fs/ntfs3: don't hold ni_lock when calling truncate_setsize()
authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Mon, 2 Jan 2023 14:05:33 +0000 (23:05 +0900)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 2 Jan 2023 18:31:09 +0000 (10:31 -0800)
commit0226635c304cfd5c9db9b78c259cb713819b057e
treed953d1f6de947ca0a6e29ddedfbbcaa16afa2bfd
parent88603b6dc419445847923fcb7fe5080067a30f98
fs/ntfs3: don't hold ni_lock when calling truncate_setsize()

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
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>
fs/ntfs3/file.c