This is just a safety precaution to avoid checking flags on memory that was initialized on the user space side. libfuse zeroes struct fuse_init_out outarg, but this is not guranteed to be done in all implementations. Better is to act on flags and to only apply flags2 when FUSE_INIT_EXT is set. There is a risk with this change, though - it might break existing user space libraries, which are already using flags2 without setting FUSE_INIT_EXT. The corresponding libfuse patch is here https://github.com/libfuse/libfuse/pull/662 Signed-off-by: Bernd Schubert <bschubert@xxxxxxx> --- fs/fuse/inode.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 9ee36aa73251..8115a06d5fbb 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1115,7 +1115,10 @@ static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, process_init_limits(fc, arg); if (arg->minor >= 6) { - u64 flags = arg->flags | (u64) arg->flags2 << 32; + u64 flags = arg->flags; + + if (flags & FUSE_INIT_EXT) + flags |= (u64) arg->flags2 << 32; ra_pages = arg->max_readahead / PAGE_SIZE; if (flags & FUSE_ASYNC_READ)
