From: Pu Lehui <pulehui@huawei.com> mainline inclusion from mainline-v6.8-rc2 commit 1732ebc4a26181c8f116c7639db99754b313edc8 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8335 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------------------------------------- We encountered a kernel crash triggered by the bpf_tcp_ca testcase as show below: Unable to handle kernel paging request at virtual address ff60000088554500 Oops [#1] ... CPU: 3 PID: 458 Comm: test_progs Tainted: G OE 6.8.0-rc1-kselftest_plain #1 Hardware name: riscv-virtio,qemu (DT) epc : 0xff60000088554500 ra : tcp_ack+0x288/0x1232 epc : ff60000088554500 ra : ffffffff80cc7166 sp : ff2000000117ba50 gp : ffffffff82587b60 tp : ff60000087be0040 t0 : ff60000088554500 t1 : ffffffff801ed24e t2 : 0000000000000000 s0 : ff2000000117bbc0 s1 : 0000000000000500 a0 : ff20000000691000 a1 : 0000000000000018 a2 : 0000000000000001 a3 : ff60000087be03a0 a4 : 0000000000000000 a5 : 0000000000000000 a6 : 0000000000000021 a7 : ffffffff8263f880 s2 : 000000004ac3c13b s3 : 000000004ac3c13a s4 : 0000000000008200 s5 : 0000000000000001 s6 : 0000000000000104 s7 : ff2000000117bb00 s8 : ff600000885544c0 s9 : 0000000000000000 s10: ff60000086ff0b80 s11: 000055557983a9c0 t3 : 0000000000000000 t4 : 000000000000ffc4 t5 : ffffffff8154f170 t6 : 0000000000000030 status: 0000000200000120 badaddr: ff60000088554500 cause: 000000000000000c Code: c796 67d7 0000 0000 0052 0002 c13b 4ac3 0000 0000 (0001) 0000 ---[ end trace 0000000000000000 ]--- The reason is that commit 2cd3e3772e41 ("x86/cfi,bpf: Fix bpf_struct_ops CFI") changes the func_addr of arch_prepare_bpf_trampoline in struct_ops from NULL to non-NULL, while we use func_addr on RV64 to differentiate between struct_ops and regular trampoline. When the struct_ops testcase is triggered, it emits wrong prologue and epilogue, and lead to unpredictable issues. After commit 2cd3e3772e41, we can use BPF_TRAMP_F_INDIRECT to distinguish them as it always be set in struct_ops. Fixes: 2cd3e3772e41 ("x86/cfi,bpf: Fix bpf_struct_ops CFI") Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Björn Töpel <bjorn@rivosinc.com> Acked-by: Björn Töpel <bjorn@kernel.org> Link: https://lore.kernel.org/bpf/20240123023207.1917284-1-pulehui@huaweicloud.com Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- arch/riscv/net/bpf_jit_comp64.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 4a1a61ae14d6..4ae7e6e7c061 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -796,6 +796,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY]; struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT]; struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN]; + bool is_struct_ops = flags & BPF_TRAMP_F_INDIRECT; void *orig_call = func_addr; bool save_ret; u32 insn; @@ -878,7 +879,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, stack_size = round_up(stack_size, 16); - if (func_addr) { + if (!is_struct_ops) { /* For the trampoline called from function entry, * the frame of traced function and the frame of * trampoline need to be considered. @@ -998,7 +999,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, emit_ld(RV_REG_S1, -sreg_off, RV_REG_FP, ctx); - if (func_addr) { + if (!is_struct_ops) { /* trampoline called from function entry */ emit_ld(RV_REG_T0, stack_size - 8, RV_REG_SP, ctx); emit_ld(RV_REG_FP, stack_size - 16, RV_REG_SP, ctx); -- 2.34.1