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Test your applicationsThere is no fixed version for Centos:9
kernel-debug-modules-core
.
Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules-core
package and not the kernel-debug-modules-core
package as distributed by Centos
.
See How to fix?
for Centos:9
relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix deadlock when freeing cgroup storage
The following commit bc235cdb423a ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]") first introduced deadlock prevention for fentry/fexit programs attaching on bpf_task_storage helpers. That commit also employed the logic in map free path in its v6 version.
Later bpf_cgrp_storage was first introduced in c4bcfb38a95e ("bpf: Implement cgroup storage available to non-cgroup-attached bpf progs") which faces the same issue as bpf_task_storage, instead of its busy counter, NULL was passed to bpf_local_storage_map_free() which opened a window to cause deadlock:
<TASK>
(acquiring local_storage->lock)
_raw_spin_lock_irqsave+0x3d/0x50
bpf_local_storage_update+0xd1/0x460
bpf_cgrp_storage_get+0x109/0x130
bpf_prog_a4d4a370ba857314_cgrp_ptr+0x139/0x170
? __bpf_prog_enter_recur+0x16/0x80
bpf_trampoline_6442485186+0x43/0xa4
cgroup_storage_ptr+0x9/0x20
(holding local_storage->lock)
bpf_selem_unlink_storage_nolock.constprop.0+0x135/0x160
bpf_selem_unlink_storage+0x6f/0x110
bpf_local_storage_map_free+0xa2/0x110
bpf_map_free_deferred+0x5b/0x90
process_one_work+0x17c/0x390
worker_thread+0x251/0x360
kthread+0xd2/0x100
ret_from_fork+0x34/0x50
ret_from_fork_asm+0x1a/0x30
</TASK>
Progs:
Steps to reproduce:
Fix this issue by passing its busy counter to the free procedure so it can be properly incremented before storage/smap locking.