bpf, x86: fix freeing of not-finalized bpf_prog_pack

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf, x86: fix freeing of not-finalized bpf_prog_pack syzbot reported a few issues with bpf_prog_pack [1], [2]. This only happens with multiple subprogs. In jit_subprogs(), we first call bpf_int_jit_compile() on each sub program. And then, we call it on each sub program again. jit_data is not freed in the first call of bpf_int_jit_compile(). Similarly we don't call bpf_jit_binary_pack_finalize() in the first call of bpf_int_jit_compile(). If bpf_int_jit_compile() failed for one sub program, we will call bpf_jit_binary_pack_finalize() for this sub program. However, we don't have a chance to call it for other sub programs. Then we will hit "goto out_free" in jit_subprogs(), and call bpf_jit_free on some subprograms that haven't got bpf_jit_binary_pack_finalize() yet. At this point, bpf_jit_binary_pack_free() is called and the whole 2MB page is freed erroneously. Fix this with a custom bpf_jit_free() for x86_64, which calls bpf_jit_binary_pack_finalize() if necessary. Also, with custom bpf_jit_free(), bpf_prog_aux->use_bpf_prog_pack is not needed any more, remove it. [1] https://syzkaller.appspot.com/bug?extid=2f649ec6d2eea1495a8f [2] https://syzkaller.appspot.com/bug?extid=87f65c75f4a72db05445

Timeline

1. Jun 18, 2025, 11:03 AM UTCCVE published
2. Oct 15, 2026, 9:30 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 15, 2026, 9:31 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 1022a5498f6f745c3b5fd3f050a5e11e7ca354f0 · fixed in f91ce608a79c0db3e72bd63c23e011a9ebc31505; From 1022a5498f6f745c3b5fd3f050a5e11e7ca354f0 · fixed in 60e66074812dde9cde3d99cdd3caa9e40f1a4516; From 1022a5498f6f745c3b5fd3f050a5e11e7ca354f0 · fixed in 1d5f82d9dd477d5c66e0214a68c3e4f308eadd6d

• Linux Linux

  5.18

• KernelLinux

  From 5.18.0 · fixed in 5.18.18; From 5.19.0 · fixed in 5.19.2

References 3