@@ -50,6 +50,7 @@ Synopsis of fprobe-events
   $argN         : Fetch the Nth function argument. (N >= 1) (\*2)
   $retval       : Fetch return value.(\*3)
   $comm         : Fetch current task comm.
+  $current      : Fetch the address of the current task_struct.
   +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*4)(\*5)
   \IMM          : Store an immediate value to the argument.
   NAME=FETCHARG : Set NAME as the argument name of FETCHARG.

@@ -53,6 +53,7 @@ Synopsis of kprobe_events
   $argN		: Fetch the Nth function argument. (N >= 1) (\*1)
   $retval	: Fetch return value.(\*2)
   $comm		: Fetch current task comm.
+  $current      : Fetch the address of the current task_struct.
   +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*3)(\*4)
   \IMM		: Store an immediate value to the argument.
   NAME=FETCHARG : Set NAME as the argument name of FETCHARG.

@@ -4323,13 +4323,13 @@ static const char readme_msg[] =
 	"\t     args: <name>=fetcharg[:type]\n"
 	"\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
-	"\t           $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
+	"\t           $stack<index>, $stack, $retval, $comm, $arg<N>, $current\n"
 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
 	"\t           [(structname[,field])]<argname>[->field[->field|.field...]],\n"
 	"\t           [(structname[,field])](fetcharg)->field[->field|.field...],\n"
 #endif
 #else
-	"\t           $stack<index>, $stack, $retval, $comm,\n"
+	"\t           $stack<index>, $stack, $retval, $comm, $current\n"
 #endif
 	"\t           +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
 	"\t     kernel return probes support: $retval, $arg<N>, $comm\n"

@@ -730,6 +730,24 @@ static int parse_btf_arg(char *varname,
 		goto found;
 	}
 
+	if (strcmp(varname, "$current") == 0) {
+		code->op = FETCH_OP_CURRENT;
+		/* If no typecast is specified for $current, use task_struct by default */
+		if (!ctx->struct_btf) {
+			s32 ttid = bpf_find_btf_id("task_struct", BTF_KIND_STRUCT,
+						   &ctx->struct_btf);
+
+			if (ttid < 0) {
+				trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
+				return -ENOENT;
+			}
+			/* btf_type_skip_modifier() requires u32 for type id. */
+			tid = ttid;
+			ctx->last_struct = btf_type_skip_modifiers(ctx->struct_btf, tid, &tid);
+		}
+		goto found;
+	}
+
 	if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
 		code->op = FETCH_OP_RETVAL;
 		/* Check whether the function return type is not void, even with typecast. */

@@ -763,8 +781,8 @@ static int parse_btf_arg(char *varname,
 			return -ENOENT;
 		}
 	}
-	params = ctx->params;
 
+	params = ctx->params;
 	for (i = 0; i < ctx->nr_params; i++) {
 		const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
 

@@ -1254,6 +1272,24 @@ static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
 		return 0;
 	}
 
+	/* $current returns the address of the current task_struct. */
+	if (str_has_prefix(arg, "current")) {
+		/* $current is only supported by kernel probe and need function name. */
+		if (!(ctx->flags & TPARG_FL_KERNEL) || !ctx->funcname) {
+			err = TP_ERR_BAD_VAR;
+			goto inval;
+		}
+		arg += strlen("current");
+		if (*arg == '-' && IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS))
+			return parse_btf_arg(orig_arg, pcode, end, ctx);
+
+		if (*arg != '\0')
+			goto inval;
+
+		code->op = FETCH_OP_CURRENT;
+		return 0;
+	}
+
 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 	len = str_has_prefix(arg, "arg");
 	if (len) {

@@ -96,6 +96,7 @@ enum fetch_op {
 	FETCH_OP_FOFFS,		/* File offset: .immediate */
 	FETCH_OP_DATA,		/* Allocated data: .data */
 	FETCH_OP_EDATA,		/* Entry data: .offset */
+	FETCH_OP_CURRENT,	/* Current task_struct address */
 	// Stage 2 (dereference) op
 	FETCH_OP_DEREF,		/* Dereference: .offset */
 	FETCH_OP_UDEREF,	/* User-space Dereference: .offset */

@@ -112,6 +112,9 @@ process_common_fetch_insn(struct fetch_insn *code, unsigned long *val)
 	case FETCH_OP_DATA:
 		*val = (unsigned long)code->data;
 		break;
+	case FETCH_OP_CURRENT:
+		*val = (unsigned long)current;
+		break;
 	default:
 		return -EILSEQ;
 	}