Array of group descriptor block buffers can get rather large. In theory in can reach 1MB for perfectly valid filesystem and even more for maliciously crafted ones. Use kvmalloc() to allocate the array to avoid straining memory allocator with large order allocations unnecessarily. Reported-by: syzbot+0f2f7e65a3007d39539f@syzkaller.appspotmail.com Signed-off-by: Jan Kara <jack@suse.cz>