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://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") --- By the way, ntfs_truncate() is ignoring attr_set_size() failure. Is it OK? fs/ntfs3/file.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c index e5399ebc3a2b..d294cd975688 100644 --- a/fs/ntfs3/file.c +++ b/fs/ntfs3/file.c @@ -390,10 +390,10 @@ 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); -- 2.34.1
