From: Timo Hunziker <timo.hunziker@xxxxxx> Parse USDT arguments like "8@(%rsp)" on x86. These are emmited by SystemTap. The argument syntax is similar to the existing "memory dereference case" but the offset left out as it's zero (i.e. read the value from the address in the register). We treat it the same as the the "memory dereference case", but set the offset to 0. I've tested that this fixes the "unrecognized arg #N spec: 8@(%rsp).." error I've run into when attaching to a probe with such an argument. Attaching and reading the correct argument values works. Something similar might be needed for the other supported architectures. ref: https://github.com/libbpf/libbpf/issues/559 Signed-off-by: Timo Hunziker <timo.hunziker@xxxxxx> --- Ugh, you're right. Thanks for catching this. I've changed it to USDT_ARG_REG_DEREF and double checked that the values in the arguments are the expected values for my test case. tools/lib/bpf/usdt.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c index b8daae265f99..75b411fc2c77 100644 --- a/tools/lib/bpf/usdt.c +++ b/tools/lib/bpf/usdt.c @@ -1233,6 +1233,14 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec if (reg_off < 0) return reg_off; arg->reg_off = reg_off; + } else if (sscanf(arg_str, " %d @ ( %%%15[^)] ) %n", &arg_sz, reg_name, &len) == 2) { + /* Memory dereference case without offset, e.g., 8@(%rsp) */ + arg->arg_type = USDT_ARG_REG_DEREF; + arg->val_off = 0; + reg_off = calc_pt_regs_off(reg_name); + if (reg_off < 0) + return reg_off; + arg->reg_off = reg_off; } else if (sscanf(arg_str, " %d @ %%%15s %n", &arg_sz, reg_name, &len) == 2) { /* Register read case, e.g., -4@%eax */ arg->arg_type = USDT_ARG_REG; -- 2.36.2 _________________________________________________________________ ________________________________________________________ Your E-Mail. Your Cloud. Your Office. eclipso Mail & Cloud. https://www.eclipso.de
