57ebc6230f
Jakub Kicinski says: ==================== John says: Resolve a series of splats discovered by syzbot and an unhash TLS issue noted by Eric Dumazet. The main issues revolved around interaction between TLS and sockmap tear down. TLS and sockmap could both reset sk->prot ops creating a condition where a close or unhash op could be called forever. A rare race condition resulting from a missing rcu sync operation was causing a use after free. Then on the TLS side dropping the sock lock and re-acquiring it during the close op could hang. Finally, sockmap must be deployed before tls for current stack assumptions to be met. This is enforced now. A feature series can enable it. To fix this first refactor TLS code so the lock is held for the entire teardown operation. Then add an unhash callback to ensure TLS can not transition from ESTABLISHED to LISTEN state. This transition is a similar bug to the one found and fixed previously in sockmap. Then apply three fixes to sockmap to fix up races on tear down around map free and close. Finally, if sockmap is destroyed before TLS we add a new ULP op update to inform the TLS stack it should not call sockmap ops. This last one appears to be the most commonly found issue from syzbot. v4: - fix some use after frees; - disable disconnect work for offload (ctx lifetime is much more complex); - remove some of the dead code which made it hard to understand (for me) that things work correctly (e.g. the checks TLS is the top ULP); - add selftets. ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.