{"id":"CVE-2026-90081","summary":"net/rds: use wq_has_sleeper() in rds_cong_map_updated()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: use wq_has_sleeper() in rds_cong_map_updated()\n\nrds_cong_map_updated() runs after a peer's congestion map has been\nrewritten (by rds_tcp_cong_recv() and rds_ib_cong_recv(), or the\nclear-all in the loopback and IB send-completion paths).  It bumps\nrds_cong_generation and then checks waitqueue_active() on\nmap-\u003em_waitq and on rds_poll_waitq to decide whether anyone needs\nwaking.  atomic_inc() carries no ordering and waitqueue_active() is a\nplain load, so nothing orders the map and generation stores before\nthe wait queue reads.  The waiters do the mirror image: rds_cong_wait()\nadds itself to m_waitq and then tests the port bit, and rds_poll()\nregisters on rds_poll_waitq and then reads the generation.  That is\nthe store-buffering pattern described above waitqueue_active() in\ninclude/linux/wait.h - the updater can observe an empty wait queue\nwhile the waiter still observes the port as congested, and no wake-up\nis issued.\n\nrds_cong_wait() is an interruptible sleep with no timeout, so a\nsender blocked on a congested port stays blocked until the next\ncongestion update from that peer arrives or a signal is delivered.\nA poll() waiter misses the map-updated notification the same way.\n\nUse wq_has_sleeper(), which is waitqueue_active() preceded by the\nrequired full barrier, as rds_tcp_state_change() already does for\nthe same pattern.","modified":"2026-09-19T03:47:23.993573623Z","published":"2026-09-17T16:05:58.866Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90081.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0e169f6a2adeb17b5577ed7e8abd642465bb50ec"},{"type":"WEB","url":"https://git.kernel.org/stable/c/281f9fda2e06d6c211bb365a5379ed2e05cc2e21"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2a809d7896dbf18e1ecfbdd930f71c9fc298b16d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/42884bd8b8fd023d6a610a695bd5ddd1d5dece17"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a526214b9f0548ca0e53a6e0d1727d8ea9befc23"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bf2b8130723efcb5b86c3ddb6317c3a9b2a9cfc5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d4f484661961636eb90d287050959e613795f73a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fa4b98e891fda28cc0638d809c6125ec63d8319d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90081.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90081"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"922cb17a5c812fcc9ebee249f4109db099896941"},{"fixed":"2a809d7896dbf18e1ecfbdd930f71c9fc298b16d"},{"fixed":"fa4b98e891fda28cc0638d809c6125ec63d8319d"},{"fixed":"0e169f6a2adeb17b5577ed7e8abd642465bb50ec"},{"fixed":"42884bd8b8fd023d6a610a695bd5ddd1d5dece17"},{"fixed":"a526214b9f0548ca0e53a6e0d1727d8ea9befc23"},{"fixed":"bf2b8130723efcb5b86c3ddb6317c3a9b2a9cfc5"},{"fixed":"281f9fda2e06d6c211bb365a5379ed2e05cc2e21"},{"fixed":"d4f484661961636eb90d287050959e613795f73a"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90081.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.30"},{"fixed":"5.10.270"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.221"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.188"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.157"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.110"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.52"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90081.json"}}],"schema_version":"1.9.0"}