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Tue, 17 Feb 2026 17:19:57 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id XPzXHz2jlGlZEQAAD6G6ig (envelope-from ); Tue, 17 Feb 2026 17:19:57 +0000 Message-ID: <2677c7cb-efb7-4f19-8000-4ed127f33847@suse.de> Date: Tue, 17 Feb 2026 18:19:46 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [net?] possible deadlock in inet6_getname To: Gerd Rausch , Eric Dumazet , syzbot Cc: davem@davemloft.net, dsahern@kernel.org, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com References: <698f15e6.a70a0220.2c38d7.00c1.GAE@google.com> <50e88063-14fb-4912-a65d-172a85def1ee@oracle.com> <1c5ce96c-3b01-44e0-8dc9-5c54e504cb95@suse.de> <4cd4099b-328d-45eb-990d-793df79cd639@oracle.com> Content-Language: en-US From: Fernando Fernandez Mancera In-Reply-To: <4cd4099b-328d-45eb-990d-793df79cd639@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Score: -2.80 X-Spam-Level: X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_ALL(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; ARC_NA(0.00)[]; TAGGED_RCPT(0.00)[5efae91f60932839f0a5]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; RCPT_COUNT_SEVEN(0.00)[11]; MID_RHS_MATCH_FROM(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:mid,imap1.dmz-prg2.suse.org:helo]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; SUBJECT_HAS_QUESTION(0.00)[] X-Spam-Flag: NO On 2/17/26 6:13 PM, Gerd Rausch wrote: > Hi, > > On 2026-02-17 09:03, Fernando Fernandez Mancera wrote: >>> rds_tcp_conn_slots_available() can also be called from >>> rds_conn_shutdown(), >>> where no "rds_tcp.ko" backend specific lock is held. >>> >> >> >> AFAICS, from rds_conn_shutdown() path rds_tcp_conn_slots_available() >> is called with fan-out argument as false. Therefore, no need to get >> the peer source port. >> >> I think that should be fine. >> > > True, but IMHO subtle and error-prone. > > If someone were to change the code to pass in "fan_out == true" > from a context not already holding a socket lock, > would they remember to change rds_tcp_conn_slots_available() > to acquire that lock? > Usually kernel requires the developer to understand when do they need to acquire a lock or not. Anyway, what would you suggest? To check whether we have acquired the lock or not and do it conditionally? Thanks, Fernando. > Thanks, > >   Gerd > >