On Thu, Sep 03, 2020 at 02:28:37PM +0800, kernel test robot wrote: > Greeting, > > FYI, we noticed the following commit (built with gcc-9): > > commit: c0aaf9b7a114f6b75e0da97be7d99c102347a751 ("btrfs: switch to > iomap_dio_rw() for dio") > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
That's probably the O_DIRECT + O_(D)SYNC deadlock that was found recently. One of the cases in diotest4 does open(filename, O_DIRECT | O_RDWR | O_SYNC) Fix is work in progress, thanks for the report.