{"schema":"threatline.record/2","record":{"id":"CVE-2026-98069","aliases":[],"summary":"net/rds: acquire the fastpath locks in rds_conn_shutdown()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: acquire the fastpath locks in rds_conn_shutdown()\n\nrds_conn_shutdown() quiesces the transmit and receive-refill paths by\nwaiting for RDS_IN_XMIT and RDS_RECV_REFILL to be sampled clear, and\nthen runs the transport shutdown and rds_conn_path_reset().  Sampling\nthe bits clear is not the same as owning them: the moment after the\nwait_event() returns, rds_send_xmit() can re-acquire RDS_IN_XMIT (or\nrds_ib_recv_refill() can re-acquire RDS_RECV_REFILL) and run\nconcurrently with the teardown.\n\nThe sender does recheck the connection state after taking the lock,\nbut that recheck is a classic store-buffering pattern: teardown writes\nthe state and reads the bit while the sender writes the bit and reads\nthe state.  acquire_in_xmit() is only an acquire operation, so on\nweakly ordered architectures both sides can miss each other's write,\nand the transmit path then runs while the transport zeroes its rings\n(e.g. rds_ib_ring_init()) and rds_send_path_reset() rewrites the\ntransmit state under it.\n\nOracle UEK fixed the same class of crashes - a 14-year tail of\nBUG_ON()s in rds_ib_sub_signaled(), unexpected op-codes and NULL\ndereferences in rds_ib_send_cqe_handler() during failover testing -\nby making the teardown path *acquire* the fastpath bit locks instead\nof testing them (\"rds: Make sure transmit path and connection\ntear-down does not run concurrently\").  Ownership of a single word is\ndecided by RMW atomicity, so no cross-variable ordering is needed.\n\nDo the same here: take both locks before calling the transport\nshutdown, hold them across rds_conn_path_reset(), and release them\nexplicitly with a wake-up afterwards.  Both are released with\nclear_bit_unlock(), so that the ring re-initialization done by the\ntransport shutdown and the transmit state rewritten by\nrds_send_path_reset() are ordered before either bit is seen clear by\nthe next acquire_in_xmit() or acquire_refill().\n\nThe fastpath users of these bits - rds_send_xmit() and\nrds_ib_recv_refill() - are trylock style and back off while teardown\nowns the locks, so no new lock dependency is introduced for them.\nrds_tcp_reset_callbacks() is different: since the previous patch it\nacquires RDS_IN_XMIT as well, and it blocks doing so, so its wait now\nspans the teardown instead of at most one send batch.  That waiter\nruns from rds_tcp_accept_one() on the single-threaded krdsd workqueue\nand holds rds_tcp_accept_lock and t_conn_path_lock while it waits, so\na duelling SYN accepted while its path is being torn down parks\naccept processing for the duration of the teardown - for TCP bounded\nby the (up to 5 s) drain loop in rds_tcp_conn_path_shutdown().  An IB\npath's drain in rds_ib_conn_path_shutdown() has no round cap, but no\nblocking waiter either: rds_tcp_reset_callbacks() is the only blocking\nacquirer of these bits and waits only on its own TCP path, and the\nfastpaths are trylock-and-back-off on both transports, so a long IB\ndrain lengthens only that path's own quiesce.  The\nwindow is narrow: the accept-side state check has to pass before the\nteardown moves the path to RDS_CONN_DISCONNECTING.\n\nBecause krdsd is a single global workqueue, everything else queued\nthere - accept processing for other connections and network\nnamespaces, and the flush_workqueue(rds_wq) in rds_tcp_listen_stop()\nduring namespace teardown - waits behind the parked accept worker for\nthat time.  It cannot deadlock, although the waits do point at each\nother: the teardown blocks until the bit's holder releases it, and\nthe holder may be that krdsd accept worker.  The holder finishes\nwithout needing anything the teardown owns: the sync cancels\nrds_tcp_reset_callbacks() issues target cp_send_w and cp_recv_w on\nthe path's ordered cp_wq, whose only execution slot is occupied by\nthe blocked cp_down_w itself, so they are pending at most and cancel\nwithout flushing - a reliance on cp_wq being ordered that is now\nnoted next to those cancels (on \n---truncated---","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98069","source_modified_at":"2026-10-19T09:13:18.938Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"0f4b1c7e89e699f588807a914ec6e6396c851a72","lessThan":"7f4f21e4439df30d9aca9fb3bac38191a2f34729","status":"affected","versionType":"git"},{"version":"0f4b1c7e89e699f588807a914ec6e6396c851a72","lessThan":"1f900f585cbb0fbe6aa00c31c9f5bb63ee614456","status":"affected","versionType":"git"},{"version":"0f4b1c7e89e699f588807a914ec6e6396c851a72","lessThan":"32e21bcf4b5b11454bf57c4bb3bf019b71512ace","status":"affected","versionType":"git"},{"version":"0f4b1c7e89e699f588807a914ec6e6396c851a72","lessThan":"2e46248e375a516301884719f08b6015c79a6456","status":"affected","versionType":"git"},{"version":"0f4b1c7e89e699f588807a914ec6e6396c851a72","lessThan":"7febb113795d5de5b690b208f4b0e64a5fad1201","status":"affected","versionType":"git"},{"version":"0f4b1c7e89e699f588807a914ec6e6396c851a72","lessThan":"900e96c9749a06833801f60c393aa1d405ea226c","status":"affected","versionType":"git"},{"version":"0f4b1c7e89e699f588807a914ec6e6396c851a72","lessThan":"1fe627e5db5c3f53a9f9f9c8a66671755d306955","status":"affected","versionType":"git"},{"version":"0f4b1c7e89e699f588807a914ec6e6396c851a72","lessThan":"813f3582ac7ae9f60f917937d54660e0952d5f2d","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98069","source_modified_at":"2026-10-19T09:13:18.938Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"2.6.37","status":"affected"},{"version":"0","lessThan":"2.6.37","status":"unaffected","versionType":"semver"},{"version":"5.10.271","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.111","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.7","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98069","source_modified_at":"2026-10-19T09:13:18.938Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"7f4f21e4439df30d9aca9fb3bac38191a2f34729","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98069","source_modified_at":"2026-10-19T09:13:18.938Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"1f900f585cbb0fbe6aa00c31c9f5bb63ee614456","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98069","source_modified_at":"2026-10-19T09:13:18.938Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"32e21bcf4b5b11454bf57c4bb3bf019b71512ace","basis":"first unaffected version stated in the CVE record"},{"source":"CVE 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List","url":"https://git.kernel.org/stable/c/1fe627e5db5c3f53a9f9f9c8a66671755d306955"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/813f3582ac7ae9f60f917937d54660e0952d5f2d"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:13:18.938Z","content_hash":"19f2cb158f23aa7202e42dc8faad1bf5c39fc48a2c4bbe6c0e489dae70f8e467"}}