diff options
| author | Menglong Dong <menglong8.dong@gmail.com> | 2025-12-19 22:29:48 +0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-01-06 11:40:48 -0800 |
| commit | 8f3e00af8e52c0d2d8e0e15154d28ec7d639d4d9 (patch) | |
| tree | df65ce02991c374cd7fe5d1085b8deef295c71f8 | |
| parent | f0b9d8eb98dfee8d00419aa07543bdc2c1a44fb1 (diff) | |
riscv, bpf: Fix incorrect usage of BPF_TRAMP_F_ORIG_STACK
The usage of BPF_TRAMP_F_ORIG_STACK in __arch_prepare_bpf_trampoline() is
wrong, and it should be BPF_TRAMP_F_CALL_ORIG, which caused crash as
Andreas reported:
Insufficient stack space to handle exception!
Task stack: [0xff20000000010000..0xff20000000014000]
Overflow stack: [0xff600000ffdad070..0xff600000ffdae070]
CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary)
Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025
epc : copy_from_kernel_nofault+0xa/0x198
ra : bpf_probe_read_kernel+0x20/0x60
epc : ffffffff802b732a ra : ffffffff801e6070 sp : ff2000000000ffe0
gp : ffffffff82262ed0 tp : 0000000000000000 t0 : ffffffff80022320
t1 : ffffffff801e6056 t2 : 0000000000000000 s0 : ff20000000010040
s1 : 0000000000000008 a0 : ff20000000010050 a1 : ff60000083b3d320
a2 : 0000000000000008 a3 : 0000000000000097 a4 : 0000000000000000
a5 : 0000000000000000 a6 : 0000000000000021 a7 : 0000000000000003
s2 : ff20000000010050 s3 : ff6000008459fc18 s4 : ff60000083b3d340
s5 : ff20000000010060 s6 : 0000000000000000 s7 : ff20000000013aa8
s8 : 0000000000000000 s9 : 0000000000008000 s10: 000000000058dcb0
s11: 000000000058dca7 t3 : 000000006925116d t4 : ff6000008090f026
t5 : 00007fff9b0cbaa8 t6 : 0000000000000016
status: 0000000200000120 badaddr: 0000000000000000 cause: 8000000000000005
Kernel panic - not syncing: Kernel stack overflow
CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary)
Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025
Call Trace:
[<ffffffff8001a1f8>] dump_backtrace+0x28/0x38
[<ffffffff80002502>] show_stack+0x3a/0x50
[<ffffffff800122be>] dump_stack_lvl+0x56/0x80
[<ffffffff80012300>] dump_stack+0x18/0x22
[<ffffffff80002abe>] vpanic+0xf6/0x328
[<ffffffff80002d2e>] panic+0x3e/0x40
[<ffffffff80019ef0>] handle_bad_stack+0x98/0xa0
[<ffffffff801e6070>] bpf_probe_read_kernel+0x20/0x60
Just fix it.
Fixes: 47c9214dcbea ("bpf: fix the usage of BPF_TRAMP_F_SKIP_FRAME")
Link: https://lore.kernel.org/bpf/20251219142948.204312-1-dongml2@chinatelecom.cn
Closes: https://lore.kernel.org/bpf/874ipnkfvt.fsf@igel.home/
Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | arch/riscv/net/bpf_jit_comp64.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 5f9457e910e8..37888abee70c 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -1133,10 +1133,6 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, store_args(nr_arg_slots, args_off, ctx); - /* skip to actual body of traced function */ - if (flags & BPF_TRAMP_F_ORIG_STACK) - orig_call += RV_FENTRY_NINSNS * 4; - if (flags & BPF_TRAMP_F_CALL_ORIG) { emit_imm(RV_REG_A0, ctx->insns ? (const s64)im : RV_MAX_COUNT_IMM, ctx); ret = emit_call((const u64)__bpf_tramp_enter, true, ctx); @@ -1171,6 +1167,8 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, } if (flags & BPF_TRAMP_F_CALL_ORIG) { + /* skip to actual body of traced function */ + orig_call += RV_FENTRY_NINSNS * 4; restore_args(min_t(int, nr_arg_slots, RV_MAX_REG_ARGS), args_off, ctx); restore_stack_args(nr_arg_slots - RV_MAX_REG_ARGS, args_off, stk_arg_off, ctx); ret = emit_call((const u64)orig_call, true, ctx); |