{"thread":{"id":"53357","subject":"Seg Fault on git fetch with fetch.negotiationAlgorithm=skipping","startedAt":"2020-04-30T14:55:13Z","lastAt":"2020-05-01T22:13:37Z","messageCount":4,"participants":["Son Luong Ngoc","Taylor Blau"],"isPatch":false,"patchVersion":null,"patchTotal":null},"messages":[{"id":"396663","messageId":"450D5CC7-113A-40D8-9CD4-53786198526D@gmail.com","threadId":"53357","inReplyTo":null,"subject":"Seg Fault on git fetch with fetch.negotiationAlgorithm=skipping","fromName":"Son Luong Ngoc","fromEmail":"sluongng@gmail.com","sentAt":"2020-04-30T14:55:07Z","receivedAt":"2020-04-30T14:55:13Z","isPatch":false,"sender":{"key":"sluongng@gmail.com","avatar":"https://avatars.githubusercontent.com/u/26684313?v=4"},"body":"Hi folks,\n\nWe recently encountered a segfault during a git fetch\nstrace output could be found https://gist.github.com/sluongng/e48327cc911c617ed2ef8578acc2ea34\n\nThe root cause was due to having `fetch.negotiationAlgorithm=skipping`\nThe repo is about linux.git size with a few NULL commit that we have been using `fsck.skipList` \non both server and client side to skip.\n\nIs this and edge case for the new algorithm?\n\nCheers,\nSon Luong."},{"id":"396693","messageId":"20200430202014.GB2014@syl.local","threadId":"53357","inReplyTo":"450D5CC7-113A-40D8-9CD4-53786198526D@gmail.com","subject":"Re: Seg Fault on git fetch with fetch.negotiationAlgorithm=skipping","fromName":"Taylor Blau","fromEmail":"me@ttaylorr.com","sentAt":"2020-04-30T20:20:14Z","receivedAt":"2020-04-30T20:20:19Z","isPatch":false,"sender":{"key":"me@ttaylorr.com","avatar":"https://avatars.githubusercontent.com/u/301000140?v=4"},"body":"Hi Son,\n\nOn Thu, Apr 30, 2020 at 04:55:07PM +0200, Son Luong Ngoc wrote:\n> Hi folks,\n>\n> We recently encountered a segfault during a git fetch\n> strace output could be found https://gist.github.com/sluongng/e48327cc911c617ed2ef8578acc2ea34\n>\n> The root cause was due to having `fetch.negotiationAlgorithm=skipping`\n> The repo is about linux.git size with a few NULL commit that we have been using `fsck.skipList`\n> on both server and client side to skip.\n\nAre you able to share a core file? If not, it would be very helpful for\nyou to 'git fast-export --anonymize ...' and see if you can reproduce\nthe problem on an anonymized copy of your repository.\n\nI can speculate about the cause of the crash from your strace above, but\na core file would be more helpful.\n\n> Is this and edge case for the new algorithm?\n>\n> Cheers,\n> Son Luong.\n\nThanks,\nTaylor\n"},{"id":"396730","messageId":"BFB84B3B-FB39-4217-A6C6-7599F6F755E2@gmail.com","threadId":"53357","inReplyTo":"20200430202014.GB2014@syl.local","subject":"Re: Seg Fault on git fetch with fetch.negotiationAlgorithm=skipping","fromName":"Son Luong Ngoc","fromEmail":"sluongng@gmail.com","sentAt":"2020-05-01T08:13:43Z","receivedAt":"2020-05-01T08:13:50Z","isPatch":false,"sender":{"key":"sluongng@gmail.com","avatar":"https://avatars.githubusercontent.com/u/26684313?v=4"},"body":"Hi Taylor,\n\n> On Apr 30, 2020, at 22:20, Taylor Blau <me@ttaylorr.com> wrote:\n> \n> Are you able to share a core file? If not, it would be very helpful for\n> you to 'git fast-export --anonymize ...' and see if you can reproduce\n> the problem on an anonymized copy of your repository.\n\nI played a bit with --anonymized yesterday but export/import is slow and I still need to review\nthe history to see whether it could be released.\n\nIt might take more time than just a few days.\n\n> I can speculate about the cause of the crash from your strace above, but\n> a core file would be more helpful.\n\nI have added perf trace2 in https://gist.github.com/sluongng/e48327cc911c617ed2ef8578acc2ea34#file-perf-trace2-L52\n(git version is 2.26.2)\n\nI think this trace is a lot cleared than the strace log.\n\n> Thanks,\n> Taylor\n\nCheers,\nSon Luong."},{"id":"396792","messageId":"20200501221332.GB41612@syl.local","threadId":"53357","inReplyTo":"BFB84B3B-FB39-4217-A6C6-7599F6F755E2@gmail.com","subject":"Re: Seg Fault on git fetch with fetch.negotiationAlgorithm=skipping","fromName":"Taylor Blau","fromEmail":"me@ttaylorr.com","sentAt":"2020-05-01T22:13:32Z","receivedAt":"2020-05-01T22:13:37Z","isPatch":false,"sender":{"key":"me@ttaylorr.com","avatar":"https://avatars.githubusercontent.com/u/301000140?v=4"},"body":"On Fri, May 01, 2020 at 10:13:43AM +0200, Son Luong Ngoc wrote:\n> Hi Taylor,\n>\n> > On Apr 30, 2020, at 22:20, Taylor Blau <me@ttaylorr.com> wrote:\n> >\n> > Are you able to share a core file? If not, it would be very helpful for\n> > you to 'git fast-export --anonymize ...' and see if you can reproduce\n> > the problem on an anonymized copy of your repository.\n>\n> I played a bit with --anonymized yesterday but export/import is slow and I still need to review\n> the history to see whether it could be released.\n>\n> It might take more time than just a few days.\n\nThat's OK. Please let us know when you have it by responding in the\nsub-thread here, and I will be happy to take a look.\n\n> > I can speculate about the cause of the crash from your strace above, but\n> > a core file would be more helpful.\n>\n> I have added perf trace2 in https://gist.github.com/sluongng/e48327cc911c617ed2ef8578acc2ea34#file-perf-trace2-L52\n> (git version is 2.26.2)\n>\n> I think this trace is a lot cleared than the strace log.\n>\n> > Thanks,\n> > Taylor\n>\n> Cheers,\n> Son Luong.\n\nThanks,\nTaylor\n"}]}