Bug 2426091 (CVE-2023-54268)

Summary: CVE-2023-54268 kernel: debugobjects: Don't wake up kswapd from fill_pool()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-12-30 13:08:21 UTC 
In the Linux kernel, the following vulnerability has been resolved:

debugobjects: Don't wake up kswapd from fill_pool()

syzbot is reporting a lockdep warning in fill_pool() because the allocation
from debugobjects is using GFP_ATOMIC, which is (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)
and therefore tries to wake up kswapd, which acquires kswapd_wait::lock.

Since fill_pool() might be called with arbitrary locks held, fill_pool()
should not assume that acquiring kswapd_wait::lock is safe.

Use __GFP_HIGH instead and remove __GFP_NORETRY as it is pointless for
!__GFP_DIRECT_RECLAIM allocation.
Comment 1 Alexander B 2025-12-31 09:58:28 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025123000-CVE-2023-54268-3ba2@gregkh/T