It hasn't been released yet, but Purism recently smashed their fundraising goal for the Librem 5. From the description linked to below:
> Librem 5, the phone that focuses on security by design and privacy protection by default. Running Free/Libre and Open Source software and a GNU+Linux Operating System designed to create an open development utopia, rather than the walled gardens from all other phone providers.
Are you asking about "linux" meaning a non-Android linux phone?
If you include Android -- I have had a satisfactory experience with both the Samsung Galaxy S6 and LG Nexus 5x. The 5x did bootloop recently but Nexus repaired it (and upgraded to 32GB) beyond the end of their warranty.
> Librem 5, the phone that focuses on security by design and privacy protection by default. Running Free/Libre and Open Source software and a GNU+Linux Operating System designed to create an open development utopia, rather than the walled gardens from all other phone providers.
https://puri.sm/shop/librem-5/