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

syzbot
2024-09-10T08:09:05Z

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+0x1eb/0xde0 fs/ntfs3/fsntfs.c:1317
ntfs_fix_post_read fs/ntfs3/fsntfs.c:180 [inline]
ntfs_read_bh+0x1eb/0xde0 fs/ntfs3/fsntfs.c:1317
indx_read+0x44e/0x17b0 fs/ntfs3/index.c:1069
indx_find+0xd12/0x1440 fs/ntfs3/index.c:1183
indx_update_dup+0x607/0xf80 fs/ntfs3/index.c:2668
ni_update_parent+0x12de/0x14b0 fs/ntfs3/frecord.c:3296
ni_write_inode+0x1cf4/0x1de0 fs/ntfs3/frecord.c:3387
ntfs3_write_inode+0x94/0xb0 fs/ntfs3/inode.c:1057
write_inode fs/fs-writeback.c:1497 [inline]
__writeback_single_inode+0x849/0x12c0 fs/fs-writeback.c:1716
writeback_sb_inodes+0xc95/0x1e00 fs/fs-writeback.c:1947
wb_writeback+0x4df/0xea0 fs/fs-writeback.c:2127
wb_do_writeback fs/fs-writeback.c:2274 [inline]
wb_workfn+0x40b/0x1940 fs/fs-writeback.c:2314
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3312
worker_thread+0xea5/0x1520 kernel/workqueue.c:3390
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+0x64/0xde0 fs/ntfs3/fsntfs.c:1313
indx_read+0x44e/0x17b0 fs/ntfs3/index.c:1069
indx_find+0xd12/0x1440 fs/ntfs3/index.c:1183
indx_update_dup+0x607/0xf80 fs/ntfs3/index.c:2668
ni_update_parent+0x12de/0x14b0 fs/ntfs3/frecord.c:3296
ni_write_inode+0x1cf4/0x1de0 fs/ntfs3/frecord.c:3387
ntfs3_write_inode+0x94/0xb0 fs/ntfs3/inode.c:1057
write_inode fs/fs-writeback.c:1497 [inline]
__writeback_single_inode+0x849/0x12c0 fs/fs-writeback.c:1716
writeback_sb_inodes+0xc95/0x1e00 fs/fs-writeback.c:1947
wb_writeback+0x4df/0xea0 fs/fs-writeback.c:2127
wb_do_writeback fs/fs-writeback.c:2274 [inline]
wb_workfn+0x40b/0x1940 fs/fs-writeback.c:2314
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3312
worker_thread+0xea5/0x1520 kernel/workqueue.c:3390
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+0x9d6/0xe70 mm/page_alloc.c:4723
alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2263
alloc_pages_noprof mm/mempolicy.c:2343 [inline]
folio_alloc_noprof+0x1db/0x310 mm/mempolicy.c:2350
filemap_alloc_folio_noprof+0xa6/0x440 mm/filemap.c:1008
__filemap_get_folio+0xa05/0x14b0 mm/filemap.c:1950
grow_dev_folio fs/buffer.c:1047 [inline]
grow_buffers fs/buffer.c:1113 [inline]
__getblk_slow fs/buffer.c:1139 [inline]
bdev_getblk+0x2c9/0xab0 fs/buffer.c:1441
__getblk include/linux/buffer_head.h:381 [inline]
sb_getblk include/linux/buffer_head.h:387 [inline]
ntfs_get_bh+0x605/0x1190 fs/ntfs3/fsntfs.c:1365
indx_new+0x1bc/0x780 fs/ntfs3/index.c:957
indx_insert_into_root+0x2fd1/0x37d0 fs/ntfs3/index.c:1725
indx_insert_entry+0xe1d/0xee0 fs/ntfs3/index.c:1984
ntfs_create_inode+0x4391/0x4df0 fs/ntfs3/inode.c:1694
ntfs_mkdir+0x56/0x70 fs/ntfs3/namei.c:207
vfs_mkdir+0x4a0/0x780 fs/namei.c:4210
do_mkdirat+0x529/0x810 fs/namei.c:4233
__do_sys_mkdirat fs/namei.c:4248 [inline]
__se_sys_mkdirat fs/namei.c:4246 [inline]
__x64_sys_mkdirat+0xc6/0x120 fs/namei.c:4246
x64_sys_call+0x39e5/0x3c10 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: 3128 Comm: kworker/u8:10 Not tainted 6.11.0-rc1-syzkaller-00017-g689ecd06ef8d-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: writeback wb_workfn (flush-7:0)
=====================================================

Tested on:

commit: 689ecd06 fs/ntfs3: Rename ntfs3_setattr into ntfs_seta..
git tree: https://github.com/Paragon-Software-Group/linux-ntfs3.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=1626f43b980000
kernel config: https://syzkaller.appspot.com/x/.config?x=2dda45ca15df5ccb
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=163af43b980000