From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 7247390BEA for ; Fri, 23 Sep 2022 10:43:32 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 3412621E7E for ; Fri, 23 Sep 2022 10:43:02 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS for ; Fri, 23 Sep 2022 10:43:01 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id D004D44295; Fri, 23 Sep 2022 10:43:00 +0200 (CEST) Message-ID: <501307c2-f2a6-0ff9-7c5c-cccc80c4c352@proxmox.com> Date: Fri, 23 Sep 2022 10:42:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:105.0) Gecko/20100101 Thunderbird/105.0 Content-Language: en-US To: Wolfgang Bumiller Cc: pve-devel@lists.proxmox.com References: <20220922141935.653179-1-d.csapak@proxmox.com> <20220922141935.653179-3-d.csapak@proxmox.com> <20220923083137.evlm3264dakglezg@wobu-vie.proxmox.com> From: Dominik Csapak In-Reply-To: <20220923083137.evlm3264dakglezg@wobu-vie.proxmox.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 1.017 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment KAM_SHORT 0.001 Use of a URL Shortener for very short URL NICE_REPLY_A -1.893 Looks like a legit reply (A) SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [pve-devel] [PATCH qemu-server v2 2/3] qmeventd: cancel 'forced cleanup' when normal cleanup succeeds X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 23 Sep 2022 08:43:32 -0000 On 9/23/22 10:31, Wolfgang Bumiller wrote: > On Thu, Sep 22, 2022 at 04:19:34PM +0200, Dominik Csapak wrote: >> instead of always sending a SIGKILL to the target pid. >> It was not that much of a problem since the timeout previously was 5 >> seconds and we used pifds where possible, thus the chance of killing the >> wrong process was rather slim. >> >> Now we increased the timeout to 60s which makes the race a bit more likely >> (when not using pidfds), so remove it from the 'forced_cleanups' list when >> the normal cleanup succeeds. >> >> Signed-off-by: Dominik Csapak >> --- >> qmeventd/qmeventd.c | 17 +++++++++++++++++ >> 1 file changed, 17 insertions(+) >> >> diff --git a/qmeventd/qmeventd.c b/qmeventd/qmeventd.c >> index 46bc7eb..eebc19d 100644 >> --- a/qmeventd/qmeventd.c >> +++ b/qmeventd/qmeventd.c >> @@ -416,6 +416,22 @@ cleanup_qemu_client(struct Client *client) >> } >> } >> >> +static void >> +remove_cleanup_data(struct CleanupData *data, struct Client *client) { >> + if (data->pid == client->pid) { >> + forced_cleanups = g_slist_remove(forced_cleanups, data); >> + free(data); >> + } >> +} >> + >> +static void >> +remove_from_forced_cleanup(struct Client *client) { >> + if (g_slist_length(forced_cleanups) > 0) { >> + VERBOSE_PRINT("removing %s from forced cleanups\n", client->qemu.vmid); >> + g_slist_foreach(forced_cleanups, (GFunc)remove_cleanup_data, client); > > Foreach + remove feels awkward to me. Sure, it's a linked list and > should be fine™, but I don't like the lack of documentation of > interactions here as a non-glib user. (I mean, eg. for C++ iterator > invalidation is *usually* documented...) just to clarify: it's documented in glibs docs[0]: > It is safe for func to remove the element from list, but it must not modify any part of the list after that element. > > Can't we just give `struct Client` a `struct CleanupData` pointer and > call `g_slist_remove` right here without the iteration? > > Or better yet, your previous idea of dropping `CleanupData` sounds > better. > We should be able to just add `struct Client*` to the list, after all, > according to the glib docs `g_slist_remove` should simply leave the list > unchanged if the data is not part of the list, so when we free up the > `Client` we could even call `g_slist_remove` unconditionally (though > we'll know whether it's in there by having a timeout set then...) > > (or use `g_slist_find_custom`) sounds good to me > >> + } >> +} >> + >> void >> cleanup_client(struct Client *client) >> { >> @@ -442,6 +458,7 @@ cleanup_client(struct Client *client) >> break; >> } >> >> + remove_from_forced_cleanup(client); >> free(client); >> } >> >> -- >> 2.30.2 0: https://docs.gtk.org/glib/type_func.SList.foreach.html