Bug 2334485 (CVE-2024-56583)

Summary: CVE-2024-56583 kernel: sched/deadline: Fix warning in migrate_enable for boosted tasks
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: low    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2024-12-27 15:05:07 UTC
In the Linux kernel, the following vulnerability has been resolved:

sched/deadline: Fix warning in migrate_enable for boosted tasks

When running the following command:

while true; do
    stress-ng --cyclic 30 --timeout 30s --minimize --quiet
done

a warning is eventually triggered:

WARNING: CPU: 43 PID: 2848 at kernel/sched/deadline.c:794
setup_new_dl_entity+0x13e/0x180
...
Call Trace:
 <TASK>
 ? show_trace_log_lvl+0x1c4/0x2df
 ? enqueue_dl_entity+0x631/0x6e0
 ? setup_new_dl_entity+0x13e/0x180
 ? __warn+0x7e/0xd0
 ? report_bug+0x11a/0x1a0
 ? handle_bug+0x3c/0x70
 ? exc_invalid_op+0x14/0x70
 ? asm_exc_invalid_op+0x16/0x20
 enqueue_dl_entity+0x631/0x6e0
 enqueue_task_dl+0x7d/0x120
 __do_set_cpus_allowed+0xe3/0x280
 __set_cpus_allowed_ptr_locked+0x140/0x1d0
 __set_cpus_allowed_ptr+0x54/0xa0
 migrate_enable+0x7e/0x150
 rt_spin_unlock+0x1c/0x90
 group_send_sig_info+0xf7/0x1a0
 ? kill_pid_info+0x1f/0x1d0
 kill_pid_info+0x78/0x1d0
 kill_proc_info+0x5b/0x110
 __x64_sys_kill+0x93/0xc0
 do_syscall_64+0x5c/0xf0
 entry_SYSCALL_64_after_hwframe+0x6e/0x76
 RIP: 0033:0x7f0dab31f92b

This warning occurs because set_cpus_allowed dequeues and enqueues tasks
with the ENQUEUE_RESTORE flag set. If the task is boosted, the warning
is triggered. A boosted task already had its parameters set by
rt_mutex_setprio, and a new call to setup_new_dl_entity is unnecessary,
hence the WARN_ON call.

Check if we are requeueing a boosted task and avoid calling
setup_new_dl_entity if that's the case.

Comment 1 Avinash Hanwate 2024-12-28 06:09:30 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024122754-CVE-2024-56583-b1dc@gregkh/T