{"id":"CVE-2022-49443","summary":"list: fix a data-race around ep-\u003erdllist","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nlist: fix a data-race around ep-\u003erdllist\n\nep_poll() first calls ep_events_available() with no lock held and checks\nif ep-\u003erdllist is empty by list_empty_careful(), which reads\nrdllist-\u003eprev.  Thus all accesses to it need some protection to avoid\nstore/load-tearing.\n\nNote INIT_LIST_HEAD_RCU() already has the annotation for both prev\nand next.\n\nCommit bf3b9f6372c4 (\"epoll: Add busy poll support to epoll with socket\nfds.\") added the first lockless ep_events_available(), and commit\nc5a282e9635e (\"fs/epoll: reduce the scope of wq lock in epoll_wait()\")\nmade some ep_events_available() calls lockless and added single call under\na lock, finally commit e59d3c64cba6 (\"epoll: eliminate unnecessary lock\nfor zero timeout\") made the last ep_events_available() lockless.\n\nBUG: KCSAN: data-race in do_epoll_wait / do_epoll_wait\n\nwrite to 0xffff88810480c7d8 of 8 bytes by task 1802 on cpu 0:\n INIT_LIST_HEAD include/linux/list.h:38 [inline]\n list_splice_init include/linux/list.h:492 [inline]\n ep_start_scan fs/eventpoll.c:622 [inline]\n ep_send_events fs/eventpoll.c:1656 [inline]\n ep_poll fs/eventpoll.c:1806 [inline]\n do_epoll_wait+0x4eb/0xf40 fs/eventpoll.c:2234\n do_epoll_pwait fs/eventpoll.c:2268 [inline]\n __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline]\n __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275\n __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nread to 0xffff88810480c7d8 of 8 bytes by task 1799 on cpu 1:\n list_empty_careful include/linux/list.h:329 [inline]\n ep_events_available fs/eventpoll.c:381 [inline]\n ep_poll fs/eventpoll.c:1797 [inline]\n do_epoll_wait+0x279/0xf40 fs/eventpoll.c:2234\n do_epoll_pwait fs/eventpoll.c:2268 [inline]\n __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline]\n __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275\n __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nvalue changed: 0xffff88810480c7d0 -\u003e 0xffff888103c15098\n\nReported by Kernel Concurrency Sanitizer on:\nCPU: 1 PID: 1799 Comm: syz-fuzzer Tainted: G        W         5.17.0-rc7-syzkaller-dirty #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011","modified":"2026-04-11T12:44:03.481221Z","published":"2025-02-26T02:12:55.959Z","related":["ALSA-2025:20518","SUSE-SU-2025:1027-1","SUSE-SU-2025:1176-1","SUSE-SU-2025:1183-1","SUSE-SU-2025:1241-1","SUSE-SU-2025:1293-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49443.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5d5d993f16be15d124be7b8ec71b28ef7b7dc3af"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cb3e48f7a35033deb9455abe3932e63cb500b9eb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d679ae94fdd5d3ab00c35078f5af5f37e068b03d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e039c0b5985999b150594126225e1ee51df7b4c9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49443.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-49443"},{"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":"bf3b9f6372c45b0fbf24d86b8794910d20170017"},{"fixed":"5d5d993f16be15d124be7b8ec71b28ef7b7dc3af"},{"fixed":"cb3e48f7a35033deb9455abe3932e63cb500b9eb"},{"fixed":"e039c0b5985999b150594126225e1ee51df7b4c9"},{"fixed":"d679ae94fdd5d3ab00c35078f5af5f37e068b03d"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-49443.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.12.0"},{"fixed":"5.15.46"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"5.17.14"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.18.0"},{"fixed":"5.18.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-49443.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}