th ESMTP id 4hDPxB5rgpz6mhBT for ; Mon, 03 Aug 2026 18:15:42 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "YR1" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4hDPxB4hMyz3xXV for ; Mon, 03 Aug 2026 18:15:42 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1785780942; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=vWaNYpId6kl+F/UczP8h0QEdhVXswRFns5yKKNQ1A9g=; b=EKtwtVr7v6VvuZBhoO5qEf1Z+tN7I+L5RNtL59PnsYu83AKDsw1Gia16GW4MlMGnLsDSHC TABENPUvl4tJN0V7q9ESFNYWncHT7KG9uZueTyinUFGz8SonmcDDp6FTToLo9EP7ryGDbu 0DMuTAyPW3F+EAFonkJaF8K/4MZSnHhBn7Xg9kDk34aQNxbzn+I8+ZnjMEOnNM2MMK6apo ZMSXat6WBA78i0TCOUCmQFtzkZc6dLE2NUqRxiaMYOMQSDZDJHcSUTGXBrr/RVZlzMABLx 9n9BhLKkMDO1JsfcK1r5CPxYoNrVXdYsWY2/fhHwHFYXvO+XWtBwIwNM4fLUvA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1785780942; a=rsa-sha256; cv=none; b=QP9INTIwgWT+LmlHWfHEn24dZRrxl8lhI5eHdr6yzApInrF7Q9inhxUVrK1EtpKtV9wWDp XcLHaB/Do18oXPrhdYxGW39L2usECdr/sB9j62VU/641sdUoKgug1vhR8Oqp/UXSpk7SPu ocJcvHjeYrjSQlXuqq6CRgD823oY+eWgMDx73zjmh+prUaIj5a4611Cppvd61uKrwK1IDa UW5+zqDQH4tlbTWxBqsW5n//vbr5MOWa38H1P8cJ7seLVmnZq4MnsE8PJCLuCUkn1kQWcx BxX/ocMFfbOq/9spOkYqOSxH9WfIN+P+Fl4UmU5FnOTzTPttUqYHjvoYBLZ2ZQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1785780942; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=vWaNYpId6kl+F/UczP8h0QEdhVXswRFns5yKKNQ1A9g=; b=EysB1Pek67Bt3TQmiK9b+rRDYrmTUyKJRFcuh68daa8zL1xx900ABrmK7J0OmK9hFFqSU3 KOHN4hpC28NCmNsoS+cQkoRI4sFcLG6fvzQ4EYXDOSm2C9joVHVwExYJ8GCOslF9+YTQ7A EZv8ud+xxDcY27c2QX9hYCOC2h9Hw2Vf6soo7GOv1mo0PLLLC92GtWGrXzvc3/LbQAdBvN /LOPD0Z2NSpuDSI1og0j4/ZW35bwA7x0FgBQBVXGcLWP4u7fNippMk94r/ak8+3aRx8qAT WtTUSLOi/NmkSZbftTFmFmhbV2s2hyRCoZVWGXIiQiJQ5KbdY+wE6gtZvek9Hg== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4hDPxB34F0z1BXs for ; Mon, 03 Aug 2026 18:15:42 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 1d7e0 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Mon, 03 Aug 2026 18:15:42 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Cc: Abdelkader Boudih From: Adrian Chadd Subject: git: 9590878fca68 - main - kqueue: stream the knote report instead of buffering all of it List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: adrian X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 9590878fca68e62c63d607da73139698e204d0f0 Auto-Submitted: auto-generated Date: Mon, 03 Aug 2026 18:15:42 +0000 Message-Id: <6a70dace.1d7e0.11c0a964@gitrepo.freebsd.org> The branch main has been updated by adrian: URL: https://cgit.FreeBSD.org/src/commit/?id=9590878fca68e62c63d607da73139698e204d0f0 commit 9590878fca68e62c63d607da73139698e204d0f0 Author: Abdelkader Boudih AuthorDate: 2026-08-03 18:12:19 +0000 Commit: Adrian Chadd CommitDate: 2026-08-03 18:15:15 +0000 kqueue: stream the knote report instead of buffering all of it kern_proc_kqueues_out() sized its intermediate sbuf from the preceding sizing pass, so dumping core for a process with many knotes wired a buffer as large as the entire report. Shrank the intermediate to one page and added a drain that copied into the caller's sbuf up to maxlen, stopping the walk once it was reached. Truncation stayed byte exact. A dump of 384k knotes peaked at 20 KB of M_SBUF instead of 445 MB. Reviewed by: adrian, markj Differential Revision: https://reviews.freebsd.org/D58584 MFC after: 1 week --- sys/kern/kern_event.c | 42 ++++++++++++++++++++++++++++++++++-------- 1 file changed, 34 insertions(+), 8 deletions(-) diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c index 31dab74bd7bd..507451ce4492 100644 --- a/sys/kern/kern_event.c +++ b/sys/kern/kern_event.c @@ -3351,27 +3351,53 @@ kern_proc_kqueues_out1(struct thread *td, struct proc *p, struct sbuf *s, return (fget_remote_foreach(td, p, kern_proc_kqueues_out1_cb, &a)); } +struct kern_proc_kqueues_drain_ctx { + struct sbuf *sb; + size_t remaining; + bool full; +}; + +static int +kern_proc_kqueues_drain(void *arg, const char *data, int len) +{ + struct kern_proc_kqueues_drain_ctx *c; + size_t n; + + c = arg; + n = MIN((size_t)len, c->remaining); + if (n != 0) { + if (sbuf_bcat(c->sb, data, n) != 0) + return (-ENOMEM); + c->remaining -= n; + } + if (c->remaining == 0) { + c->full = true; + return (-ENOSPC); + } + return (len); +} + int kern_proc_kqueues_out(struct proc *p, struct sbuf *sb, size_t maxlen, bool compat32) { + struct kern_proc_kqueues_drain_ctx c; struct sbuf *s, sm; - size_t sb_len; int error; if (maxlen == -1) return (kern_proc_kqueues_out1(curthread, p, sb, compat32)); - if (maxlen == 0) - sb_len = 128; - else - sb_len = maxlen; - s = sbuf_new(&sm, NULL, sb_len + 1, SBUF_FIXEDLEN); + c.sb = sb; + c.remaining = maxlen; + c.full = false; + s = sbuf_new(&sm, NULL, PAGE_SIZE, SBUF_FIXEDLEN); + sbuf_set_drain(s, kern_proc_kqueues_drain, &c); error = kern_proc_kqueues_out1(curthread, p, s, compat32); sbuf_finish(s); - if (error == 0) - sbuf_bcat(sb, sbuf_data(s), MIN(sbuf_len(s), maxlen)); sbuf_delete(s); + if (c.full) + error = 0; return (error); }