RE: [syzbot] [exfat?] KMSAN: uninit-value in __exfat_get_dentry_set
From: Yuezhang.Mo@xxxxxxxx
Date: Mon Oct 14 2024 - 03:28:33 EST
#syz test
On Sat, Oct 5, 2024 at 8:02 PM syzbot <syzbot+01218003be74b5e1213a@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: e32cde8d2bd7 Merge tag 'sched_ext-for-6.12-rc1-fixes-1'
> of..
> git tree: upstream
> console+strace:
> https://urldefense.com/v3/__https://syzkaller.appspot.com/x/log.txt?x=16cf7d
> d0580000__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6NhWwWIWcja8UUVBXZY
> WyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0CGeGE0kSF4M2hOwVy5
> 7mr5yQIbTA6$
> kernel config:
> https://urldefense.com/v3/__https://syzkaller.appspot.com/x/.config?x=b1fd45
> f2013d812f__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6NhWwWIWcja8UUVBX
> ZYWyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0CGeGE0kSF4M2hOwV
> y57mr50IfSXOd$
> dashboard link:
> https://urldefense.com/v3/__https://syzkaller.appspot.com/bug?extid=012180
> 03be74b5e1213a__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6NhWwWIWcja8U
> UVBXZYWyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0CGeGE0kSF4M2h
> OwVy57mr5-IoYOKx$
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian)
> 2.40
> syz repro:
> https://urldefense.com/v3/__https://syzkaller.appspot.com/x/repro.syz?x=11cf
> 7dd0580000__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6NhWwWIWcja8UUVB
> XZYWyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0CGeGE0kSF4M2hOw
> Vy57mr58TvVCus$
> C reproducer:
> https://urldefense.com/v3/__https://syzkaller.appspot.com/x/repro.c?x=11d06
> 580580000__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6NhWwWIWcja8UUVBXZ
> YWyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0CGeGE0kSF4M2hOwVy
> 57mr5w2Sgp57$
>
> Downloadable assets:
> disk image:
> https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/16
> d4da549bf4/disk-e32cde8d.raw.xz__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6
> NhWwWIWcja8UUVBXZYWyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0
> CGeGE0kSF4M2hOwVy57mr54CRCyjy$
> vmlinux:
> https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/a01
> bc9a0e174/vmlinux-e32cde8d.xz__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6N
> hWwWIWcja8UUVBXZYWyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0C
> GeGE0kSF4M2hOwVy57mr5_9fwsZ2$
> kernel image:
> https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/93f
> 4dfad6909/bzImage-e32cde8d.xz__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6N
> hWwWIWcja8UUVBXZYWyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0C
> GeGE0kSF4M2hOwVy57mr54HU84Yj$
> mounted in repro:
> https://urldefense.com/v3/__https://storage.googleapis.com/syzbot-assets/43
> 3ba0700154/mount_0.gz__;!!JmoZiZGBv3RvKRSx!_EFM31JxDI_sBC6NhWwWI
> Wcja8UUVBXZYWyhK0O9vUuSsqy-ZOla4TuepNTA3X-btBmzePMIOD0CGeGE0k
> SF4M2hOwVy57mr51x55siW$
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by:
> mailto:syzbot+01218003be74b5e1213a@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> exFAT-fs (loop0): failed to load upcase table (idx : 0x00010000, chksum :
> 0x726052d3, utbl_chksum : 0xe619d30d)
> =====================================================
> BUG: KMSAN: uninit-value in __exfat_get_dentry_set+0x10ca/0x14d0
> fs/exfat/dir.c:804
> __exfat_get_dentry_set+0x10ca/0x14d0 fs/exfat/dir.c:804
> exfat_get_dentry_set+0x58/0xec0 fs/exfat/dir.c:859
> __exfat_write_inode+0x3c1/0xe30 fs/exfat/inode.c:46
> __exfat_truncate+0x7f3/0xbb0 fs/exfat/file.c:211
> exfat_truncate+0xee/0x2a0 fs/exfat/file.c:257
> exfat_write_failed fs/exfat/inode.c:421 [inline]
> exfat_direct_IO+0x5a3/0x900 fs/exfat/inode.c:485
> generic_file_direct_write+0x275/0x6a0 mm/filemap.c:3977
> __generic_file_write_iter+0x242/0x460 mm/filemap.c:4141
> exfat_file_write_iter+0x894/0xfb0 fs/exfat/file.c:598
> do_iter_readv_writev+0x88a/0xa30
> vfs_writev+0x56a/0x14f0 fs/read_write.c:1064
> do_pwritev fs/read_write.c:1165 [inline]
> __do_sys_pwritev2 fs/read_write.c:1224 [inline]
> __se_sys_pwritev2+0x280/0x470 fs/read_write.c:1215
> __x64_sys_pwritev2+0x11f/0x1a0 fs/read_write.c:1215
> x64_sys_call+0x2edb/0x3ba0
> arch/x86/include/generated/asm/syscalls_64.h:329
> 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
>
> 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+0xe53/0x2b30 lib/iov_iter.c:185
> copy_page_to_iter+0x419/0x880 lib/iov_iter.c:362
> shmem_file_read_iter+0xa09/0x12b0 mm/shmem.c:3167
> do_iter_readv_writev+0x88a/0xa30
> vfs_iter_read+0x278/0x760 fs/read_write.c:923
> lo_read_simple drivers/block/loop.c:283 [inline]
> do_req_filebacked drivers/block/loop.c:516 [inline]
> loop_handle_cmd drivers/block/loop.c:1910 [inline]
> loop_process_work+0x20fc/0x3750 drivers/block/loop.c:1945
> loop_rootcg_workfn+0x2b/0x40 drivers/block/loop.c:1976
> 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:
> 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+0x12b7/0x3100 lib/iov_iter.c:481
> copy_folio_from_iter_atomic include/linux/uio.h:201 [inline]
> generic_perform_write+0x8d1/0x1080 mm/filemap.c:4066
> shmem_file_write_iter+0x2ba/0x2f0 mm/shmem.c:3221
> do_iter_readv_writev+0x88a/0xa30
> vfs_iter_write+0x44d/0xd40 fs/read_write.c:988
> lo_write_bvec drivers/block/loop.c:243 [inline]
> lo_write_simple drivers/block/loop.c:264 [inline]
> do_req_filebacked drivers/block/loop.c:511 [inline]
> loop_handle_cmd drivers/block/loop.c:1910 [inline]
> loop_process_work+0x15e6/0x3750 drivers/block/loop.c:1945
> loop_rootcg_workfn+0x2b/0x40 drivers/block/loop.c:1976
> 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+0x9d6/0xe70 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
> block_write_begin+0x6e/0x2b0 fs/buffer.c:2226
> exfat_write_begin+0xfb/0x400 fs/exfat/inode.c:434
> exfat_extend_valid_size fs/exfat/file.c:553 [inline]
> exfat_file_write_iter+0x474/0xfb0 fs/exfat/file.c:588
> do_iter_readv_writev+0x88a/0xa30
> vfs_writev+0x56a/0x14f0 fs/read_write.c:1064
> do_pwritev fs/read_write.c:1165 [inline]
> __do_sys_pwritev2 fs/read_write.c:1224 [inline]
> __se_sys_pwritev2+0x280/0x470 fs/read_write.c:1215
> __x64_sys_pwritev2+0x11f/0x1a0 fs/read_write.c:1215
> x64_sys_call+0x2edb/0x3ba0
> arch/x86/include/generated/asm/syscalls_64.h:329
> 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: 5188 Comm: syz-executor221 Not tainted
> 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 09/13/2024
> =====================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See
> https://urldefense.com/v3/__https://goo.gl/tpsmEJ__;!!JmoZiZGBv3RvKRSx!_E
> FM31JxDI_sBC6NhWwWIWcja8UUVBXZYWyhK0O9vUuSsqy-ZOla4TuepNTA3X-
> btBmzePMIOD0CGeGE0kSF4M2hOwVy57mr50hLBEHu$ for more information
> about syzbot.
> syzbot engineers can be reached at mailto:syzkaller@xxxxxxxxxxxxxxxx.
>
> syzbot will keep track of this issue. See:
> https://urldefense.com/v3/__https://goo.gl/tpsmEJ*status__;Iw!!JmoZiZGBv3R
> vKRSx!_EFM31JxDI_sBC6NhWwWIWcja8UUVBXZYWyhK0O9vUuSsqy-ZOla4Tu
> epNTA3X-btBmzePMIOD0CGeGE0kSF4M2hOwVy57mr55Eybub8$ for how to
> communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
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> If you attach or paste a git patch, syzbot will apply it before testing.
>
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>
> If you want to undo deduplication, reply with:
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From 31f61e9fd68258588910c05dcbd50af381fe8b96 Mon Sep 17 00:00:00 2001
From: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
Date: Mon, 14 Oct 2024 12:52:28 +0800
Subject: [PATCH] exfat: do not update ->valid_size in exfat_get_block() if map
for direct write
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
---
fs/exfat/inode.c | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
index d338a59c27f7..6e1312f30846 100644
--- a/fs/exfat/inode.c
+++ b/fs/exfat/inode.c
@@ -261,8 +261,8 @@ static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
return 0;
}
-static int exfat_get_block(struct inode *inode, sector_t iblock,
- struct buffer_head *bh_result, int create)
+static int __exfat_get_block(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create, bool dio)
{
struct exfat_inode_info *ei = EXFAT_I(inode);
struct super_block *sb = inode->i_sb;
@@ -323,8 +323,10 @@ static int exfat_get_block(struct inode *inode, sector_t iblock,
/* The area has not been written, map and mark as new. */
set_buffer_new(bh_result);
- ei->valid_size = EXFAT_BLK_TO_B(iblock + max_blocks, sb);
- mark_inode_dirty(inode);
+ if (!dio) {
+ ei->valid_size = EXFAT_BLK_TO_B(iblock + max_blocks, sb);
+ mark_inode_dirty(inode);
+ }
} else {
valid_blks = EXFAT_B_TO_BLK(ei->valid_size, sb);
@@ -381,6 +383,18 @@ static int exfat_get_block(struct inode *inode, sector_t iblock,
return err;
}
+static int exfat_get_block(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ return __exfat_get_block(inode, iblock, bh_result, create, false);
+}
+
+static int exfat_get_block_for_dio(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ return __exfat_get_block(inode, iblock, bh_result, create, true);
+}
+
static int exfat_read_folio(struct file *file, struct folio *folio)
{
return mpage_read_folio(folio, exfat_get_block);
@@ -479,7 +493,7 @@ static ssize_t exfat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
* Need to use the DIO_LOCKING for avoiding the race
* condition of exfat_get_block() and ->truncate().
*/
- ret = blockdev_direct_IO(iocb, inode, iter, exfat_get_block);
+ ret = blockdev_direct_IO(iocb, inode, iter, exfat_get_block_for_dio);
if (ret < 0) {
if (rw == WRITE && ret != -EIOCBQUEUED)
exfat_write_failed(mapping, size);
--
2.34.1