CVE-2023-52446 — bpf: Fix a race condition between btf_put() and map_free()

2026-10-02T08:45:33.480019+00:00

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix a race condition between btf_put() and map_free()

When running `./test_progs -j` in my local vm with latest kernel, I once hit a kasan error like below:

[ 1887.184724] BUG: KASAN: slab-use-after-free in bpf_rb_root_free+0x1f8/0x2b0 [ 1887.185599] Read of size 4 at addr ffff888106806910 by task kworker/u12:2/2830 [ 1887.186498] [ 1887.186712] CPU: 3 PID: 2830 Comm: kworker/u12:2 Tainted: G OEL 6.7.0-rc3-00699-g90679706d486-dirty #494 [ 1887.188034] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 1887.189618] Workqueue: events_unbound bpf_map_free_deferred [ 1887.190341] Call Trace: [ 1887.190666] [ 1887.190949] dump_stack_lvl+0xac/0xe0 [ 1887.191423] ? nf_tcp_handle_invalid+0x1b0/0x1b0 [ 1887.192019] ? panic+0x3c0/0x3c0 [ 1887.192449] print_report+0x14f/0x720 [ 1887.192930] ? preempt_count_sub+0x1c/0xd0 [ 1887.193459] ? __virt_addr_valid+0xac/0x120 [ 1887.194004] ? bpf_rb_root_free+0x1f8/0x2b0 [ 1887.194572] kasan_report+0xc3/0x100 [ 1887.195085] ? bpf_rb_root_free+0x1f8/0x2b0 [ 1887.195668] bpf_rb_root_free+0x1f8/0x2b0 [ 1887.196183] ? __bpf_obj_drop_impl+0xb0/0xb0 [ 1887.196736] ? preempt_count_sub+0x1c/0xd0 [ 1887.197270] ? preempt_count_sub+0x1c/0xd0 [ 1887.197802] ? _raw_spin_unlock+0x1f/0x40 [ 1887.198319] bpf_obj_free_fields+0x1d4/0x260 […

Most recent entries from all

CVE-2023-52446 — bpf: Fix a race condition between btf_put() and map_free()