Public bug reported: SRU Justification
Impact: Starting in eoan -fcf-protection is enabled by default in gcc, see https://wiki.ubuntu.com/ToolChain/CompilerFlags. This option is incompatible with -mindirect-branch, which is used for building kernels with retpoline support. Building a kernel or dkms modules fails without the patch, and during upgrade to eoan we can get failures due to dkms modules failing to build for older kernels with the new compiler. Fix: Backport upstream patch to add -fcf-protection=none to kernel retpoline flags. Test Case: Upgrade from {bionic,diso} to eoan with dkms modules installed. Regression Potential: The patch probes the compiler for support for -fcf-protection and only adds it if the compiler supports it, and =none was the default prior to the change in eoan. It's also been upstream and in eoan for a while now, so it's unlikely to cause any regressions. ** Affects: linux (Ubuntu) Importance: Medium Assignee: Seth Forshee (sforshee) Status: In Progress -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1843291 Title: Add -fcf-protection=none when using retpoline flags Status in linux package in Ubuntu: In Progress Bug description: SRU Justification Impact: Starting in eoan -fcf-protection is enabled by default in gcc, see https://wiki.ubuntu.com/ToolChain/CompilerFlags. This option is incompatible with -mindirect-branch, which is used for building kernels with retpoline support. Building a kernel or dkms modules fails without the patch, and during upgrade to eoan we can get failures due to dkms modules failing to build for older kernels with the new compiler. Fix: Backport upstream patch to add -fcf-protection=none to kernel retpoline flags. Test Case: Upgrade from {bionic,diso} to eoan with dkms modules installed. Regression Potential: The patch probes the compiler for support for -fcf-protection and only adds it if the compiler supports it, and =none was the default prior to the change in eoan. It's also been upstream and in eoan for a while now, so it's unlikely to cause any regressions. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1843291/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
