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[73.158.218.242]) by smtp.gmail.com with UTF8SMTPSA id d9443c01a7336-23506d22d0dsm14304355ad.257.2025.05.29.09.45.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 May 2025 09:45:11 -0700 (PDT) Date: Thu, 29 May 2025 09:45:10 -0700 From: Stanislav Fomichev To: Jakub Kicinski Cc: syzbot , davem@davemloft.net, edumazet@google.com, horms@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [net?] possible deadlock in rtnl_newlink Message-ID: References: <683837bf.a00a0220.52848.0003.GAE@google.com> <20250529091003.3423378b@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250529091003.3423378b@kernel.org> On 05/29, Jakub Kicinski wrote: > On Thu, 29 May 2025 08:59:43 -0700 Stanislav Fomichev wrote: > > So this is internal WQ entry lock that is being reordered with rtnl > > lock. But looking at process_one_work, I don't see actual locks, mostly > > lock_map_acquire/lock_map_release calls to enforce some internal WQ > > invariants. Not sure what to do with it, will try to read more. > > Basically a flush_work() happens while holding rtnl_lock, > but the work itself takes that lock. It's a driver bug. e400c7444d84 ("e1000: Hold RTNL when e1000_down can be called") ? I think similar things (but wrt netdev instance lock) are happening with iavf: iavf_remove calls cancel_work_sync while holding the instance lock and the work callbacks grab the instance lock as well :-/