CVSS3
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
5.1%
In the Linux kernel, the following vulnerability has been resolved: sched/fair: Fix fault in reweight_entity Syzbot found a GPF in reweight_entity. This has been bisected to commit 4ef0c5c6b5ba (βkernel/sched: Fix sched_fork() access an invalid sched_task_groupβ) ThereΒ is a race between sched_post_fork() and setpriority(PRIO_PGRP) within a thread group that causes a null-ptr-derefΒ in reweight_entity() in CFS. The scenario is that the main process spawns number of new threads, which then call setpriority(PRIO_PGRP, 0, -20), wait, and exit. For each of the new threads the copy_process() gets invoked, which adds the new task_struct and calls sched_post_fork() for it. In the above scenario there is a possibility that setpriority(PRIO_PGRP) and set_one_prio() will be called for a thread in the group that is just being created by copy_process(), and for which the sched_post_fork() has not been executed yet. This will trigger a null pointer dereference in reweight_entity(),Β as it will try to access the run queue pointer, which hasnβt been set. Before the mentioned change the cfs_rq pointer for the task has been set in sched_fork(), which is called much earlier in copy_process(), before the new task is added to the thread_group. Now it is done in the sched_post_fork(), which is called after that. To fix the issue the remove the update_load param from the update_load param() function and call reweight_task() only if the task flag doesnβt have the TASK_NEW flag set.
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
Debian | 12 | all | linux | <Β 5.16.14-1 | linux_5.16.14-1_all.deb |
Debian | 11 | all | linux | <Β 5.10.140-1 | linux_5.10.140-1_all.deb |
Debian | 999 | all | linux | <Β 5.16.14-1 | linux_5.16.14-1_all.deb |
Debian | 13 | all | linux | <Β 5.16.14-1 | linux_5.16.14-1_all.deb |
CVSS3
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
5.1%