From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org E979D60670 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp3.osuosl.org 3591C605AC DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667150531; 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: in-reply-to:in-reply-to:references:references; bh=xy7b3nRtAL8M7+VedHsmmAKhtOAAl2XLancWVFWUXlg=; b=DprYLL7Egkml7INxACtxk2WTXNU/oB6vcLwo6VYQ8Wn5xXo94eBlZLumhMizda/1lglgEE aDCIkAQbLRE8Y9+U57pXpJ3KxbHyKfFx4J73T8YH8JUODn05TQODtFXgUzM3r/90Aa2KVx YwEs0hV/8gjZYRo8uL1ipAZ89Tn+kak= Message-ID: <27a6a587fee5e9172e41acd16ae1bc1f556fdbd7.camel@redhat.com> From: Paolo Abeni In-Reply-To: <20221028154617.3c63ba68@kernel.org> References: <20221027150525.753064657@goodmis.org> <20221027150928.780676863@goodmis.org> <20221027155513.60b211e2@gandalf.local.home> <20221027163453.383bbf8e@gandalf.local.home> <20221027170720.31497319@gandalf.local.home> <20221027183511.66b058c4@gandalf.local.home> <20221028183149.2882a29b@gandalf.local.home> <20221028154617.3c63ba68@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Subject: Re: [Bridge] [RFC][PATCH v2 19/31] timers: net: Use del_timer_shutdown() before freeing timer List-Id: Linux Ethernet Bridging List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Date: Sun, 30 Oct 2022 17:22:14 -0000 To: Jakub Kicinski , Steven Rostedt Cc: Alexei Starovoitov , Eric Dumazet , Tony Nguyen , linux-afs@lists.infradead.org, Menglong Dong , bridge@lists.linux-foundation.org, Jesse Brandeburg , lvs-devel@vger.kernel.org, coreteam@netfilter.org, tipc-discussion@lists.sourceforge.net, Guenter Roeck , Martin KaFai Lau , Kuniyuki Iwashima , Thomas Gleixner , Mirko Lindner , linux-nfs@vger.kernel.org, Stephen Boyd , linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, "David S. Miller" , netfilter-devel@vger.kernel.org, Linus Torvalds , Pavel Begunkov On Fri, 2022-10-28 at 15:46 -0700, Jakub Kicinski wrote: > On Fri, 28 Oct 2022 18:31:49 -0400 Steven Rostedt wrote: > > Could someone from networking confirm (or deny) that the timer being > > removed in sk_stop_timer() will no longer be used even if del_timer() > > returns false? > > > > net/core/sock.c: > > > > void sk_stop_timer(struct sock *sk, struct timer_list* timer) > > { > > if (del_timer(timer)) > > __sock_put(sk); > > } > > > > If this is the case, then I'll add the following interface: > > > > del_timer_sync_shutdown() // the common case which syncs > > > > del_timer_shutdown() // the uncommon case, that returns immediately > > // used for those cases that add extra code to > > // handle it, like sk_stop_timer() > > Sorry too many bugs at once :) > > FWIW Paolo was saying privately earlier today that he spotted some cases > of reuse, he gave an example of ccid2_hc_tx_packet_recv() For the records, there are other cases, e.g. after sk_stop_timer() in clear_3rdack_retransmission() (mptcp code) the timer can be-rearmed without re-initializing. I *think* there are more of such use in the in ax25/rose code. > So we can't convert all cases of sk_stop_timer() in one fell swoop :( On the positive side, I think converting the sk_stop_timer in inet_csk_clear_xmit_timers() should be safe and should cover the issue reported by Guenter Cheers, Paolo