From: MingTao Huang <mintaohuang@tencent.com> mainline inclusion from mainline-v7.1-rc1 commit a1aa9ef47c299c5bbc30594d3c2f0589edf908e6 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/9180 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- When a dev-bound-only BPF program (BPF_F_XDP_DEV_BOUND_ONLY) undergoes JIT compilation with constant blinding enabled (bpf_jit_harden >= 2), bpf_jit_blind_constants() clones the program. The original prog is then freed in bpf_jit_prog_release_other(), which updates aux->prog to point to the surviving clone, but fails to update offload->prog. This leaves offload->prog pointing to the freed original program. When the network namespace is subsequently destroyed, cleanup_net() triggers bpf_dev_bound_netdev_unregister(), which iterates ondev->progs and calls __bpf_prog_offload_destroy(offload->prog). Accessing the freed prog causes a page fault: BUG: unable to handle page fault for address: ffffc900085f1038 Workqueue: netns cleanup_net RIP: 0010:__bpf_prog_offload_destroy+0xc/0x80 Call Trace: __bpf_offload_dev_netdev_unregister+0x257/0x350 bpf_dev_bound_netdev_unregister+0x4a/0x90 unregister_netdevice_many_notify+0x2a2/0x660 ... cleanup_net+0x21a/0x320 The test sequence that triggers this reliably is: 1. Set net.core.bpf_jit_harden=2 (echo 2 > /proc/sys/net/core/bpf_jit_harden) 2. Run xdp_metadata selftest, which creates a dev-bound-only XDP program on a veth inside a netns (./test_progs -t xdp_metadata) 3. cleanup_net -> page fault in __bpf_prog_offload_destroy Dev-bound-only programs are unique in that they have an offload structure but go through the normal JIT path instead of bpf_prog_offload_compile(). This means they are subject to constant blinding's prog clone-and-replace, while also having offload->prog that must stay in sync. Fix this by updating offload->prog in bpf_jit_prog_release_other(), alongside the existing aux->prog update. Both are back-pointers to the prog that must be kept in sync when the prog is replaced. Fixes: 2b3486bc2d23 ("bpf: Introduce device-bound XDP programs") Signed-off-by: MingTao Huang <mintaohuang@tencent.com> Link: https://lore.kernel.org/r/tencent_BCF692F45859CCE6C22B7B0B64827947D406@qq.co... Signed-off-by: Alexei Starovoitov <ast@kernel.org> Conflicts: kernel/bpf/core.c [ctx conflicts] Signed-off-by: Pu Lehui <pulehui@huawei.com> --- kernel/bpf/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index d868824d1293..ff20567bbb78 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1461,6 +1461,8 @@ void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) * know whether fp here is the clone or the original. */ fp->aux->prog = fp; + if (fp->aux->offload) + fp->aux->offload->prog = fp; bpf_prog_clone_free(fp_other); } -- 2.34.1