[DTrace-devel] [PATCH v4] cg, printf: allow storing [u]stack() into vars and printf using %k
Eugene Loh
eugene.loh at oracle.com
Tue Oct 7 18:52:52 UTC 2025
Nice feature. Tour de force implementation.
Reviewed-by: Eugene Loh <eugene.loh at oracle.com>
On 10/7/25 01:35, Kris Van Hees via DTrace-devel wrote:
> To support storing [u]stack() values in variables and as arguments for
> printf(), a type definition is introduced:
>
> typedef struct dt_stack {
> uint32_t frames;
> uint32_t strsz; // optional string blob size
> uint32_t is_user // > 0 if userspace stack trace
> uint32_t pid; // process id (or 0 for kernel)
> uint64_t addrs[n]; // stack trace addresses
> } dt_stack_t;
>
> where 'n' is the maximum number of frames that can be retrieved (set
> with the 'maxframes' option).
>
> Since dt_stack_t needs to be known early enough to define stack(),
> jstack(), and ustack(), it is defined in two stages. First dt_stack_t
> is defined as a typedef for struct dt_stack, and once options have been
> processed, struct dt_stack is finalized.
>
> Once the value of a stack has been assigned to a variable, it can be
> accessed as a regular struct (*not* a pointer to a struct).
> Modification is also possible, and safety checks are performed to ensure
> that such modifications do not cause crashes in the consumer.
>
> Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> ---
> libdtrace/dt_cg.c | 84 +++++++++++--------
> libdtrace/dt_dctx.h | 3 +-
> libdtrace/dt_impl.h | 13 ---
> libdtrace/dt_open.c | 62 +++++++++++---
> libdtrace/dt_parser.c | 2 +-
> libdtrace/dt_printf.c | 43 +++++++---
> .../unittest/funcs/stack/err.corrupted-data.d | 25 ++++++
> .../unittest/funcs/stack/err.corrupted-data.r | 4 +
> .../unittest/funcs/stack/err.store-to-stack.d | 23 +++++
> .../unittest/funcs/stack/err.store-to-stack.r | 2 +
> test/unittest/funcs/stack/tst.asgn_dvar.d | 25 ++++++
> test/unittest/funcs/stack/tst.asgn_dvar.r | 1 +
> test/unittest/funcs/stack/tst.asgn_dvar.r.p | 35 ++++++++
> test/unittest/funcs/stack/tst.asgn_gvar.d | 25 ++++++
> test/unittest/funcs/stack/tst.asgn_gvar.r | 1 +
> test/unittest/funcs/stack/tst.asgn_gvar.r.p | 1 +
> test/unittest/funcs/stack/tst.asgn_lvar.d | 25 ++++++
> test/unittest/funcs/stack/tst.asgn_lvar.r | 1 +
> test/unittest/funcs/stack/tst.asgn_lvar.r.p | 1 +
> test/unittest/funcs/stack/tst.asgn_tvar.d | 25 ++++++
> test/unittest/funcs/stack/tst.asgn_tvar.r | 1 +
> test/unittest/funcs/stack/tst.asgn_tvar.r.p | 1 +
> test/unittest/funcs/stack/tst.ref_addrs.d | 24 ++++++
> test/unittest/funcs/stack/tst.ref_addrs.r | 5 ++
> test/unittest/funcs/stack/tst.ref_depth.d | 35 ++++++++
> test/unittest/funcs/stack/tst.ref_depth.r | 6 ++
> test/unittest/funcs/stack/tst.ref_is_user.d | 35 ++++++++
> test/unittest/funcs/stack/tst.ref_is_user.r | 6 ++
> test/unittest/funcs/stack/tst.ref_pid.d | 35 ++++++++
> test/unittest/funcs/stack/tst.ref_pid.r | 6 ++
> test/unittest/funcs/stack/tst.ref_strsz.d | 35 ++++++++
> test/unittest/funcs/stack/tst.ref_strsz.r | 6 ++
> test/unittest/funcs/stack/tst.store.d | 28 +++++++
> test/unittest/funcs/stack/tst.store.r | 1 +
> test/unittest/funcs/stack/tst.store.r.p | 63 ++++++++++++++
> .../funcs/ustack/err.corrupted-data.d | 25 ++++++
> .../funcs/ustack/err.corrupted-data.r | 4 +
> .../funcs/ustack/err.store-to-stack.d | 23 +++++
> .../funcs/ustack/err.store-to-stack.r | 2 +
> test/unittest/funcs/ustack/tst.asgn_dvar.d | 25 ++++++
> test/unittest/funcs/ustack/tst.asgn_dvar.r | 1 +
> test/unittest/funcs/ustack/tst.asgn_dvar.r.p | 60 +++++++++++++
> test/unittest/funcs/ustack/tst.asgn_gvar.d | 25 ++++++
> test/unittest/funcs/ustack/tst.asgn_gvar.r | 1 +
> test/unittest/funcs/ustack/tst.asgn_gvar.r.p | 1 +
> test/unittest/funcs/ustack/tst.asgn_lvar.d | 25 ++++++
> test/unittest/funcs/ustack/tst.asgn_lvar.r | 1 +
> test/unittest/funcs/ustack/tst.asgn_lvar.r.p | 1 +
> test/unittest/funcs/ustack/tst.asgn_tvar.d | 25 ++++++
> test/unittest/funcs/ustack/tst.asgn_tvar.r | 1 +
> test/unittest/funcs/ustack/tst.asgn_tvar.r.p | 1 +
> test/unittest/funcs/ustack/tst.ref_addrs.d | 24 ++++++
> test/unittest/funcs/ustack/tst.ref_addrs.r | 5 ++
> test/unittest/funcs/ustack/tst.ref_depth.d | 35 ++++++++
> test/unittest/funcs/ustack/tst.ref_depth.r | 6 ++
> test/unittest/funcs/ustack/tst.ref_is_user.d | 35 ++++++++
> test/unittest/funcs/ustack/tst.ref_is_user.r | 6 ++
> test/unittest/funcs/ustack/tst.ref_pid.d | 37 ++++++++
> test/unittest/funcs/ustack/tst.ref_strsz.d | 35 ++++++++
> test/unittest/funcs/ustack/tst.ref_strsz.r | 6 ++
> test/unittest/funcs/ustack/tst.store.d | 28 +++++++
> test/unittest/funcs/ustack/tst.store.r | 1 +
> test/unittest/funcs/ustack/tst.store.r.p | 63 ++++++++++++++
> .../printa/err.D_PRINTF_ARG_TYPE.stack.r | 2 +-
> .../printa/err.D_PRINTF_ARG_TYPE.ustack.r | 2 +-
> test/unittest/printf/tst.stack.d | 33 ++++++++
> test/unittest/printf/tst.stack.r | 1 +
> test/unittest/printf/tst.stack.r.p | 75 +++++++++++++++++
> test/unittest/printf/tst.ustack25_pid.d | 21 +++++
> test/unittest/printf/tst.ustack25_pid.r | 28 +++++++
> test/unittest/printf/tst.ustack25_pid.r.p | 37 ++++++++
> 71 files changed, 1313 insertions(+), 76 deletions(-)
> create mode 100644 test/unittest/funcs/stack/err.corrupted-data.d
> create mode 100644 test/unittest/funcs/stack/err.corrupted-data.r
> create mode 100644 test/unittest/funcs/stack/err.store-to-stack.d
> create mode 100644 test/unittest/funcs/stack/err.store-to-stack.r
> create mode 100644 test/unittest/funcs/stack/tst.asgn_dvar.d
> create mode 100644 test/unittest/funcs/stack/tst.asgn_dvar.r
> create mode 100755 test/unittest/funcs/stack/tst.asgn_dvar.r.p
> create mode 100644 test/unittest/funcs/stack/tst.asgn_gvar.d
> create mode 120000 test/unittest/funcs/stack/tst.asgn_gvar.r
> create mode 120000 test/unittest/funcs/stack/tst.asgn_gvar.r.p
> create mode 100644 test/unittest/funcs/stack/tst.asgn_lvar.d
> create mode 120000 test/unittest/funcs/stack/tst.asgn_lvar.r
> create mode 120000 test/unittest/funcs/stack/tst.asgn_lvar.r.p
> create mode 100644 test/unittest/funcs/stack/tst.asgn_tvar.d
> create mode 120000 test/unittest/funcs/stack/tst.asgn_tvar.r
> create mode 120000 test/unittest/funcs/stack/tst.asgn_tvar.r.p
> create mode 100644 test/unittest/funcs/stack/tst.ref_addrs.d
> create mode 100644 test/unittest/funcs/stack/tst.ref_addrs.r
> create mode 100644 test/unittest/funcs/stack/tst.ref_depth.d
> create mode 100644 test/unittest/funcs/stack/tst.ref_depth.r
> create mode 100644 test/unittest/funcs/stack/tst.ref_is_user.d
> create mode 100644 test/unittest/funcs/stack/tst.ref_is_user.r
> create mode 100644 test/unittest/funcs/stack/tst.ref_pid.d
> create mode 100644 test/unittest/funcs/stack/tst.ref_pid.r
> create mode 100644 test/unittest/funcs/stack/tst.ref_strsz.d
> create mode 100644 test/unittest/funcs/stack/tst.ref_strsz.r
> create mode 100644 test/unittest/funcs/stack/tst.store.d
> create mode 100644 test/unittest/funcs/stack/tst.store.r
> create mode 100755 test/unittest/funcs/stack/tst.store.r.p
> create mode 100644 test/unittest/funcs/ustack/err.corrupted-data.d
> create mode 100644 test/unittest/funcs/ustack/err.corrupted-data.r
> create mode 100644 test/unittest/funcs/ustack/err.store-to-stack.d
> create mode 100644 test/unittest/funcs/ustack/err.store-to-stack.r
> create mode 100644 test/unittest/funcs/ustack/tst.asgn_dvar.d
> create mode 100644 test/unittest/funcs/ustack/tst.asgn_dvar.r
> create mode 100755 test/unittest/funcs/ustack/tst.asgn_dvar.r.p
> create mode 100644 test/unittest/funcs/ustack/tst.asgn_gvar.d
> create mode 120000 test/unittest/funcs/ustack/tst.asgn_gvar.r
> create mode 120000 test/unittest/funcs/ustack/tst.asgn_gvar.r.p
> create mode 100644 test/unittest/funcs/ustack/tst.asgn_lvar.d
> create mode 120000 test/unittest/funcs/ustack/tst.asgn_lvar.r
> create mode 120000 test/unittest/funcs/ustack/tst.asgn_lvar.r.p
> create mode 100644 test/unittest/funcs/ustack/tst.asgn_tvar.d
> create mode 120000 test/unittest/funcs/ustack/tst.asgn_tvar.r
> create mode 120000 test/unittest/funcs/ustack/tst.asgn_tvar.r.p
> create mode 100644 test/unittest/funcs/ustack/tst.ref_addrs.d
> create mode 100644 test/unittest/funcs/ustack/tst.ref_addrs.r
> create mode 100644 test/unittest/funcs/ustack/tst.ref_depth.d
> create mode 100644 test/unittest/funcs/ustack/tst.ref_depth.r
> create mode 100644 test/unittest/funcs/ustack/tst.ref_is_user.d
> create mode 100644 test/unittest/funcs/ustack/tst.ref_is_user.r
> create mode 100644 test/unittest/funcs/ustack/tst.ref_pid.d
> create mode 100644 test/unittest/funcs/ustack/tst.ref_strsz.d
> create mode 100644 test/unittest/funcs/ustack/tst.ref_strsz.r
> create mode 100644 test/unittest/funcs/ustack/tst.store.d
> create mode 100644 test/unittest/funcs/ustack/tst.store.r
> create mode 100755 test/unittest/funcs/ustack/tst.store.r.p
> create mode 100644 test/unittest/printf/tst.stack.d
> create mode 100644 test/unittest/printf/tst.stack.r
> create mode 100755 test/unittest/printf/tst.stack.r.p
> create mode 100644 test/unittest/printf/tst.ustack25_pid.d
> create mode 100644 test/unittest/printf/tst.ustack25_pid.r
> create mode 100755 test/unittest/printf/tst.ustack25_pid.r.p
>
> diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
> index 3ce13c74..ec4e3123 100644
> --- a/libdtrace/dt_cg.c
> +++ b/libdtrace/dt_cg.c
> @@ -2647,11 +2647,16 @@ dt_cg_act_speculate(dt_pcb_t *pcb, dt_node_t *dnp, dtrace_actkind_t kind)
> dt_regset_free(drp, dnp->dn_reg);
> }
>
> -static uint64_t
> -dt_cg_stack_arg(dtrace_hdl_t *dtp, dt_node_t *dnp, dtrace_actkind_t kind)
> +/*
> + * Extract [u]stack() argument data, storing number of frames and optional
> + * string data in '*nframesp' and '*strszp', and returning the storage size for
> + * the call stack data (not including the size of the optional string data).
> + */
> +static uint_t
> +dt_cg_stack_arg(dtrace_hdl_t *dtp, dt_node_t *dnp, dtrace_actkind_t kind,
> + uint_t *nframesp, uint_t *strszp)
> {
> - int nframes;
> - int strsize = 0;
> + uint_t nframes;
> dt_node_t *arg0 = dnp->dn_args;
> dt_node_t *arg1 = arg0 != NULL ? arg0->dn_list : NULL;
> int indopt, def, inderr;
> @@ -2689,19 +2694,24 @@ dt_cg_stack_arg(dtrace_hdl_t *dtp, dt_node_t *dnp, dtrace_actkind_t kind)
> if (nframes > dtp->dt_options[DTRACEOPT_MAXFRAMES])
> nframes = dtp->dt_options[DTRACEOPT_MAXFRAMES];
>
> - /* For user stacks, process one more argument. */
> - if (kind == DTRACEACT_USTACK && arg1 != NULL) {
> - if (arg1->dn_kind != DT_NODE_INT ||
> - ((arg1->dn_flags & DT_NF_SIGNED) &&
> - (int64_t)arg1->dn_value < 0))
> - dnerror(arg1, D_USTACK_STRSIZE,
> - "ustack( ) argument #2 must be a positive integer constant\n");
> + if (nframesp)
> + *nframesp = nframes;
> +
> + if (strszp) {
> + /* For user stacks, process one more argument. */
> + if (kind == DTRACEACT_USTACK && arg1 != NULL) {
> + if (arg1->dn_kind != DT_NODE_INT ||
> + ((arg1->dn_flags & DT_NF_SIGNED) &&
> + (int64_t)arg1->dn_value < 0))
> + dnerror(arg1, D_USTACK_STRSIZE,
> + "ustack( ) argument #2 must be a positive integer constant\n");
>
> - /* FIXME: for now, accept non-zero strsize, but it does nothing */
> - strsize = arg1->dn_value;
> + *strszp = arg1->dn_value;
> + } else
> + *strszp = 0;
> }
>
> - return DTRACE_STACK_ARG(kind == DTRACEACT_USTACK, nframes, strsize);
> + return 4 * sizeof(uint32_t) + nframes * sizeof(uint64_t);
> }
>
> /*
> @@ -2729,28 +2739,30 @@ dt_cg_act_stack_sub(dt_pcb_t *pcb, dt_node_t *dnp, int reg, int off,
> dtrace_hdl_t *dtp = pcb->pcb_hdl;
> dt_irlist_t *dlp = &pcb->pcb_ir;
> dt_regset_t *drp = pcb->pcb_regs;
> - uint64_t arg;
> - int nframes, stacksize, prefsz, align = sizeof(uint64_t);
> + int allocsz, nframes = 0, strsz = 0, aloff;
> uint_t lbl_valid = dt_irlist_label(dlp);
> dt_ident_t *skip = dt_dlib_get_var(dtp, "STACK_SKIP");
>
> assert(skip != NULL);
>
> /* Get sizing information from dnp->dn_arg. */
> - arg = dt_cg_stack_arg(dtp, dnp, kind);
> - prefsz = kind == DTRACEACT_USTACK ? sizeof(uint64_t) : 0;
> - nframes = DTRACE_STACK_NFRAMES(arg);
> - stacksize = nframes * sizeof(uint64_t);
> + allocsz = dt_cg_stack_arg(dtp, dnp, kind, &nframes, &strsz);
>
> /* Handle alignment and reserve space in the output buffer. */
> if (reg >= 0) {
> - off = ALIGN(off, align);
> + aloff = ALIGN(off, 8);
> } else {
> reg = BPF_REG_9;
> - off = dt_rec_add(dtp, dt_cg_fill_gap, kind,
> - prefsz + stacksize, align, NULL, arg);
> + aloff = off = dt_rec_add(dtp, dt_cg_fill_gap, kind, allocsz, 8,
> + NULL, 0);
> }
>
> + /* Store the stack trace meta-data (type, depth, strsize). */
> + emit(dlp, BPF_STORE_IMM(BPF_W, reg, aloff, nframes));
> + emit(dlp, BPF_STORE_IMM(BPF_W, reg, aloff + 4, strsz));
> + emit(dlp, BPF_STORE_IMM(BPF_W, reg, aloff + 8,
> + kind == DTRACEACT_USTACK ? 1 : 0));
> +
> /* Write the tgid. */
> if (kind == DTRACEACT_USTACK) {
> if (dt_regset_xalloc_args(drp) == -1)
> @@ -2758,19 +2770,19 @@ dt_cg_act_stack_sub(dt_pcb_t *pcb, dt_node_t *dnp, int reg, int off,
> dt_regset_xalloc(drp, BPF_REG_0);
> emit(dlp, BPF_CALL_HELPER(BPF_FUNC_get_current_pid_tgid));
> dt_regset_free_args(drp);
> - /* mov32 %r0, %r0 effectively masks the lower 32 bits. */
> - emit(dlp, BPF_MOV32_REG(BPF_REG_0, BPF_REG_0));
> - emit(dlp, BPF_STORE(BPF_DW, reg, off, BPF_REG_0));
> + /* A 32-bit store effectively masks the lower 32 bits. */
> + emit(dlp, BPF_STORE(BPF_W, reg, aloff + 12, BPF_REG_0));
> dt_regset_free(drp, BPF_REG_0);
> - }
> + } else
> + emit(dlp, BPF_STORE_IMM(BPF_W, reg, aloff + 12, 0));
>
> /* Call bpf_get_stack(ctx, buf, size, flags). */
> if (dt_regset_xalloc_args(drp) == -1)
> longjmp(yypcb->pcb_jmpbuf, EDT_NOREG);
> dt_cg_access_dctx(BPF_REG_1, dlp, drp, DCTX_CTX);
> emit(dlp, BPF_MOV_REG(BPF_REG_2, reg));
> - emit(dlp, BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, off + prefsz));
> - emit(dlp, BPF_MOV_IMM(BPF_REG_3, stacksize));
> + emit(dlp, BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, aloff + 16));
> + emit(dlp, BPF_MOV_IMM(BPF_REG_3, nframes * sizeof(uint64_t)));
> if (kind == DTRACEACT_USTACK)
> emit(dlp, BPF_MOV_IMM(BPF_REG_4, BPF_F_USER_STACK));
> else {
> @@ -2786,7 +2798,7 @@ dt_cg_act_stack_sub(dt_pcb_t *pcb, dt_node_t *dnp, int reg, int off,
> emitl(dlp, lbl_valid,
> BPF_NOP());
>
> - return prefsz + stacksize;
> + return (aloff - off) + allocsz;
> }
>
> static void
> @@ -8735,15 +8747,13 @@ dt_cg_agg(dt_pcb_t *pcb, dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
>
> if (idp->di_kind == DT_IDENT_FUNC) {
> switch (idp->di_id) {
> - case DIF_SUBR_USTACK:
> - arg = dt_cg_stack_arg(dtp, knp, DTRACEACT_USTACK);
> - kind = DTRACEACT_USTACK;
> - size = 8 + 8 * DTRACE_STACK_NFRAMES(arg);
> - goto add_rec;
> case DIF_SUBR_STACK:
> - arg = dt_cg_stack_arg(dtp, knp, DTRACEACT_STACK);
> kind = DTRACEACT_STACK;
> - size = 8 * arg;
> + goto is_stack;
> + case DIF_SUBR_USTACK:
> + kind = DTRACEACT_USTACK;
> +is_stack:
> + size = dt_cg_stack_arg(dtp, knp, kind, NULL, NULL);
> goto add_rec;
> }
> } else if (idp->di_kind == DT_IDENT_ACTFUNC) {
> diff --git a/libdtrace/dt_dctx.h b/libdtrace/dt_dctx.h
> index b50a1395..5bf21345 100644
> --- a/libdtrace/dt_dctx.h
> +++ b/libdtrace/dt_dctx.h
> @@ -128,7 +128,8 @@ typedef struct dt_dctx {
> * completed.
> */
> #define DMEM_STACK_SZ(dtp) \
> - (sizeof(uint64_t) * (dtp)->dt_options[DTRACEOPT_MAXFRAMES] + 1)
> + (4 * sizeof(uint32_t) + \
> + (dtp)->dt_options[DTRACEOPT_MAXFRAMES] * sizeof(uint64_t))
> #define DMEM_TSTR_SZ(dtp) \
> (DT_TSTRING_SLOTS * DT_TSTRING_SIZE(dtp))
> #define DMEM_STRTOK_SZ(dtp) \
> diff --git a/libdtrace/dt_impl.h b/libdtrace/dt_impl.h
> index aa81906f..3b0b2358 100644
> --- a/libdtrace/dt_impl.h
> +++ b/libdtrace/dt_impl.h
> @@ -236,19 +236,6 @@ typedef struct dt_tstring {
> int in_use; /* In use (1) or not (0) */
> } dt_tstring_t;
>
> -/*
> - * The stack()/ustack() data record argument encodes:
> - * - the stack type (kernel or userspace)
> - * - the number of frames in the stack trace
> - * - the size of the optional string area for ustack()
> - */
> -#define DTRACE_STACK_IS_USER(x) ((x) & (1 << 31))
> -#define DTRACE_STACK_NFRAMES(x) (uint32_t)((x) & INT32_MAX)
> -#define DTRACE_STACK_STRSIZE(x) (uint32_t)((x) >> 32)
> -#define DTRACE_STACK_ARG(t, x, y) ((((uint64_t)(y)) << 32) | \
> - ((t) ? (1UL << 31) : 0) | \
> - ((x) & INT32_MAX))
> -
> typedef struct dt_dirpath {
> dt_list_t dir_list; /* linked-list forward/back pointers */
> char *dir_path; /* directory pathname */
> diff --git a/libdtrace/dt_open.c b/libdtrace/dt_open.c
> index ba5463a0..17dfbf9a 100644
> --- a/libdtrace/dt_open.c
> +++ b/libdtrace/dt_open.c
> @@ -175,7 +175,7 @@ static const dt_ident_t _dtrace_globals[] = {
> { "ipl", DT_IDENT_SCALAR, 0, DIF_VAR_IPL, DT_ATTR_STABCMN, DT_VERS_1_0,
> &dt_idops_type, "uint_t" },
> { "jstack", DT_IDENT_ACTFUNC, 0, DT_ACT_JSTACK, DT_ATTR_STABCMN, DT_VERS_1_0,
> - &dt_idops_func, "dt_stack([uint32_t], [uint32_t])" },
> + &dt_idops_func, "dt_stack_t([uint32_t], [uint32_t])" },
> { "link_ntop", DT_IDENT_FUNC, 0, DIF_SUBR_LINK_NTOP, DT_ATTR_STABCMN,
> DT_VERS_1_5, &dt_idops_func, "string(int, void *)" },
> { "llquantize", DT_IDENT_AGGFUNC, 0, DT_AGG_LLQUANTIZE,
> @@ -274,7 +274,7 @@ static const dt_ident_t _dtrace_globals[] = {
> DT_ATTR_STABCMN, DT_VERS_1_0,
> &dt_idops_func, "int()" },
> { "stack", DT_IDENT_FUNC, DT_IDFLG_DPTR, DIF_SUBR_STACK, DT_ATTR_STABCMN,
> - DT_VERS_1_0, &dt_idops_func, "dt_stack([uint32_t])" },
> + DT_VERS_1_0, &dt_idops_func, "dt_stack_t([uint32_t])" },
> { "stackdepth", DT_IDENT_SCALAR, 0, DIF_VAR_STACKDEPTH,
> DT_ATTR_STABCMN, DT_VERS_1_0,
> &dt_idops_type, "uint32_t" },
> @@ -329,7 +329,7 @@ static const dt_ident_t _dtrace_globals[] = {
> { "uregs", DT_IDENT_ARRAY, 0, DIF_VAR_UREGS, DT_ATTR_STABCMN, DT_VERS_1_0,
> &dt_idops_regs, NULL },
> { "ustack", DT_IDENT_FUNC, DT_IDFLG_DPTR, DIF_SUBR_USTACK, DT_ATTR_STABCMN,
> - DT_VERS_1_0, &dt_idops_func, "dt_stack([uint32_t], [uint32_t])" },
> + DT_VERS_1_0, &dt_idops_func, "dt_stack_t([uint32_t], [uint32_t])" },
> { "ustackdepth", DT_IDENT_SCALAR, 0, DIF_VAR_USTACKDEPTH,
> DT_ATTR_STABCMN, DT_VERS_1_2,
> &dt_idops_type, "uint32_t" },
> @@ -1058,16 +1058,33 @@ dt_vopen(int version, int flags, int *errp,
> "<DYN>", ctf_lookup_by_name(dmp->dm_ctfp, "void"));
>
> /*
> - * The stack type is added as a typedef of uint64_t[MAXFRAMES]. The
> - * final value of MAXFRAMES may be adjusted with the "stackframes"
> - * option.
> + * Define:
> + * typedef struct dt_stack {
> + * uint32_t frames;
> + * uint32_t strsz; // optional string blob size
> + * uint32_t is_user; // > 0 if userspace stack
> + * uint32_t pid; // process id (or 0 for kernel)
> + * uint64_t addrs[n]; // stack trace addresses
> + * } dt_stack_t;
> + *
> + * It is done in two stages because we won't know the size of the addrs
> + * array until runtime options have been processed. We add all members
> + * (except for addrs) here, and then append the addrs array in
> + * dtrace_init().
> */
> - ctr.ctr_contents = ctf_lookup_by_name(dmp->dm_ctfp, "uint64_t");
> - ctr.ctr_index = ctf_lookup_by_name(dmp->dm_ctfp, "long");
> - ctr.ctr_nelems = _dtrace_stackframes;
> -
> - dtp->dt_type_stack = ctf_add_typedef(dmp->dm_ctfp, CTF_ADD_ROOT,
> - "dt_stack", ctf_add_array(dmp->dm_ctfp, CTF_ADD_ROOT, &ctr));
> + {
> + ctf_id_t stid, mbid;
> +
> + stid = ctf_add_struct(dmp->dm_ctfp, CTF_ADD_ROOT, "dt_stack");
> + dtp->dt_type_stack = ctf_add_typedef(dmp->dm_ctfp, CTF_ADD_ROOT,
> + "dt_stack_t", stid);
> +
> + mbid = ctf_lookup_by_name(dmp->dm_ctfp, "uint32_t");
> + ctf_add_member(dmp->dm_ctfp, stid, "depth", mbid);
> + ctf_add_member(dmp->dm_ctfp, stid, "strsz", mbid);
> + ctf_add_member(dmp->dm_ctfp, stid, "is_user", mbid);
> + ctf_add_member(dmp->dm_ctfp, stid, "pid", mbid);
> + }
>
> dtp->dt_type_symaddr = ctf_add_typedef(dmp->dm_ctfp, CTF_ADD_ROOT,
> "_symaddr", ctf_lookup_by_name(dmp->dm_ctfp, "void"));
> @@ -1174,6 +1191,27 @@ dtrace_init(dtrace_hdl_t *dtp)
> int i;
> dtrace_optval_t lockmem = dtp->dt_options[DTRACEOPT_LOCKMEM];
> struct rlimit rl;
> + dt_module_t *dmp = dtp->dt_ddefs;
> + ctf_id_t stid;
> + ctf_arinfo_t ctr;
> +
> + /*
> + * Finalize 'struct dt_stack' now that we know the maxframes value.
> + */
> + stid = ctf_lookup_by_name(dmp->dm_ctfp, "struct dt_stack");
> +
> + ctr.ctr_contents = ctf_lookup_by_name(dmp->dm_ctfp, "uint64_t");
> + ctr.ctr_index = ctf_lookup_by_name(dmp->dm_ctfp, "long");
> + ctr.ctr_nelems = (uint_t)dtp->dt_options[DTRACEOPT_MAXFRAMES];
> +
> + ctf_add_member(dmp->dm_ctfp, stid, "addrs",
> + ctf_add_array(dmp->dm_ctfp, CTF_ADD_ROOT, &ctr));
> +
> + if (ctf_update(dmp->dm_ctfp) != 0) {
> + dt_dprintf("failed update D container: %s\n",
> + ctf_errmsg(ctf_errno(dmp->dm_ctfp)));
> + return dt_set_errno(dtp, EDT_CTF);
> + }
>
> /*
> * Initialize the BPF library handling.
> diff --git a/libdtrace/dt_parser.c b/libdtrace/dt_parser.c
> index 006b4b6e..e71c0985 100644
> --- a/libdtrace/dt_parser.c
> +++ b/libdtrace/dt_parser.c
> @@ -3794,7 +3794,7 @@ dt_cook_op2(dt_node_t *dnp, uint_t idflags)
> * described in the ANSI-C spec (see K&R[A7.17]). We share
> * most of this code with the argument list checking code.
> */
> - if (!dt_node_is_string(lp)) {
> + if (!dt_node_is_string(lp) && !dt_node_is_stack(lp)) {
> kind = ctf_type_kind(lp->dn_ctfp,
> ctf_type_resolve(lp->dn_ctfp, lp->dn_type));
>
> diff --git a/libdtrace/dt_printf.c b/libdtrace/dt_printf.c
> index a3e15397..4f814c4e 100644
> --- a/libdtrace/dt_printf.c
> +++ b/libdtrace/dt_printf.c
> @@ -449,7 +449,8 @@ dt_print_stack_user(dtrace_hdl_t *dtp, FILE *fp, const char *format,
> if (depth == 0)
> return 0;
>
> - tgid = (pid_t)*pc++;
> + tgid = ((uint32_t *)pc)[1];
> + pc++;
>
> if (format == NULL)
> format = "%s";
> @@ -569,18 +570,41 @@ dt_print_stack_user(dtrace_hdl_t *dtp, FILE *fp, const char *format,
> return err;
> }
>
> -/*ARGSUSED*/
> +/*
> + * The data at vaddr is structured as follows:
> + * uint32_t depth
> + * uint32_t strsz
> + * uint32_t is_user
> + * uint32_t pid
> + * uint64_t addrs[depth]
> + *
> + * The 'depth' member provides the maximum number of addresses in the stack
> + * trace.
> + * The 'strsz' member provides the size of the optional string blob that is
> + * appended to the stack trace data.
> + * The 'is_user' member identifies the stack trace as a userspace stack trace
> + * if its value is > 0.
> + * The 'pid' member provides the userspace process id for userspace stack
> + * traces and otherwise will be 0.
> + * The 'addrs' array provides the stack traces addresses. If the stack trace
> + * is shorter than 'depth', remaining addresses will be 0 and can be ignored.
> + */
> static int
> pfprint_stack(dtrace_hdl_t *dtp, FILE *fp, const char *format,
> const dt_pfargd_t *pfd, const void *vaddr, size_t size,
> uint64_t normal, uint64_t sig)
> {
> int width;
> - const dtrace_recdesc_t *rec = pfd->pfd_rec;
> - caddr_t addr = (caddr_t)vaddr;
> - uint32_t depth = DTRACE_STACK_NFRAMES(rec->dtrd_arg);
> + uint32_t *vals = (uint32_t *)vaddr;
> + uint32_t depth = vals[0];
> + uint32_t strsz = vals[1];
> + uint32_t is_user = vals[2];
> + caddr_t addr = (caddr_t)(vals + (is_user ? 2 : 4));
> int err = 0;
>
> + if (depth > dtp->dt_options[DTRACEOPT_MAXFRAMES])
> + return dt_set_errno(dtp, EDT_DSIZE);
> +
> if (depth == 0)
> return 0;
>
> @@ -603,9 +627,9 @@ pfprint_stack(dtrace_hdl_t *dtp, FILE *fp, const char *format,
> if (dt_printf(dtp, fp, "\n") < 0)
> return -1;
>
> - if (DTRACE_STACK_IS_USER(rec->dtrd_arg))
> + if (is_user)
> err = dt_print_stack_user(dtp, fp, format, addr, width, depth,
> - DTRACE_STACK_STRSIZE(rec->dtrd_arg));
> + strsz);
> else
> err = dt_print_stack_kernel(dtp, fp, format, addr, width, depth);
>
> @@ -777,7 +801,7 @@ static const dt_pfconv_t _dtrace_conversions[] = {
> { "hx", "x", "short", pfcheck_xshort, pfprint_uint },
> { "hX", "X", "short", pfcheck_xshort, pfprint_uint },
> { "i", "i", pfproto_xint, pfcheck_dint, pfprint_dint },
> -{ "k", "s", "stack", pfcheck_stack, pfprint_stack },
> +{ "k", "s", "dt_stack_t", pfcheck_stack, pfprint_stack },
> { "lc", "lc", "int", pfcheck_type, pfprint_sint }, /* a.k.a. wint_t */
> { "ld", "d", "long", pfcheck_type, pfprint_sint },
> { "li", "i", "long", pfcheck_type, pfprint_sint },
> @@ -2487,9 +2511,8 @@ dt_print_stack(dtrace_hdl_t *dtp, FILE *fp, void *fmtdata,
> else
> format = ((dt_pfargv_t *)fmtdata)->pfv_format;
>
> - /* pfprint_stack() uses pfd_rec, pfd_flags, and pfd_width only */
> + /* pfprint_stack() uses pfd_flags and pfd_width only */
> memset(&pfd, 0, sizeof(pfd));
> - pfd.pfd_rec = recs;
> pfd.pfd_flags = DT_PFCONV_LEFT;
>
> if (dtp->dt_options[DTRACEOPT_STACKINDENT] != DTRACEOPT_UNSET)
> diff --git a/test/unittest/funcs/stack/err.corrupted-data.d b/test/unittest/funcs/stack/err.corrupted-data.d
> new file mode 100644
> index 00000000..d35361eb
> --- /dev/null
> +++ b/test/unittest/funcs/stack/err.corrupted-data.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Corrupted stack data does not cause a crash.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + v = stack(5);
> + v.depth = 0x7fffffff;
> + printf("%k", v);
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/err.corrupted-data.r b/test/unittest/funcs/stack/err.corrupted-data.r
> new file mode 100644
> index 00000000..1a2b8d2b
> --- /dev/null
> +++ b/test/unittest/funcs/stack/err.corrupted-data.r
> @@ -0,0 +1,4 @@
> + FUNCTION:NAME
> + hrtimer_nanosleep:entry -- @@stderr --
> +dtrace: script 'test/unittest/funcs/stack/err.corrupted-data.d' matched 2 probes
> +dtrace: processing aborted: Data record has incorrect size
> diff --git a/test/unittest/funcs/stack/err.store-to-stack.d b/test/unittest/funcs/stack/err.store-to-stack.d
> new file mode 100644
> index 00000000..2125c395
> --- /dev/null
> +++ b/test/unittest/funcs/stack/err.store-to-stack.d
> @@ -0,0 +1,23 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Assigning a member in stack() is not allowed.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + stack(5).depth = 2;
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/err.store-to-stack.r b/test/unittest/funcs/stack/err.store-to-stack.r
> new file mode 100644
> index 00000000..1b0fb044
> --- /dev/null
> +++ b/test/unittest/funcs/stack/err.store-to-stack.r
> @@ -0,0 +1,2 @@
> +-- @@stderr --
> +dtrace: failed to compile script test/unittest/funcs/stack/err.store-to-stack.d: line 16: operator = requires modifiable lvalue as an operand
> diff --git a/test/unittest/funcs/stack/tst.asgn_dvar.d b/test/unittest/funcs/stack/tst.asgn_dvar.d
> new file mode 100644
> index 00000000..fd32c7b0
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_dvar.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test assignment of stack() to a dynamic variable (assoc element).
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + assoc["a"] = stack(3);
> + printf("%k", assoc["a"]);
> +
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.asgn_dvar.r b/test/unittest/funcs/stack/tst.asgn_dvar.r
> new file mode 100644
> index 00000000..2e9ba477
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_dvar.r
> @@ -0,0 +1 @@
> +success
> diff --git a/test/unittest/funcs/stack/tst.asgn_dvar.r.p b/test/unittest/funcs/stack/tst.asgn_dvar.r.p
> new file mode 100755
> index 00000000..2bc2077d
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_dvar.r.p
> @@ -0,0 +1,35 @@
> +#!/usr/bin/gawk -f
> +
> +/hrtimer_nanosleep/ {
> + # check probe
> + if ( $1 != "hrtimer_nanosleep:entry" ) {
> + print "ERROR: expected fun:prb = hrtimer_nanosleep:entry";
> + exit(0);
> + }
> +
> + # check stack(3)
> + getline;
> + if (index($1, "`hrtimer_nanosleep+0x") == 0 &&
> + match($1, "`hrtimer_nanosleep$") == 0) {
> + print "ERROR: expected leaf frame to be hrtimer_nanosleep";
> + exit(0);
> + }
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing second frame";
> + exit(0);
> + }
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing third frame";
> + exit(0);
> + }
> + getline;
> + if (NF > 0) {
> + print "ERROR: expected stack(3) to have only three frames";
> + exit(0);
> + }
> +
> + print "success";
> + exit(0);
> +}
> diff --git a/test/unittest/funcs/stack/tst.asgn_gvar.d b/test/unittest/funcs/stack/tst.asgn_gvar.d
> new file mode 100644
> index 00000000..06e75430
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_gvar.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test assignment of stack() to a global variable.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + v = stack(3);
> + printf("%k", v);
> +
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.asgn_gvar.r b/test/unittest/funcs/stack/tst.asgn_gvar.r
> new file mode 120000
> index 00000000..a79e4237
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_gvar.r
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r
> \ No newline at end of file
> diff --git a/test/unittest/funcs/stack/tst.asgn_gvar.r.p b/test/unittest/funcs/stack/tst.asgn_gvar.r.p
> new file mode 120000
> index 00000000..2ca41971
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_gvar.r.p
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r.p
> \ No newline at end of file
> diff --git a/test/unittest/funcs/stack/tst.asgn_lvar.d b/test/unittest/funcs/stack/tst.asgn_lvar.d
> new file mode 100644
> index 00000000..1b63d20a
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_lvar.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test assignment of stack() to a local variable.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + this->v = stack(3);
> + printf("%k", this->v);
> +
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.asgn_lvar.r b/test/unittest/funcs/stack/tst.asgn_lvar.r
> new file mode 120000
> index 00000000..a79e4237
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_lvar.r
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r
> \ No newline at end of file
> diff --git a/test/unittest/funcs/stack/tst.asgn_lvar.r.p b/test/unittest/funcs/stack/tst.asgn_lvar.r.p
> new file mode 120000
> index 00000000..2ca41971
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_lvar.r.p
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r.p
> \ No newline at end of file
> diff --git a/test/unittest/funcs/stack/tst.asgn_tvar.d b/test/unittest/funcs/stack/tst.asgn_tvar.d
> new file mode 100644
> index 00000000..9722290b
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_tvar.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test assignment of stack() to a TLS variable.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + self->v = stack(3);
> + printf("%k", self->v);
> +
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.asgn_tvar.r b/test/unittest/funcs/stack/tst.asgn_tvar.r
> new file mode 120000
> index 00000000..a79e4237
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_tvar.r
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r
> \ No newline at end of file
> diff --git a/test/unittest/funcs/stack/tst.asgn_tvar.r.p b/test/unittest/funcs/stack/tst.asgn_tvar.r.p
> new file mode 120000
> index 00000000..2ca41971
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.asgn_tvar.r.p
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r.p
> \ No newline at end of file
> diff --git a/test/unittest/funcs/stack/tst.ref_addrs.d b/test/unittest/funcs/stack/tst.ref_addrs.d
> new file mode 100644
> index 00000000..8ea385f7
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_addrs.d
> @@ -0,0 +1,24 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'addrs' array of a kernel stack.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + trace("Expecting vmlinux`hrtimer_nanosleep, got ");
> + func(stack(7).addrs[0]);
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.ref_addrs.r b/test/unittest/funcs/stack/tst.ref_addrs.r
> new file mode 100644
> index 00000000..f209b8ed
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_addrs.r
> @@ -0,0 +1,5 @@
> + FUNCTION:NAME
> + hrtimer_nanosleep:entry Expecting vmlinux`hrtimer_nanosleep, got vmlinux`hrtimer_nanosleep
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/stack/tst.ref_addrs.d' matched 2 probes
> diff --git a/test/unittest/funcs/stack/tst.ref_depth.d b/test/unittest/funcs/stack/tst.ref_depth.d
> new file mode 100644
> index 00000000..0a8ce390
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_depth.d
> @@ -0,0 +1,35 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'depth' field of a kernel stack.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + trace("Expecting 7, got ");
> + trace(stack(7).depth);
> +}
> +
> +fbt::hrtimer_nanosleep:entry
> +/stack(7).depth == 7/
> +{
> + exit(0);
> +}
> +
> +fbt::hrtimer_nanosleep:entry
> +/stack(7).depth != 7/
> +{
> + exit(1);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.ref_depth.r b/test/unittest/funcs/stack/tst.ref_depth.r
> new file mode 100644
> index 00000000..10a70b58
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_depth.r
> @@ -0,0 +1,6 @@
> + FUNCTION:NAME
> + hrtimer_nanosleep:entry Expecting 7, got 7
> + hrtimer_nanosleep:entry
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/stack/tst.ref_depth.d' matched 4 probes
> diff --git a/test/unittest/funcs/stack/tst.ref_is_user.d b/test/unittest/funcs/stack/tst.ref_is_user.d
> new file mode 100644
> index 00000000..076fe289
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_is_user.d
> @@ -0,0 +1,35 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'is_user' field of a kernel stack.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + trace("Expecting 0, got ");
> + trace(stack(7).is_user);
> +}
> +
> +fbt::hrtimer_nanosleep:entry
> +/stack(7).is_user == 0/
> +{
> + exit(0);
> +}
> +
> +fbt::hrtimer_nanosleep:entry
> +/stack(7).is_user != 0/
> +{
> + exit(1);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.ref_is_user.r b/test/unittest/funcs/stack/tst.ref_is_user.r
> new file mode 100644
> index 00000000..78259b48
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_is_user.r
> @@ -0,0 +1,6 @@
> + FUNCTION:NAME
> + hrtimer_nanosleep:entry Expecting 0, got 0
> + hrtimer_nanosleep:entry
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/stack/tst.ref_is_user.d' matched 4 probes
> diff --git a/test/unittest/funcs/stack/tst.ref_pid.d b/test/unittest/funcs/stack/tst.ref_pid.d
> new file mode 100644
> index 00000000..db64d5fb
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_pid.d
> @@ -0,0 +1,35 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'pid' field of a kernel stack yields 0.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + trace("Expecting 0, got ");
> + trace(stack(7).pid);
> +}
> +
> +fbt::hrtimer_nanosleep:entry
> +/stack(7).pid == 0/
> +{
> + exit(0);
> +}
> +
> +fbt::hrtimer_nanosleep:entry
> +/stack(7).pid != 0/
> +{
> + exit(1);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.ref_pid.r b/test/unittest/funcs/stack/tst.ref_pid.r
> new file mode 100644
> index 00000000..30f4541d
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_pid.r
> @@ -0,0 +1,6 @@
> + FUNCTION:NAME
> + hrtimer_nanosleep:entry Expecting 0, got 0
> + hrtimer_nanosleep:entry
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/stack/tst.ref_pid.d' matched 4 probes
> diff --git a/test/unittest/funcs/stack/tst.ref_strsz.d b/test/unittest/funcs/stack/tst.ref_strsz.d
> new file mode 100644
> index 00000000..3ec5efcf
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_strsz.d
> @@ -0,0 +1,35 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'strsz' field of a kernel stack yields 0.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + trace("Expecting 0, got ");
> + trace(stack(7).strsz);
> +}
> +
> +fbt::hrtimer_nanosleep:entry
> +/stack(7).strsz == 0/
> +{
> + exit(0);
> +}
> +
> +fbt::hrtimer_nanosleep:entry
> +/stack(7).strsz != 0/
> +{
> + exit(1);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.ref_strsz.r b/test/unittest/funcs/stack/tst.ref_strsz.r
> new file mode 100644
> index 00000000..3fff4fea
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.ref_strsz.r
> @@ -0,0 +1,6 @@
> + FUNCTION:NAME
> + hrtimer_nanosleep:entry Expecting 0, got 0
> + hrtimer_nanosleep:entry
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/stack/tst.ref_strsz.d' matched 4 probes
> diff --git a/test/unittest/funcs/stack/tst.store.d b/test/unittest/funcs/stack/tst.store.d
> new file mode 100644
> index 00000000..6d113596
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.store.d
> @@ -0,0 +1,28 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: It is possible to store to members of dt_stack_t.
> + */
> +
> +/* @@trigger: periodic_output */
> +
> +fbt::hrtimer_nanosleep:entry
> +{
> + v = stack(3);
> + printf("%k", v);
> + v.depth = 2;
> + printf("%k", v);
> + v.depth = 3;
> + printf("%k", v);
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/stack/tst.store.r b/test/unittest/funcs/stack/tst.store.r
> new file mode 100644
> index 00000000..2e9ba477
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.store.r
> @@ -0,0 +1 @@
> +success
> diff --git a/test/unittest/funcs/stack/tst.store.r.p b/test/unittest/funcs/stack/tst.store.r.p
> new file mode 100755
> index 00000000..cd1bc568
> --- /dev/null
> +++ b/test/unittest/funcs/stack/tst.store.r.p
> @@ -0,0 +1,63 @@
> +#!/usr/bin/gawk -f
> +
> +/hrtimer_nanosleep/ {
> + # check probe
> + if ( $1 != "hrtimer_nanosleep:entry" ) {
> + print "ERROR: expected fun:prb = hrtimer_nanosleep:entry";
> + exit(0);
> + }
> +
> + # collect 3 stack frames
> + for (i = 0; i < 3; i++) {
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing stack(3) frame addrs["i"]";
> + exit(0);
> + }
> + stack[i] = $0;
> + }
> + getline;
> + if (NF != 0) {
> + print "ERROR: too many stack frames (first stack(3))";
> + exit(0);
> + }
> +
> + # expect 2 stack frames
> + for (i = 0; i < 2; i++) {
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing stack(2) frame addrs["i"]";
> + exit(0);
> + }
> + if (stack[i] != $0) {
> + print "ERROR: wrong stack(2) frame addrs["i"]";
> + exit(0);
> + }
> + }
> + getline;
> + if (NF != 0) {
> + print "ERROR: too many stack frames (stack(2))";
> + exit(0);
> + }
> +
> + # expect 3 stack frames
> + for (i = 0; i < 3; i++) {
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing stack(3) frame addrs["i"]";
> + exit(0);
> + }
> + if (stack[i] != $0) {
> + print "ERROR: wrong stack(3) frame addrs["i"]";
> + exit(0);
> + }
> + }
> + getline;
> + if (NF != 0) {
> + print "ERROR: too many stack frames (second stack(3))";
> + exit(0);
> + }
> +
> + print "success";
> + exit(0);
> +}
> diff --git a/test/unittest/funcs/ustack/err.corrupted-data.d b/test/unittest/funcs/ustack/err.corrupted-data.d
> new file mode 100644
> index 00000000..c4525aaf
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/err.corrupted-data.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Corrupted stack data does not cause a crash.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + v = ustack(5);
> + v.depth = 0x7fffffff;
> + printf("%k", v);
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/err.corrupted-data.r b/test/unittest/funcs/ustack/err.corrupted-data.r
> new file mode 100644
> index 00000000..8ad0244f
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/err.corrupted-data.r
> @@ -0,0 +1,4 @@
> + FUNCTION:NAME
> + myfunc_z:entry -- @@stderr --
> +dtrace: script 'test/unittest/funcs/ustack/err.corrupted-data.d' matched 2 probes
> +dtrace: processing aborted: Data record has incorrect size
> diff --git a/test/unittest/funcs/ustack/err.store-to-stack.d b/test/unittest/funcs/ustack/err.store-to-stack.d
> new file mode 100644
> index 00000000..106c0cd9
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/err.store-to-stack.d
> @@ -0,0 +1,23 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Assigning a member in ustack() is not allowed.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + ustack(5).depth = 2;
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/err.store-to-stack.r b/test/unittest/funcs/ustack/err.store-to-stack.r
> new file mode 100644
> index 00000000..3a0aeba5
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/err.store-to-stack.r
> @@ -0,0 +1,2 @@
> +-- @@stderr --
> +dtrace: failed to compile script test/unittest/funcs/ustack/err.store-to-stack.d: line 16: operator = requires modifiable lvalue as an operand
> diff --git a/test/unittest/funcs/ustack/tst.asgn_dvar.d b/test/unittest/funcs/ustack/tst.asgn_dvar.d
> new file mode 100644
> index 00000000..142a56ce
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_dvar.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test assignment of ustack() to a dynamic variable (assoc element).
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + assoc["a"] = ustack(3);
> + printf("%k", assoc["a"]);
> +
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.asgn_dvar.r b/test/unittest/funcs/ustack/tst.asgn_dvar.r
> new file mode 100644
> index 00000000..2e9ba477
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_dvar.r
> @@ -0,0 +1 @@
> +success
> diff --git a/test/unittest/funcs/ustack/tst.asgn_dvar.r.p b/test/unittest/funcs/ustack/tst.asgn_dvar.r.p
> new file mode 100755
> index 00000000..0ffa73ba
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_dvar.r.p
> @@ -0,0 +1,60 @@
> +#!/usr/bin/gawk -f
> +
> +BEGIN {
> + cmd = "uname -rm";
> + cmd | getline;
> + close(cmd);
> +
> + if (/x86_64/) {
> + gsub(/\./, " ");
> + maj = int($1);
> + min = int($2);
> + if (maj < 6 || (maj == 6 && min < 11))
> + missing_frame = 1;
> + } else
> + missing_frame = 1;
> +}
> +
> +/myfunc_z/ {
> + # check probe
> + if ( $1 != "myfunc_z:entry" ) {
> + print "ERROR: expected fun:prb = myfunc_z:entry";
> + exit(0);
> + }
> +
> + # check stack(3)
> + getline;
> + if (index($1, "`myfunc_z+0x") == 0 &&
> + match($1, "`myfunc_z$") == 0) {
> + print "ERROR: expected leaf frame to be myfunc_z";
> + exit(0);
> + }
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing second frame";
> + exit(0);
> + }
> + if (index($1, missing_frame ? "`myfunc_x+0x" : "`myfunc_y+0x") == 0 &&
> + match($1, missing_frame ? "`myfunc_x$" : "`myfunc_y$") == 0) {
> + printf("ERROR: expected leaf frame to be %s\n", missing_frame ? "myfunc_x" : "myfunc_y");
> + exit(0);
> + }
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing third frame";
> + exit(0);
> + }
> + if (index($1, missing_frame ? "`myfunc_w+0x" : "`myfunc_x+0x") == 0 &&
> + match($1, missing_frame ? "`myfunc_w$" : "`myfunc_x$") == 0) {
> + printf("ERROR: expected leaf frame to be %s\n", missing_frame ? "myfunc_w" : "myfunc_x");
> + exit(0);
> + }
> + getline;
> + if (NF > 0) {
> + print "ERROR: expected stack(3) to have only three frames";
> + exit(0);
> + }
> +
> + print "success";
> + exit(0);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.asgn_gvar.d b/test/unittest/funcs/ustack/tst.asgn_gvar.d
> new file mode 100644
> index 00000000..089e145f
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_gvar.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test assignment of ustack() to a global variable.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + v = ustack(3);
> + printf("%k", v);
> +
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.asgn_gvar.r b/test/unittest/funcs/ustack/tst.asgn_gvar.r
> new file mode 120000
> index 00000000..a79e4237
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_gvar.r
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r
> \ No newline at end of file
> diff --git a/test/unittest/funcs/ustack/tst.asgn_gvar.r.p b/test/unittest/funcs/ustack/tst.asgn_gvar.r.p
> new file mode 120000
> index 00000000..2ca41971
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_gvar.r.p
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r.p
> \ No newline at end of file
> diff --git a/test/unittest/funcs/ustack/tst.asgn_lvar.d b/test/unittest/funcs/ustack/tst.asgn_lvar.d
> new file mode 100644
> index 00000000..132d4a89
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_lvar.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test assignment of ustack() to a local variable.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + this->v = ustack(3);
> + printf("%k", this->v);
> +
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.asgn_lvar.r b/test/unittest/funcs/ustack/tst.asgn_lvar.r
> new file mode 120000
> index 00000000..a79e4237
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_lvar.r
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r
> \ No newline at end of file
> diff --git a/test/unittest/funcs/ustack/tst.asgn_lvar.r.p b/test/unittest/funcs/ustack/tst.asgn_lvar.r.p
> new file mode 120000
> index 00000000..2ca41971
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_lvar.r.p
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r.p
> \ No newline at end of file
> diff --git a/test/unittest/funcs/ustack/tst.asgn_tvar.d b/test/unittest/funcs/ustack/tst.asgn_tvar.d
> new file mode 100644
> index 00000000..46fbe606
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_tvar.d
> @@ -0,0 +1,25 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test assignment of ustack() to a TLS variable.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + self->v = ustack(3);
> + printf("%k", self->v);
> +
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.asgn_tvar.r b/test/unittest/funcs/ustack/tst.asgn_tvar.r
> new file mode 120000
> index 00000000..a79e4237
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_tvar.r
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r
> \ No newline at end of file
> diff --git a/test/unittest/funcs/ustack/tst.asgn_tvar.r.p b/test/unittest/funcs/ustack/tst.asgn_tvar.r.p
> new file mode 120000
> index 00000000..2ca41971
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.asgn_tvar.r.p
> @@ -0,0 +1 @@
> +tst.asgn_dvar.r.p
> \ No newline at end of file
> diff --git a/test/unittest/funcs/ustack/tst.ref_addrs.d b/test/unittest/funcs/ustack/tst.ref_addrs.d
> new file mode 100644
> index 00000000..97b0d684
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_addrs.d
> @@ -0,0 +1,24 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'addrs' array of a userspace stack.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + trace("Expecting ustack-tst-basic`myfunc_z, got ");
> + ufunc(ustack(7).addrs[0]);
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.ref_addrs.r b/test/unittest/funcs/ustack/tst.ref_addrs.r
> new file mode 100644
> index 00000000..20f36969
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_addrs.r
> @@ -0,0 +1,5 @@
> + FUNCTION:NAME
> + myfunc_z:entry Expecting ustack-tst-basic`myfunc_z, got ustack-tst-basic`myfunc_z
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/ustack/tst.ref_addrs.d' matched 2 probes
> diff --git a/test/unittest/funcs/ustack/tst.ref_depth.d b/test/unittest/funcs/ustack/tst.ref_depth.d
> new file mode 100644
> index 00000000..d847736a
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_depth.d
> @@ -0,0 +1,35 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'depth' field of a userspace stack.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + trace("Expecting 7, got ");
> + trace(ustack(7).depth);
> +}
> +
> +pid$target:a.out:myfunc_z:entry
> +/ustack(7).depth == 7/
> +{
> + exit(0);
> +}
> +
> +pid$target:a.out:myfunc_z:entry
> +/ustack(7).depth != 7/
> +{
> + exit(1);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.ref_depth.r b/test/unittest/funcs/ustack/tst.ref_depth.r
> new file mode 100644
> index 00000000..de6bf067
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_depth.r
> @@ -0,0 +1,6 @@
> + FUNCTION:NAME
> + myfunc_z:entry Expecting 7, got 7
> + myfunc_z:entry
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/ustack/tst.ref_depth.d' matched 4 probes
> diff --git a/test/unittest/funcs/ustack/tst.ref_is_user.d b/test/unittest/funcs/ustack/tst.ref_is_user.d
> new file mode 100644
> index 00000000..5465f090
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_is_user.d
> @@ -0,0 +1,35 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'is_user' field of a userspace stack.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + trace("Expecting 1, got ");
> + trace(ustack(7).is_user);
> +}
> +
> +pid$target:a.out:myfunc_z:entry
> +/ustack(7).is_user == 1/
> +{
> + exit(0);
> +}
> +
> +pid$target:a.out:myfunc_z:entry
> +/ustack(7).is_user != 0/
> +{
> + exit(1);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.ref_is_user.r b/test/unittest/funcs/ustack/tst.ref_is_user.r
> new file mode 100644
> index 00000000..937fd8d3
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_is_user.r
> @@ -0,0 +1,6 @@
> + FUNCTION:NAME
> + myfunc_z:entry Expecting 1, got 1
> + myfunc_z:entry
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/ustack/tst.ref_is_user.d' matched 4 probes
> diff --git a/test/unittest/funcs/ustack/tst.ref_pid.d b/test/unittest/funcs/ustack/tst.ref_pid.d
> new file mode 100644
> index 00000000..80c2473b
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_pid.d
> @@ -0,0 +1,37 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'pid' field of a userspace stack.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + trace("Expecting ");
> + trace($target);
> + trace(", got ");
> + trace(ustack(7).pid);
> +}
> +
> +pid$target:a.out:myfunc_z:entry
> +/ustack(7).pid == $target/
> +{
> + exit(0);
> +}
> +
> +pid$target:a.out:myfunc_z:entry
> +/ustack(7).pid != $target/
> +{
> + exit(1);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.ref_strsz.d b/test/unittest/funcs/ustack/tst.ref_strsz.d
> new file mode 100644
> index 00000000..7d4740c3
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_strsz.d
> @@ -0,0 +1,35 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test accessing the 'strsz' field of a userspace stack.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + trace("Expecting 42, got ");
> + trace(ustack(7, 42).strsz);
> +}
> +
> +pid$target:a.out:myfunc_z:entry
> +/ustack(7, 42).strsz == 42/
> +{
> + exit(0);
> +}
> +
> +pid$target:a.out:myfunc_z:entry
> +/ustack(7, 42).strsz != 42/
> +{
> + exit(1);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.ref_strsz.r b/test/unittest/funcs/ustack/tst.ref_strsz.r
> new file mode 100644
> index 00000000..840f7e21
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.ref_strsz.r
> @@ -0,0 +1,6 @@
> + FUNCTION:NAME
> + myfunc_z:entry Expecting 42, got 42
> + myfunc_z:entry
> +
> +-- @@stderr --
> +dtrace: script 'test/unittest/funcs/ustack/tst.ref_strsz.d' matched 4 probes
> diff --git a/test/unittest/funcs/ustack/tst.store.d b/test/unittest/funcs/ustack/tst.store.d
> new file mode 100644
> index 00000000..066d5705
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.store.d
> @@ -0,0 +1,28 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: It is possible to store to members of dt_stack_t.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + v = ustack(5);
> + printf("%k", v);
> + v.depth = 2;
> + printf("%k", v);
> + v.depth = 5;
> + printf("%k", v);
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/funcs/ustack/tst.store.r b/test/unittest/funcs/ustack/tst.store.r
> new file mode 100644
> index 00000000..2e9ba477
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.store.r
> @@ -0,0 +1 @@
> +success
> diff --git a/test/unittest/funcs/ustack/tst.store.r.p b/test/unittest/funcs/ustack/tst.store.r.p
> new file mode 100755
> index 00000000..7ccffbb5
> --- /dev/null
> +++ b/test/unittest/funcs/ustack/tst.store.r.p
> @@ -0,0 +1,63 @@
> +#!/usr/bin/gawk -f
> +
> +/myfunc_z/ {
> + # check probe
> + if ( $1 != "myfunc_z:entry" ) {
> + print "ERROR: expected fun:prb = myfunc_z:entry";
> + exit(0);
> + }
> +
> + # collect 5 stack frames
> + for (i = 0; i < 5; i++) {
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing stack(5) frame addrs["i"]";
> + exit(0);
> + }
> + stack[i] = $0;
> + }
> + getline;
> + if (NF != 0) {
> + print "ERROR: too many stack frames (first stack(5))";
> + exit(0);
> + }
> +
> + # expect 2 stack frames
> + for (i = 0; i < 2; i++) {
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing stack(2) frame addrs["i"]";
> + exit(0);
> + }
> + if (stack[i] != $0) {
> + print "ERROR: wrong stack(2) frame addrs["i"]";
> + exit(0);
> + }
> + }
> + getline;
> + if (NF != 0) {
> + print "ERROR: too many stack frames (stack(2))";
> + exit(0);
> + }
> +
> + # expect 5 stack frames
> + for (i = 0; i < 5; i++) {
> + getline;
> + if (NF == 0) {
> + print "ERROR: missing stack(5) frame addrs["i"]";
> + exit(0);
> + }
> + if (stack[i] != $0) {
> + print "ERROR: wrong stack(5) frame addrs["i"]";
> + exit(0);
> + }
> + }
> + getline;
> + if (NF != 0) {
> + print "ERROR: too many stack frames (second stack(5))";
> + exit(0);
> + }
> +
> + print "success";
> + exit(0);
> +}
> diff --git a/test/unittest/printa/err.D_PRINTF_ARG_TYPE.stack.r b/test/unittest/printa/err.D_PRINTF_ARG_TYPE.stack.r
> index 95ac80da..b1e55bc0 100644
> --- a/test/unittest/printa/err.D_PRINTF_ARG_TYPE.stack.r
> +++ b/test/unittest/printa/err.D_PRINTF_ARG_TYPE.stack.r
> @@ -2,4 +2,4 @@
> dtrace: failed to compile script test/unittest/printa/err.D_PRINTF_ARG_TYPE.stack.d: [D_PRINTF_ARG_TYPE] line 12: printa( ) argument #2 is incompatible with conversion #1 prototype:
> conversion: %p
> prototype: pointer or integer
> - argument: dt_stack
> + argument: dt_stack_t
> diff --git a/test/unittest/printa/err.D_PRINTF_ARG_TYPE.ustack.r b/test/unittest/printa/err.D_PRINTF_ARG_TYPE.ustack.r
> index 5df10376..d6687d7a 100644
> --- a/test/unittest/printa/err.D_PRINTF_ARG_TYPE.ustack.r
> +++ b/test/unittest/printa/err.D_PRINTF_ARG_TYPE.ustack.r
> @@ -2,4 +2,4 @@
> dtrace: failed to compile script test/unittest/printa/err.D_PRINTF_ARG_TYPE.ustack.d: [D_PRINTF_ARG_TYPE] line 12: printa( ) argument #2 is incompatible with conversion #1 prototype:
> conversion: %p
> prototype: pointer or integer
> - argument: dt_stack
> + argument: dt_stack_t
> diff --git a/test/unittest/printf/tst.stack.d b/test/unittest/printf/tst.stack.d
> new file mode 100644
> index 00000000..db943c29
> --- /dev/null
> +++ b/test/unittest/printf/tst.stack.d
> @@ -0,0 +1,33 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/*
> + * ASSERTION: Test printf with %k and a stack argument.
> + *
> + * SECTION: Output Formatting/printf()
> + */
> +
> +#pragma D option destructive
> +
> +BEGIN
> +{
> + system("echo write something > /dev/null");
> +}
> +
> +fbt::ksys_write:entry
> +{
> + printf("%k", stack(1));
> + printf("%k", stack(2));
> + printf("%k", stack(3));
> + printf("%k", stack());
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/printf/tst.stack.r b/test/unittest/printf/tst.stack.r
> new file mode 100644
> index 00000000..2e9ba477
> --- /dev/null
> +++ b/test/unittest/printf/tst.stack.r
> @@ -0,0 +1 @@
> +success
> diff --git a/test/unittest/printf/tst.stack.r.p b/test/unittest/printf/tst.stack.r.p
> new file mode 100755
> index 00000000..895f96f5
> --- /dev/null
> +++ b/test/unittest/printf/tst.stack.r.p
> @@ -0,0 +1,75 @@
> +#!/usr/bin/gawk -f
> +
> +/ksys_write/ {
> + # check probe
> + if ( $1 != "ksys_write:entry" ) {
> + print "ERROR: expected fun:prb = ksys_write:entry";
> + exit 1;
> + }
> +
> + # check stack(1)
> + getline;
> + if (index($1, "`ksys_write+0x") == 0 &&
> + match($1, "`ksys_write$") == 0) {
> + print "ERROR: expected leaf frame to be ksys_write";
> + exit 1;
> + }
> + FRAME1 = $1;
> + getline;
> + if (NF > 0) {
> + print "ERROR: expected stack(1) to have only one frame";
> + exit 1;
> + }
> +
> + # check stack(2)
> + getline;
> + if ($1 != FRAME1) {
> + print "ERROR: stack(2) leaf frame looks wrong";
> + exit 1;
> + }
> + getline;
> + FRAME2 = $1;
> + getline;
> + if (NF > 0) {
> + print "ERROR: expected stack(2) to have only two frames";
> + exit 1;
> + }
> +
> + # check stack(3)
> + getline;
> + if ($1 != FRAME1) {
> + print "ERROR: stack(3) leaf frame looks wrong";
> + exit 1;
> + }
> + getline;
> + if ($1 != FRAME2) {
> + print "ERROR: stack(3) frame2 looks wrong";
> + exit 1;
> + }
> + getline;
> + FRAME3 = $1;
> + getline;
> + if (NF > 0) {
> + print "ERROR: expected stack(3) to have only three frames";
> + exit 1;
> + }
> +
> + # check stack()
> + getline;
> + if ($1 != FRAME1) {
> + print "ERROR: stack() leaf frame looks wrong";
> + exit 1;
> + }
> + getline;
> + if ($1 != FRAME2) {
> + print "ERROR: stack() frame2 looks wrong";
> + exit 1;
> + }
> + getline;
> + if ($1 != FRAME3) {
> + print "ERROR: stack() frame3 looks wrong";
> + exit 1;
> + }
> + print "success";
> + exit(0);
> +}
> diff --git a/test/unittest/printf/tst.ustack25_pid.d b/test/unittest/printf/tst.ustack25_pid.d
> new file mode 100644
> index 00000000..9ae3a7b8
> --- /dev/null
> +++ b/test/unittest/printf/tst.ustack25_pid.d
> @@ -0,0 +1,21 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +/* @@trigger: ustack-tst-basic */
> +
> +#pragma D option quiet
> +
> +pid$target:a.out:myfunc_z:entry
> +{
> + printf("%k", ustack(25));
> + exit(0);
> +}
> +
> +ERROR
> +{
> + exit(1);
> +}
> diff --git a/test/unittest/printf/tst.ustack25_pid.r b/test/unittest/printf/tst.ustack25_pid.r
> new file mode 100644
> index 00000000..412df410
> --- /dev/null
> +++ b/test/unittest/printf/tst.ustack25_pid.r
> @@ -0,0 +1,28 @@
> +
> +ustack-tst-basic`myfunc_z
> +ustack-tst-basic`myfunc_y+{ptr}
> +ustack-tst-basic`myfunc_x+{ptr}
> +ustack-tst-basic`myfunc_w+{ptr}
> +ustack-tst-basic`myfunc_v+{ptr}
> +ustack-tst-basic`myfunc_u+{ptr}
> +ustack-tst-basic`myfunc_t+{ptr}
> +ustack-tst-basic`myfunc_s+{ptr}
> +ustack-tst-basic`myfunc_r+{ptr}
> +ustack-tst-basic`myfunc_q+{ptr}
> +ustack-tst-basic`myfunc_p+{ptr}
> +ustack-tst-basic`myfunc_o+{ptr}
> +ustack-tst-basic`myfunc_n+{ptr}
> +ustack-tst-basic`myfunc_m+{ptr}
> +ustack-tst-basic`myfunc_l+{ptr}
> +ustack-tst-basic`myfunc_k+{ptr}
> +ustack-tst-basic`myfunc_j+{ptr}
> +ustack-tst-basic`myfunc_i+{ptr}
> +ustack-tst-basic`myfunc_h+{ptr}
> +ustack-tst-basic`myfunc_g+{ptr}
> +ustack-tst-basic`myfunc_f+{ptr}
> +ustack-tst-basic`myfunc_e+{ptr}
> +ustack-tst-basic`myfunc_d+{ptr}
> +ustack-tst-basic`myfunc_c+{ptr}
> +ustack-tst-basic`myfunc_b+{ptr}
> +ustack-tst-basic`myfunc_a+{ptr}
> +
> diff --git a/test/unittest/printf/tst.ustack25_pid.r.p b/test/unittest/printf/tst.ustack25_pid.r.p
> new file mode 100755
> index 00000000..c87ef73f
> --- /dev/null
> +++ b/test/unittest/printf/tst.ustack25_pid.r.p
> @@ -0,0 +1,37 @@
> +#!/bin/bash
> +
> +# A pid entry probe places a uprobe on the first instruction of a function.
> +# Unfortunately, this is so early in the function preamble that the function
> +# frame pointer has not yet been established and the actual caller of the
> +# traced function is missed.
> +#
> +# In Linux 6.11, x86-specific heuristics are introduced to fix this problem.
> +# See commit cfa7f3d
> +# ("perf,x86: avoid missing caller address in stack traces captured in uprobe")
> +# for both a description of the problem and an explanation of the heuristics.
> +#
> +# Add post processing to these test results to allow for both cases:
> +# caller frame is missing or not missing.
> +
> +missing_caller=1
> +if [ $(uname -m) == "x86_64" ]; then
> + read MAJOR MINOR <<< `uname -r | grep -Eo '^[0-9]+\.[0-9]+' | tr '.' ' '`
> +
> + if [ $MAJOR -ge 6 ]; then
> + if [ $MAJOR -gt 6 -o $MINOR -ge 11 ]; then
> + missing_caller=0
> + fi
> + fi
> +fi
> +
> +if [ $missing_caller -eq 1 ]; then
> + # Add the missing caller function after the current function.
> + awk '{ print }
> + /myfunc_z/ { print "ustack-tst-basic`myfunc_y+{ptr}" }'
> +else
> + # The .r results file has an extra frame at the end in case
> + # the caller frame is missing and the 25-frame limit goes
> + # "too far." If the caller is not missing, fake that extra frame.
> + awk '{ print }
> + /myfunc_b/ { print "ustack-tst-basic`myfunc_a+{ptr}" }'
> +fi
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