Bug 2334795 (CVE-2024-56709)

Summary: CVE-2024-56709 kernel: io_uring: check if iowq is killed before queuing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2024-12-29 09:01:34 UTC 
In the Linux kernel, the following vulnerability has been resolved:

io_uring: check if iowq is killed before queuing

task work can be executed after the task has gone through io_uring
termination, whether it's the final task_work run or the fallback path.
In this case, task work will find ->io_wq being already killed and
null'ed, which is a problem if it then tries to forward the request to
io_queue_iowq(). Make io_queue_iowq() fail requests in this case.

Note that it also checks PF_KTHREAD, because the user can first close
a DEFER_TASKRUN ring and shortly after kill the task, in which case
->iowq check would race.
Comment 1 Avinash Hanwate 2024-12-29 10:13:57 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024122918-CVE-2024-56709-655c@gregkh/T
Comment 2 errata-xmlrpc 2025-11-11 10:24:25 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:20518 https://access.redhat.com/errata/RHSA-2025:20518