autofs does not expect the pipe it is given to have O_NONBLOCK set - specifically if __kernel_write() in autofs_write() returns -EAGAIN, this is treated as a fatal error and the pipe is closed. For safety autofs should, therefore, clear the O_NONBLOCK flag. Releases of systemd prior to 8th February 2019 used pipe2(p, O_NONBLOCK|O_CLOEXEC) and thus (inadvertently) set this flag. Signed-off-by: NeilBrown <neilb@xxxxxxxx> --- fs/autofs/autofs_i.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h index 3e59f0ed777b..331192bed0d5 100644 --- a/fs/autofs/autofs_i.h +++ b/fs/autofs/autofs_i.h @@ -215,6 +215,8 @@ static inline int autofs_prepare_pipe(struct file *pipe) return -EINVAL; /* We want a packet pipe */ pipe->f_flags |= O_DIRECT; + /* We don't expect -EAGAIN */ + pipe->f_flags &= ~O_NONBLOCK; return 0; } -- 2.14.0.rc0.dirty
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