Bug 2541201 (CVE-2026-98058)

Summary: CVE-2026-98058 kernel: bpf: Mark syscall helpers as sleepable
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) subsystem. Certain internal helper functions that pause execution to perform blocking operations were not properly marked as sleepable. A local user with permissions to load BPF programs can invoke these functions within non-sleepable timer callbacks. This action triggers an invalid scheduling state, leading to a kernel crash and resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-09-25 11:00:12 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Mark syscall helpers as sleepable

bpf_sys_bpf() executes the bpf(2) syscall body, which can take mutexes,
allocate with GFP_KERNEL, and wait for an RCU grace period.
bpf_sys_close() reaches close_fd() and filp_close(), which can sleep as
well.

Both helpers are limited to BPF_PROG_TYPE_SYSCALL, whose main program is
sleepable. That does not make every callback sleepable: a syscall program
can register a bpf_timer callback, and the verifier checks that callback
in a non-sleepable context while retaining the syscall helper set.

Without .might_sleep on the prototypes, such a callback can invoke
bpf_sys_bpf() from hrtimer softirq context and trigger a
scheduling-while-atomic failure. bpf_sys_close() is exposed through the
same missing context check.

Set .might_sleep on both prototypes so the existing helper-context check
rejects them from timer callbacks and other atomic regions. Calls from the
sleepable main body remain valid.
Comment 1 Keith Grant 2026-09-28 23:55:59 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98058.mbox