cbcvebase.
CVE-2025-21771
published 2025-02-27

CVE-2025-21771: In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix incorrect autogroup migration detection scx_move_task() is called from…

PriorityP420medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.20%
10.2th percentile
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix incorrect autogroup migration detection scx_move_task() is called from sched_move_task() and tells the BPF scheduler that cgroup migration is being committed. sched_move_task() is used by both cgroup and autogroup migrations and scx_move_task() tried to filter out autogroup migrations by testing the destination cgroup and PF_EXITING but this is not enough. In fact, without explicitly tagging the thread which is doing the cgroup migration, there is no good way to tell apart scx_move_task() invocations for racing migration to the root cgroup and an autogroup migration. This led to scx_move_task() incorrectly ignoring a migration from non-root cgroup to an autogroup of the root cgroup triggering the following warning: WARNING: CPU: 7 PID: 1 at kernel/sched/ext.c:3725 scx_cgroup_can_attach+0x196/0x340 ... Call Trace: cgroup_migrate_execute+0x5b1/0x700 cgroup_attach_task+0x296/0x400 __cgroup_procs_write+0x128/0x140 cgroup_procs_write+0x17/0x30 kernfs_fop_write_iter+0x141/0x1f0 vfs_write+0x31d/0x4a0 __x64_sys_write+0x72/0xf0 do_syscall_64+0x82/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e Fix it by adding an argument to sched_move_task() that indicates whether the moving is for a cgroup or autogroup migration. After the change, scx_move_task() is called only for cgroup migrations and renamed to scx_cgroup_move_task().

Affected

10 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.16-1 (forky)linux 6.12.16-1 (forky)
linuxlinux——
linuxlinux>= 8195136669661fdfe54e9a8923c33b31c92fc1da < 75bf2f80c046d2ec5a07455891ea0a9fb6d8b5f675bf2f80c046d2ec5a07455891ea0a9fb6d8b5f6
linuxlinux>= 8195136669661fdfe54e9a8923c33b31c92fc1da < d8b510d0ddc65d8a71e0f9a3acc9ed5f010fc514d8b510d0ddc65d8a71e0f9a3acc9ed5f010fc514
linuxlinux>= 8195136669661fdfe54e9a8923c33b31c92fc1da < d6f3e7d564b2309e1f17e709a70eca78d7ca2bb8d6f3e7d564b2309e1f17e709a70eca78d7ca2bb8
linuxlinux_kernel——
linuxlinux_kernel>= 0 < 6.12.16-16.12.16-1
linuxlinux_kernel>= 0 < 6.12.16-16.12.16-1
linuxlinux_kernel>= 6.12 < 6.12.166.12.16
linuxlinux_kernel>= 6.13 < 6.13.46.13.4

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5LOW
vendor_redhat5.5MEDIUM
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