From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
[ 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@google.com/ Link: https://syzkaller.appspot.com/bug?extid=bed15dbf10294aa4f2ae [1] Reported-by: syzbot syzbot+bed15dbf10294aa4f2ae@syzkaller.appspotmail.com Debugged-by: Linus Torvalds torvalds@linux-foundation.org Co-developed-by: Hillf Danton hdanton@sina.com Signed-off-by: Hillf Danton hdanton@sina.com Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Fixes: 4342306f0f0d ("fs/ntfs3: Add file operations and implementation") Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 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);