From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [IPv6:2a01:7e0:0:424::9]) by lore.proxmox.com (Postfix) with ESMTPS id 33DDD1FF138 for ; Wed, 18 Feb 2026 19:32:51 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 8E9DA3A7E; Wed, 18 Feb 2026 19:33:49 +0100 (CET) Message-ID: Date: Wed, 18 Feb 2026 19:33:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH cluster v2 2/2] cfs lock: unlock when encountering signal To: Fiona Ebner , pve-devel@lists.proxmox.com References: <20260218154438.184685-1-f.ebner@proxmox.com> <20260218154438.184685-3-f.ebner@proxmox.com> Content-Language: en-US From: Thomas Lamprecht In-Reply-To: <20260218154438.184685-3-f.ebner@proxmox.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1771439587391 X-SPAM-LEVEL: Spam detection results: 0 AWL -0.022 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_VALIDITY_CERTIFIED_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_RPBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_SAFE_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Message-ID-Hash: EKJEXOOJ6LFNQONQNZTHSCNV3MVHP563 X-Message-ID-Hash: EKJEXOOJ6LFNQONQNZTHSCNV3MVHP563 X-MailFrom: t.lamprecht@proxmox.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: Proxmox VE development discussion List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Am 18.02.26 um 16:45 schrieb Fiona Ebner: > If the lock directory is not removed after failing because of a > signal, it won't be possible to acquire the lock anymore before the > 120 second timeout imposed on the lock by pmxcfs. This can easily > happen by a second, unrelated task in production and is quite > surprising. Install a signal handler that releases the lock if it was > already acquired. If an old handler is defined, it is invoked, > otherwise the signal is raised again. Just using 'die' would change > the execution flow compared to before the change. > > Signed-off-by: Fiona Ebner > --- > src/PVE/Cluster.pm | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/src/PVE/Cluster.pm b/src/PVE/Cluster.pm > index bdb465f..7165d1c 100644 > --- a/src/PVE/Cluster.pm > +++ b/src/PVE/Cluster.pm > @@ -615,6 +615,22 @@ my $cfs_lock = sub { > > my $is_code_err = 0; > eval { > + # catch signals to release the lock - further defer to old handler if one was set > + my $old_sig; > + $old_sig->{$_} = $SIG{$_} for qw(INT TERM QUIT HUP PIPE); really a non-issue in practice and basically the same thing under the hood, but this could probably just a map, something like (untested): my $old_sig = { map { $_ => $SIG{$_} qw(INT TERM QUIT HUP PIPE) }; > + > + local $SIG{INT} = local $SIG{TERM} = local $SIG{QUIT} = local $SIG{HUP} = > + local $SIG{PIPE} = sub { > + my $signame = $_[0]; > + rmdir $filename if $got_lock; # if we held the lock always unlock again Could be nice to output a warning if above rmdir fails? > + if ($old_sig->{$signame}) { > + $old_sig->{$signame}->(@_); > + } else { > + $SIG{$signame} = 'DEFAULT'; > + POSIX::raise($signame); hmm, this reads alright, but then I'm wondering if it should be added elsewhere? As I found not a single "POSIX::raise" or "raise\(" instance in our perl code inside the /usr/share/perl5/{PVE,Proxmox} directories on a recent PVE 9 system, but we have quite a few signal overrides, and while I did not checked those, I do believe to remember that some of those fallback to the handler defined by the calling site. Describing how exactly the code flow changes would be nice in any case. > + } > + die "interrupted by signal\n"; > + }; > > mkdir $lockdir; >