GitHub pull request #3651 of commit 173857dc031db9fdbaa6d8d34ad143a664bddab8, no merge conflicts.sha1origin/pr/3651/mergeghprbActualCommit173857dc031db9fdbaa6d8d34ad143a664bddab8ghprbActualCommitAuthorghprbActualCommitAuthorEmailghprbAuthorRepoGitUrlhttps://github.com/kinvolk/bcc.gitghprbTriggerAuthorghprbTriggerAuthorEmailghprbTriggerAuthorLoginyonghong-songghprbTriggerAuthorLoginMention@yonghong-songghprbPullId3651ghprbTargetBranchmasterghprbSourceBranchmemset-zeroGIT_BRANCHmemset-zeroghprbPullAuthorEmailghprbPullAuthorLogineiffel-flghprbPullAuthorLoginMention@eiffel-flghprbPullDescriptionGitHub pull request #3651 of commit 173857dc031db9fdbaa6d8d34ad143a664bddab8, no merge conflicts.ghprbPullTitletools/capable: Set data to zero before setting fields.ghprbPullLinkhttps://github.com/iovisor/bcc/pull/3651ghprbPullLongDescriptionHi.\r\n\r\n\r\nIn our fork, we added a field to `struct data_t`.\r\nThus, with the actual code and if all fields are not used (*e.g.* by not using `-U` and `-K` options), we would get BPF valider error like the following:\r\n```\r\n...\r\n; bpf_perf_event_output(ctx, bpf_pseudo_fd(1, -1), CUR_CPU_IDENTIFIER, &data, sizeof(data));\r\n74: (bf) r1 = r6\r\n75: (18) r3 = 0xffffffff\r\n77: (b7) r5 = 56\r\n78: (85) call bpf_perf_event_output#25\r\ninvalid indirect read from stack off -80+44 size 56\r\nprocessed 76 insns (limit 1000000) max_states_per_insn 0 total_states 6 peak_states 6 mark_read 6\r\n```\r\n\r\nIn this commit, I added call to `__builtin_memset` to ensure `data` is full of 0, so unaligned access do not cause trouble anymore.\r\nTo be honest, this code is not really needed, as code inside `iovisor/bcc` works.\r\nBut I though it could be a good idea to submit you this modification as it makes the code safer (for example if one day a new field is added to the `struct data_t`).\r\nNote that this comment put me on the way:\r\nhttps://github.com/iovisor/bcc/issues/2623#issuecomment-560214481\r\n\r\nIf you see any way to improve this PR, feel free to share.\r\n\r\n\r\nBest regards.\r\nghprbCommentBody[buildbot, test this please]ghprbGhRepositoryiovisor/bccghprbCredentialsId6d3daf13-69b8-48b1-9c8f-ec5353264113false<a title="tools/capable: Set data to zero before setting fields." href="https://github.com/iovisor/bcc/pull/3651">PR #3651</a>: tools/capable: Set data to ...#117413197597460664bcc-pr #11741174false11749401SUCCESS1634058558291https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/1174/git1174https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=fc25/1174/1174https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=fc26/1174/1174https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=fc27/1174/1174https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=fc28/1174/1174https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=ubuntu1604/1174/1174https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=ubuntu1710/1174/1174https://buildbot.iovisor.org/jenkins/user/andriin/my-views/view/all/job/bcc-pr/label=ubuntu1804/1174/