On Tue, Apr 14, 2020 at 08:57:15PM -0400, Joe Lawrence wrote: > On 4/14/20 12:28 PM, Josh Poimboeuf wrote: > > Better late than never, these patches add simplifications and > > improvements for some issues Peter found six months ago, as part of his > > non-writable text code (W^X) cleanups. > > > > Highlights: > > > > - Remove the livepatch arch-specific .klp.arch sections, which were used > > to do paravirt patching and alternatives patching for livepatch > > replacement code. > > > > - Add support for jump labels in patched code. > > Re: jump labels and late-module patching support... > > Is there still an issue of a non-exported static key defined in a > to-be-patched module referenced and resolved via klp-relocation when the > livepatch module is loaded first? (Basically the same case I asked Petr > about in his split livepatch module PoC. [1]) > > Or should we declare this an invalid klp-relocation use case and force the > livepatch author to use static_key_enabled()? > > [1] https://lore.kernel.org/lkml/20200407205740.GA17061@xxxxxxxxxx/ Right, if the static key lives in a module, then it's still not possible for a jump label to use it. I added a check in kpatch-build to block that case and suggest static_key_enabled() instead. I don't know what the solution is, other than getting rid of late module patching. I confess I haven't looked at Petr's patches due to other distractions, but I plan to soon. -- Josh
