On Wed 2018-03-07 16:55:53, Joe Lawrence wrote: > On 03/07/2018 03:20 AM, Petr Mladek wrote: > > The atomic replace allows to create cumulative patches. They > > are useful when you maintain many livepatches and want to remove > > one that is lower on the stack. In addition it is very useful when > > more patches touch the same function and there are dependencies > > between them. > > > > > > Changes against v9: > > > > + Fixed check of valid NOPs for already loaded objects, > > regression introduced in v9 [Joe, Mirek] > > + Allow to replace even disabled patches [Evgenii] > > > > Changes against v8: > > > > + Fixed handling of statically defined struct klp_object > > with empty array of functions [Joe, Mirek] > > + Removed redundant func->new_func assignment for NOPs [Mirek] > > + Improved some wording [Mirek] > > > > [ ... snip ... ] > > Hi Petr, > > I tried updating the test cases I was adding in "[PATCH v0 0/3] > additional cumulative livepatch doc/samples" and although one of the > cases is better than before, I'm running into a new issue: an expected > pre-unpatch callback is not executed (its obj->patched is false). > > Here's the updated test case: > > Test 11 > ------- > > - load livepatch > - load second livepatch (atomic replace) <- callbacks ok > - disable second livepatch <- pre-unpatch skipped > - unload livepatch > - unload second livepatch > > % insmod samples/livepatch/livepatch-callbacks-demo.ko > [ 2306.806046] livepatch: enabling patch 'livepatch_callbacks_demo' > [ 2306.806048] livepatch: 'livepatch_callbacks_demo': initializing patching transition > [ 2306.806083] livepatch_callbacks_demo: pre_patch_callback: vmlinux > [ 2306.806083] livepatch: 'livepatch_callbacks_demo': starting patching transition > [ 2307.743170] livepatch: 'livepatch_callbacks_demo': completing patching transition > [ 2307.743317] livepatch_callbacks_demo: post_patch_callback: vmlinux > [ 2307.743319] livepatch: 'livepatch_callbacks_demo': patching complet > > % insmod samples/livepatch/livepatch-callbacks-demo2.ko replace=1 > [ 2316.161804] livepatch: enabling patch 'livepatch_callbacks_demo2' > [ 2316.161807] livepatch: 'livepatch_callbacks_demo2': initializing patching transition > [ 2316.161842] livepatch_callbacks_demo2: pre_patch_callback: vmlinux > [ 2316.161843] livepatch: 'livepatch_callbacks_demo2': starting patching transition > [ 2317.727141] livepatch: 'livepatch_callbacks_demo2': completing patching transition > [ 2317.727254] livepatch_callbacks_demo2: post_patch_callback: vmlinux > [ 2317.727255] livepatch: 'livepatch_callbacks_demo2': patching complete > > % echo 0 > /sys/kernel/livepatch/livepatch_callbacks_demo2/enabled > [ 2328.995854] livepatch: 'livepatch_callbacks_demo2': initializing unpatching transition > [ 2328.995898] livepatch: 'livepatch_callbacks_demo2': starting unpatching transition > [ 2330.719234] livepatch: 'livepatch_callbacks_demo2': completing unpatching transition > [ 2330.719597] livepatch_callbacks_demo2: post_unpatch_callback: vmlinux > [ 2330.719599] livepatch: 'livepatch_callbacks_demo2': unpatching complete > > % rmmod samples/livepatch/livepatch-callbacks-demo2.ko > % rmmod samples/livepatch/livepatch-callbacks-demo.ko > > Running against v10, callbacks seem to be good up until I disable an > atomic replace patch. My understanding is that the original patch's > unpatch callbacks should be skipped (as they were). I was surprised to > see that atomic replacement patch only ran it's post-unpatch callback. Great catch! I guess that it is caused by the heuristic used in klp_unpatch_object() to decide whether the object is patched or not. We need to change the state only when manipulating the statically defined functions. Thanks a lot for so extensive testing!!! Best Regards, Petr -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
