This is a note to let you know that I've just added the patch titled
fs/ntfs3: don't hold ni_lock when calling truncate_setsize()
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fs-ntfs3-don-t-hold-ni_lock-when-calling-truncate_se.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8bf2fff696584a7be41651408ac8500f3f84dfb3
Author: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Mon Jan 2 23:05:33 2023 +0900
fs/ntfs3: don't hold ni_lock when calling truncate_setsize()
[ Upstream commit 0226635c304cfd5c9db9b78c259cb713819b057e ]
syzbot is reporting hung task at do_user_addr_fault() [1], for there is
a silent deadlock between PG_locked bit and ni_lock lock.
Since filemap_update_page() calls filemap_read_folio() after calling
folio_trylock() which will set PG_locked bit, ntfs_truncate() must not
call truncate_setsize() which will wait for PG_locked bit to be cleared
when holding ni_lock lock.
Link: https://lore.kernel.org/all/00000000000060d41f05f139aa44@xxxxxxxxxx/
Link: https://syzkaller.appspot.com/bug?extid=bed15dbf10294aa4f2ae [1]
Reported-by: syzbot <syzbot+bed15dbf10294aa4f2ae@xxxxxxxxxxxxxxxxxxxxxxxxx>
Debugged-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Co-developed-by: Hillf Danton <hdanton@xxxxxxxx>
Signed-off-by: Hillf Danton <hdanton@xxxxxxxx>
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation")
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index 4f2ffc7ef296..f31c0389a2e7 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -486,10 +486,10 @@ static int ntfs_truncate(struct inode *inode, loff_t new_size)
new_valid = ntfs_up_block(sb, min_t(u64, ni->i_valid, new_size));
- ni_lock(ni);
-
truncate_setsize(inode, new_size);
+ ni_lock(ni);
+
down_write(&ni->file.run_lock);
err = attr_set_size(ni, ATTR_DATA, NULL, 0, &ni->file.run, new_size,
&new_valid, ni->mi.sbi->options->prealloc, NULL);
