UBUNTU-CVE-2026-93173: Medium severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: bpf,lsm: Drop bpfprogfree from sleepablelsmhooks bpfprogputrcu() is the callrcu() callback for non-sleepable programs. securitybpfprogfree() called from there fires bpfprogfree in softirq; if a sleepable LSM prog is attached to that hook, mightfault() BUGs: BUG: sleeping function called from invalid context inatomic(): 1, irqsdisabled(): 0, nonblock: 0, pid: 5038 preemptcount: 101, expected: 0 Call Trace: <IRQ> bpfprogentersleepable+0x1cd/0x320 kernel/bpf/trampoline.c:1255 bpftrampoline6442549705+0x53/0xd7 securitybpfprogfree+0xde/0x130 security/security.c:5465 bpfprogputrcu+0xab/0xd0 kernel/bpf/syscall.c:2365 rcudobatch kernel/rcu/tree.c:2617 [inline] handlesoftirqs+0x236/0x800 kernel/softirq.c:622 </IRQ> The callrcu/callrcutaskstrace split reflects the freed program's sleepability, not that of any attached observer. securitybpfprogfree() also frees prog->aux->security, which has to stay after the grace period, so drop bpfprogfree from sleepablelsmhooks rather than move the call. Non-sleepable observers still run there.