4df/0xcb0 fs/fs-writeback.c:2134
 wb_do_writeback fs/fs-writeback.c:2281 [inline]
 wb_workfn+0x40b/0x1940 fs/fs-writeback.c:2321
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was stored to memory at:
 ntfs_read_run_nb+0x786/0x1070 fs/ntfs3/fsntfs.c:1252
 ntfs_read_bh+0x64/0xdf0 fs/ntfs3/fsntfs.c:1313
 indx_read+0x44e/0x17b0 fs/ntfs3/index.c:1067
 indx_find+0xd12/0x1440 fs/ntfs3/index.c:1181
 indx_update_dup+0x607/0xf80 fs/ntfs3/index.c:2666
 ni_update_parent+0x12de/0x14b0 fs/ntfs3/frecord.c:3298
 ni_write_inode+0x1cf4/0x1de0 fs/ntfs3/frecord.c:3389
 ntfs3_write_inode+0x94/0xb0 fs/ntfs3/inode.c:1016
 write_inode fs/fs-writeback.c:1503 [inline]
 __writeback_single_inode+0x8da/0x1290 fs/fs-writeback.c:1723
 writeback_sb_inodes+0xa34/0x1c20 fs/fs-writeback.c:1954
 wb_writeback+0x4df/0xcb0 fs/fs-writeback.c:2134
 wb_do_writeback fs/fs-writeback.c:2281 [inline]
 wb_workfn+0x40b/0x1940 fs/fs-writeback.c:2321
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 __alloc_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4756
 alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265
 alloc_pages_noprof mm/mempolicy.c:2345 [inline]
 folio_alloc_noprof+0x1db/0x310 mm/mempolicy.c:2352
 filemap_alloc_folio_noprof+0xa6/0x440 mm/filemap.c:1010
 __filemap_get_folio+0xac4/0x1550 mm/filemap.c:1952
 grow_dev_folio fs/buffer.c:1043 [inline]
 grow_buffers fs/buffer.c:1109 [inline]
 __getblk_slow fs/buffer.c:1135 [inline]
 bdev_getblk+0x2c9/0xab0 fs/buffer.c:1437
 __getblk include/linux/buffer_head.h:380 [inline]
 sb_getblk include/linux/buffer_head.h:386 [inline]
 ntfs_get_bh+0x605/0x1190 fs/ntfs3/fsntfs.c:1367
 indx_new+0x1bc/0x780 fs/ntfs3/index.c:955
 indx_insert_into_root+0x2fd1/0x37d0 fs/ntfs3/index.c:1723
 indx_insert_entry+0xe1d/0xee0 fs/ntfs3/index.c:1982
 ntfs_create_inode+0x438d/0x4e50 fs/ntfs3/inode.c:1653
 ntfs_mkdir+0x56/0x70 fs/ntfs3/namei.c:207
 vfs_mkdir+0x4a0/0x780 fs/namei.c:4257
 do_mkdirat+0x529/0x810 fs/namei.c:4280
 __do_sys_mkdirat fs/namei.c:4295 [inline]
 __se_sys_mkdirat fs/namei.c:4293 [inline]
 __x64_sys_mkdirat+0xc6/0x120 fs/namei.c:4293
 x64_sys_call+0x3a81/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:259
 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: 0 UID: 0 PID: 3959 Comm: kworker/u8:20 Not tainted 6.12.0-rc6-syzkaller-00077-g2e1b3cc9d7f7-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: writeback wb_workfn (flush-7:0)
=====================================================


Tested on:

commit:         2e1b3cc9 Merge tag 'arm-fixes-6.12-2' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=114f1d5f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b8a4f4c5365f96b
dashboard link: https://syzkaller.appspot.com/bug?extid=7a2ba6b7b66340cff225
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=120fed5f980000