From: Jeff King <firstname.lastname@example.org> To: "René Scharfe" <email@example.com> Cc: Git Mailing List <firstname.lastname@example.org>, Derrick Stolee <email@example.com>, Junio C Hamano <firstname.lastname@example.org> Subject: Re: [PATCH] gc: fix cast in compare_tasks_by_selection() Date: Tue, 17 Nov 2020 17:30:11 -0500 [thread overview] Message-ID: <20201117223011.GA642234@coredump.intra.peff.net> (raw) In-Reply-To: <email@example.com> On Tue, Nov 17, 2020 at 10:59:49PM +0100, René Scharfe wrote: > compare_tasks_by_selection() is used with QSORT and gets passed pointers > to the elements of "static struct maintenance_task tasks". It casts > the *addresses* of these passed pointers to element pointers, though, > and thus effectively compares some unrelated values from the stack. Fix > the casts to actually compare array elements. > > Detected by USan (make SANITIZE=undefined test). I checked the caller here, and indeed, it's passing an array-of-struct so your patch is doing the right thing (not that I doubted it, but that's what review is for). This qsort void-pointer convention seems to create a lot of confusion (not just the lack of type-safety, but the fact that it's getting a pointer to the element). I felt like we had a discussion about this a while ago, and indeed, I found: https://firstname.lastname@example.org/ The whole sub-thread is worth reading, but the macro you arrived at in: https://email@example.com/ seems pretty reasonable. -Peff
prev parent reply other threads:[~2020-11-17 22:30 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-17 21:59 René Scharfe 2020-11-17 22:30 ` Jeff King [this message]
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style List information: http://vger.kernel.org/majordomo-info.html * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20201117223011.GA642234@coredump.intra.peff.net \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --subject='Re: [PATCH] gc: fix cast in compare_tasks_by_selection()' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
Code repositories for project(s) associated with this inbox: https://80x24.org/mirrors/git.git This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).