From nobody Sun Jun 16 12:13:56 2024 X-Original-To: dev-commits-src-main@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4W2Bky35T9z5NhH1; Sun, 16 Jun 2024 12:14:02 +0000 (UTC) (envelope-from peter@holm.cc) Received: from kaskal.pair.com (kaskal.pair.com [209.68.5.173]) (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 did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4W2Bkx0y1Nz3xRr; Sun, 16 Jun 2024 12:14:00 +0000 (UTC) (envelope-from peter@holm.cc) Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of peter@holm.cc designates 209.68.5.173 as permitted sender) smtp.mailfrom=peter@holm.cc Received: from kaskal.pair.com (localhost [127.0.0.1]) by kaskal.pair.com (Postfix) with ESMTP id B5ACCD656D1; Sun, 16 Jun 2024 08:13:59 -0400 (EDT) Received: from Peters-Air (c-x5996a268.customers.hiper-net.dk [89.150.162.104]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by kaskal.pair.com (Postfix) with ESMTPSA id EAD09D8DA5B; Sun, 16 Jun 2024 08:13:58 -0400 (EDT) Date: Sun, 16 Jun 2024 14:13:56 +0200 From: Peter Holm To: Doug Moore Cc: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: Re: git: dd0e5c02ab13 - main - swap_pager: small improvement to find_least Message-ID: References: <202406111638.45BGcnhX099470@gitrepo.freebsd.org> 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 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <202406111638.45BGcnhX099470@gitrepo.freebsd.org> X-Scanned-By: mailmunge 3.11 on 209.68.5.173 X-Spamd-Bar: -- X-Spamd-Result: default: False [-2.86 / 15.00]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.96)[-0.962]; MID_RHS_NOT_FQDN(0.50)[]; R_SPF_ALLOW(-0.20)[+a:kaskal.pair.com]; RCVD_IN_DNSWL_LOW(-0.10)[209.68.5.173:from]; MIME_GOOD(-0.10)[text/plain]; FREEFALL_USER(0.00)[peter]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ASN(0.00)[asn:7859, ipnet:209.68.0.0/18, country:US]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; R_DKIM_NA(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; MISSING_XM_UA(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DMARC_NA(0.00)[holm.cc]; RCVD_TLS_LAST(0.00)[]; MLMMJ_DEST(0.00)[dev-commits-src-all@FreeBSD.org,dev-commits-src-main@FreeBSD.org]; RCPT_COUNT_THREE(0.00)[4] X-Rspamd-Queue-Id: 4W2Bkx0y1Nz3xRr On Tue, Jun 11, 2024 at 04:38:49PM +0000, Doug Moore wrote: > The branch main has been updated by dougm: > > URL: https://cgit.FreeBSD.org/src/commit/?id=dd0e5c02ab13b9eb240d42a71a8f41a8b036bd33 > > commit dd0e5c02ab13b9eb240d42a71a8f41a8b036bd33 > Author: Doug Moore > AuthorDate: 2024-06-11 16:36:23 +0000 > Commit: Doug Moore > CommitDate: 2024-06-11 16:36:23 +0000 > > swap_pager: small improvement to find_least > > Drop an unneeded test, a branch and a needless computation to save a > few instructions. > > Reviewed by: kib > Differential Revision: https://reviews.freebsd.org/D45558 > --- > sys/vm/swap_pager.c | 19 +++++++------------ > 1 file changed, 7 insertions(+), 12 deletions(-) > > diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c > index a07a38481490..15f227457bba 100644 > --- a/sys/vm/swap_pager.c Doug, Here's an easy way to reproduce the issue: 12:43 ~ $ sort /dev/zero & [1] 3650 12:43 ~ $ sort /dev/zero & [2] 3651 12:43 ~ $ sort /dev/zero & [3] 3652 12:43 ~ $ panic: Negative index: -16 cpuid = 8 time = 1718534645 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe010855fa50 vpanic() at vpanic+0x13f/frame 0xfffffe010855fb80 panic() at panic+0x43/frame 0xfffffe010855fbe0 swap_pager_find_least() at swap_pager_find_least+0x105/frame 0xfffffe010855fc20 vm_object_collapse() at vm_object_collapse+0x68b/frame 0xfffffe010855fca0 vmspace_fork() at vmspace_fork+0xb68/frame 0xfffffe010855fd30 fork1() at fork1+0x4f8/frame 0xfffffe010855fda0 sys_fork() at sys_fork+0x54/frame 0xfffffe010855fe00 amd64_syscall() at amd64_syscall+0x158/frame 0xfffffe010855ff30 fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe010855ff30 --- syscall (2, FreeBSD ELF64, fork), rip = 0xaba1c31565a, rsp = 0xaba1b0cecb8, rbp = 0xaba1b0cf220 --- KDB: enter: panic [ thread pid 3653 tid 100349 ] Stopped at $0,0x104d5c2(%rip) db> x/s version version: FreeBSD 15.0-CURRENT #2 main-n270778-d26c565597b8-dirty: Sun Jun 16 12:32:39 CEST 2024\012 pho@mercat1.netperf.freebsd.org:/usr/src/sys/amd64/compile/PHO\012 db> --- a/sys/vm/swap_pager.c +++ b/sys/vm/swap_pager.c @@ -2303,6 +2303,7 @@ swap_pager_find_least(vm_object_t object, vm_pindex_t pindex) if (sb == NULL) return (object->size); for (i = pindex - sb->p; i < SWAP_META_PAGES; i++) { + KASSERT((i >= 0), ("Negative index: %d", i)); if (sb->d[i] != SWAPBLK_NONE) return (sb->p + i); } - Peter