Hi Maria, I observed severe memory consumption with bird-3.2.0-1.el8.x86_64 and recently updated to bird-3.3.1-2.el8.x86_64 to mitigate the issue. While the update may have resolved the behavior, I am still interested in investigating the root cause.
On several servers, there was consistent, intensive memory growth with RSS reaching up to 100GB. At that stage, birdc became unresponsive, the process showed significant CPU utilization across multiple cores, and BGP neighbors closed their sessions due to timeouts. I had configured debug protocols all; and enabled log rotation, but the process stopped writing to the logs once the memory threshold was reached. I have successfully captured a gcore dump exceeding 100GB. Could you please provide guidance on analyzing this core file to identify the source of the leak? Any advice on how to troubleshoot this effectively would be greatly appreciated. Best regards, Alexander Shevchenko On Fri, Jul 10, 2026 at 5:16 PM Maria Matejka via Bird-users < [email protected]> wrote: > Hi Mariusz, > > On Fri, Jul 10, 2026 at 03:19:03PM +0200, Mariusz Gronczewski wrote: > > I’ve been observing some memory leak (slowly gets to ~30GB across 18 hours > then dies to oomkiller, ~500kB/s growth), how can I debug it furter ? > > That is not an easy task, and I’m a little worried about your actual > memory footprint. This is what I get with one uplink: > > BIRD 3.3.1 ready. > bird> show route count > 1047039 of 1047039 routes for 1047039 networks in table master4 > 245208 of 245208 routes for 245208 networks in table master6 > Total: 1292247 of 1292247 routes for 1292247 networks in 2 tables > bird> show mem > BIRD memory usage > Effective Overhead > Routing tables: 191.7 MB 12.8 MB > Route attributes: 115.3 MB 70.2 MB > Protocols: 371.2 kB 13.6 kB > Current config: 17.0 kB 880.0 B > Standby memory: 0.0 B 33.2 MB > Total: 307.5 MB 116.3 MB > > Active pages: 308.2 MB > Kept free pages: 33.2 MB > Cold free pages: 129.0 MB > Hot page cache depleted while in RCU: 2482 > > birdc > > BIRD 3.3.1 ready. bird> show memory > BIRD memory usage Effective Overhead Routing tables: 6059.3 MB 564.4 MB > Route attributes: 9510.1 MB 565.8 MB Protocols: 22.3 MB 82.9 kB Current > config: 60.8 kB 1232.0 B Standby memory: 0.0 B 32.7 MB Total: 15.2 GB > 1163.0 MB > > Active pages: 16.2 GB Kept free pages: 32.7 MB Cold free pages: 194.2 MB > Hot page cache depleted while in RCU: 66929 > > bird> show route count > 2098594 of 2098594 routes for 1051498 networks in table master4 0 of 0 > routes for 0 networks in table master6 > > This consumption is in itself very fishy. My first look would be into your > filters because 10G in route attributes is probably terribly wrong with > just 2M routes, and there must be *some* reason for that, probably > impossible deduplication. > > Another look would be what happens when you slightly change your import > filter (e.g. by adding yet another community) and see whether the reported > memory footprint raises significantly. Also, it may be handy to set > > debug protocols { states }; > debug channels { routes, states }; > debug tables { routes, states }; > > and see what is happening over time, but as it is slow, it may yield > nothing. > > […] learn all; > > This may play some role but I don’t believe that as the implementation of > the kernel protocol almost didn’t change between 3.1 and 3.3. > > It only started happening once router was enabled (before it was peered > but did not push the routes to kernel table), tho it coincided with upgrade > from 3.1 to 3.3.1 as I hit different bug there . > > I have also tried to disable “export/import table”, “import keep filtered > on” and “allow as sets” just to narrow it down but appears there is no > change > > I would expect that with export/import table off, the memory consumption > would go away. > > By any chance, how much are you calling birdc? We got reported some > memory leaks regarding that. > > Also, I expect that your OSPF is not producing way too many routes, but if > you could elaborate on that number, it may be a clue. > > Also, import keep filtered in OSPF is not needed, there is no benefit > from setting it. > > Thanks for the report! > > – > Maria Matejka (she/her) | BIRD Team Leader | CZ.NIC, z.s.p.o. >
