cbcvebase.
CVE-2022-49443
published 2025-02-26

CVE-2022-49443: In the Linux kernel, the following vulnerability has been resolved: list: fix a data-race around ep->rdllist ep_poll() first calls ep_events_available() with…

PriorityP417medium4.7CVSS 3.1
AVLACHPRLUINSUCNINAH
EPSS
0.18%
7.4th percentile
In the Linux kernel, the following vulnerability has been resolved: list: fix a data-race around ep->rdllist ep_poll() first calls ep_events_available() with no lock held and checks if ep->rdllist is empty by list_empty_careful(), which reads rdllist->prev. Thus all accesses to it need some protection to avoid store/load-tearing. Note INIT_LIST_HEAD_RCU() already has the annotation for both prev and next. Commit bf3b9f6372c4 ("epoll: Add busy poll support to epoll with socket fds.") added the first lockless ep_events_available(), and commit c5a282e9635e ("fs/epoll: reduce the scope of wq lock in epoll_wait()") made some ep_events_available() calls lockless and added single call under a lock, finally commit e59d3c64cba6 ("epoll: eliminate unnecessary lock for zero timeout") made the last ep_events_available() lockless. BUG: KCSAN: data-race in do_epoll_wait / do_epoll_wait write to 0xffff88810480c7d8 of 8 bytes by task 1802 on cpu 0: INIT_LIST_HEAD include/linux/list.h:38 [inline] list_splice_init include/linux/list.h:492 [inline] ep_start_scan fs/eventpoll.c:622 [inline] ep_send_events fs/eventpoll.c:1656 [inline] ep_poll fs/eventpoll.c:1806 [inline] do_epoll_wait+0x4eb/0xf40 fs/eventpoll.c:2234 do_epoll_pwait fs/eventpoll.c:2268 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline] __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll.c:2275 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88810480c7d8 of 8 bytes by task 1799 on cpu 1: list_empty_careful include/linux/list.h:329 [inline] ep_events_available fs/eventpoll.c:381 [inline] ep_poll fs/eventpoll.c:1797 [inline] do_epoll_wait+0x279/0xf40 fs/eventpoll.c:2234 do_epoll_pwait fs/eventpoll.c:2268 [inline] __do_sys_epoll_pwait fs/eventpoll.c:2281 [inline] __se_sys_epoll_pwait+0x12b/0x240 fs/eventpoll.c:2275 __x64_sys_epoll_pwait+0x74/0x80 fs/eventpoll

Affected

12 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.18.5-1 (bookworm)linux 5.18.5-1 (bookworm)
linuxlinux
linuxlinux>= bf3b9f6372c45b0fbf24d86b8794910d20170017 < 5d5d993f16be15d124be7b8ec71b28ef7b7dc3af5d5d993f16be15d124be7b8ec71b28ef7b7dc3af
linuxlinux>= bf3b9f6372c45b0fbf24d86b8794910d20170017 < cb3e48f7a35033deb9455abe3932e63cb500b9ebcb3e48f7a35033deb9455abe3932e63cb500b9eb
linuxlinux>= bf3b9f6372c45b0fbf24d86b8794910d20170017 < e039c0b5985999b150594126225e1ee51df7b4c9e039c0b5985999b150594126225e1ee51df7b4c9
linuxlinux>= bf3b9f6372c45b0fbf24d86b8794910d20170017 < d679ae94fdd5d3ab00c35078f5af5f37e068b03dd679ae94fdd5d3ab00c35078f5af5f37e068b03d
linuxlinux_kernel>= 0 < 5.18.5-15.18.5-1
linuxlinux_kernel>= 0 < 5.18.5-15.18.5-1
linuxlinux_kernel>= 0 < 5.18.5-15.18.5-1
linuxlinux_kernel>= 4.12 < 5.15.465.15.46
linuxlinux_kernel>= 5.16 < 5.17.145.17.14
linuxlinux_kernel>= 5.18 < 5.18.35.18.3

CVSS provenance

nvdv3.14.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
osv4.7MEDIUM
vendor_debian4.7MEDIUM
vendor_redhat4.7MEDIUM
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