PR12124 Emit warnings for bad unwind data encountered at runtime.

* runtime/unwind.c: Turn dbug_unwind into _stp_warn when they indicate
  bad unwind data in binary.

diff --git a/runtime/unwind.c b/runtime/unwind.c
index b1432fdd06845cdd57a760871735ab49926c9c9b..ef7ff00d1a2d9f232a300a523992e4bb82104b95 100644 (file)
--- a/runtime/unwind.c
+++ b/runtime/unwind.c
@@ -106,7 +106,7 @@ static const u32 *cie_for_fde(const u32 *fde, void *unwind_data,
 
        /* CIE_pointer must be a proper offset */
        if ((fde[1] & (sizeof(*fde) - 1)) || fde[1] > (unsigned long)(fde + 1) - (unsigned long)unwind_data) {
-               dbug_unwind(1, "fde[1]=%lx fde+1=%lx, unwind_data=%lx  %lx\n",
+               _stp_warn("invalid fde[1]=%lx fde+1=%lx, unwind_data=%lx  %lx\n",
                            (unsigned long)fde[1], (unsigned long)(fde + 1),
                            (unsigned long)unwind_data, (unsigned long)(fde + 1) - (unsigned long)unwind_data);
                return NULL;    /* this is not a valid FDE */
@@ -126,7 +126,7 @@ static const u32 *cie_for_fde(const u32 *fde, void *unwind_data,
        if (*cie <= sizeof(*cie) + 4 || *cie >= fde[1] - sizeof(*fde)
            || (*cie & (sizeof(*cie) - 1))
            || (cie[1] != 0xffffffff && cie[1] != 0)) {
-               dbug_unwind(1, "cie is not valid %lx %x %x %x\n", (unsigned long)cie, *cie, fde[1], cie[1]);
+               _stp_warn("cie is not valid %lx %x %x %x\n", (unsigned long)cie, *cie, fde[1], cie[1]);
                return NULL;    /* this is not a (valid) CIE */
        }
 
@@ -455,7 +455,7 @@ static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc, s
                                        dbug_unwind(1, "DW_CFA_def_cfa_expression %lu@%p\n", value, cfa_expr);
                                }
                                else
-                                       dbug_unwind(1, "DW_CFA_def_cfa_expression BAD %lu\n", value);
+                                       _stp_warn("BAD DW_CFA_def_cfa_expression value %lu\n", value);
                                break;
                        }
                        case DW_CFA_GNU_args_size:
@@ -469,7 +469,7 @@ static int processCFI(const u8 *start, const u8 *end, unsigned long targetLoc, s
                                break;
                        case DW_CFA_GNU_window_save:
                        default:
-                               dbug_unwind(1, "unimplemented call frame instruction: 0x%x\n", *(ptr.p8 - 1));
+                               _stp_warn("unimplemented call frame instruction: 0x%x\n", *(ptr.p8 - 1));
                                result = 0;
                                break;
                        }
@@ -620,7 +620,7 @@ static u32 *_stp_search_unwind_hdr(unsigned long pc, struct task_struct *tsk,
                tableSize = 8;
                break;
        default:
-               dbug_unwind(1, "bad table encoding");
+               _stp_warn("bad unwind table encoding");
                return NULL;
        }
        ptr = hdr + 4;
@@ -632,14 +632,14 @@ static u32 *_stp_search_unwind_hdr(unsigned long pc, struct task_struct *tsk,
                if ((hdr[1] & DW_EH_PE_ADJUST) == DW_EH_PE_pcrel)
                        eh = eh - (unsigned long)hdr + eh_hdr_addr;
                if ((is_ehframe && eh != (unsigned long)m->eh_frame_addr)) {
-                       dbug_unwind(1, "eh_frame_ptr in eh_frame_hdr 0x%lx not valid; eh_frame_addr = 0x%lx", eh, (unsigned long)m->eh_frame_addr);
+                       _stp_warn("eh_frame_ptr in eh_frame_hdr 0x%lx not valid; eh_frame_addr = 0x%lx", eh, (unsigned long)m->eh_frame_addr);
                        return NULL;
                }
        }
        num = read_ptr_sect(&ptr, end, hdr[2], 0, eh_hdr_addr);
        if (num == 0 || num != (end - ptr) / (2 * tableSize)
            || (end - ptr) % (2 * tableSize)) {
-               dbug_unwind(1, "Bad num=%d end-ptr=%ld 2*tableSize=%d",
+               _stp_warn("unwind Bad num=%d end-ptr=%ld 2*tableSize=%d",
                            num, (long)(end - ptr), 2 * tableSize);
                return NULL;
        }
@@ -743,7 +743,7 @@ static int compute_expr(const u8 *expr, struct unwind_frame_info *frame,
                        if (u.s16 < 0 ?
                            unlikely(expr - start < -u.s16) :
                            unlikely(end - expr < u.s16)) {
-                               dbug_unwind(1, "invalid skip %d in CFI expression\n", (int) u.s16);
+                               _stp_warn("invalid skip %d in CFI expression\n", (int) u.s16);
                                return 1;
                        }
                        /*
@@ -751,7 +751,7 @@ static int compute_expr(const u8 *expr, struct unwind_frame_info *frame,
                         * So punt it until we find we actually need it.
                         */
                        if (u.s16 < 0) {
-                               dbug_unwind(1, "backward branch in CFI expression not supported\n");
+                               _stp_warn("backward branch in CFI expression not supported\n");
                                return 1;
                        }
                        expr += u.s16;
@@ -882,7 +882,7 @@ static int compute_expr(const u8 *expr, struct unwind_frame_info *frame,
                        value = op - DW_OP_breg0;
                breg:
                        if (unlikely(value >= ARRAY_SIZE(reg_info))) {
-                               dbug_unwind(1, "invalid register number %lu in CFI expression\n", value);
+                               _stp_warn("invalid register number %lu in CFI expression\n", value);
                                return 1;
                        } else {
                                sleb128_t offset = get_sleb128(&expr, end);
@@ -899,7 +899,7 @@ static int compute_expr(const u8 *expr, struct unwind_frame_info *frame,
                        value = *expr++;
                        if (unlikely(value > sizeof(stack[0]))) {
                        bad_deref_size:
-                               dbug_unwind(1, "invalid DW_OP_deref_size %lu in CFI expression\n", value);
+                               _stp_warn("invalid DW_OP_deref_size %lu in CFI expression\n", value);
                                return 1;
                        }
                deref: {
@@ -919,7 +919,7 @@ static int compute_expr(const u8 *expr, struct unwind_frame_info *frame,
 
                case DW_OP_rot:
                default:
-                       dbug_unwind(1, "unimplemented CFI expression operation: 0x%x\n", op);
+                       _stp_warn("unimplemented CFI expression operation: 0x%x\n", op);
                        return 1;
                }
        }
@@ -928,16 +928,16 @@ static int compute_expr(const u8 *expr, struct unwind_frame_info *frame,
        return 0;
 
 copy_failed:
-       dbug_unwind(1, "_stp_read_address failed to access memory\n");
+       _stp_warn("_stp_read_address failed to access memory\n");
        return 1;
 truncated:
-       dbug_unwind(1, "invalid (truncated) DWARF expression in CFI\n");
+       _stp_warn("invalid (truncated) DWARF expression in CFI\n");
        return 1;
 overflow:
-       dbug_unwind(1, "DWARF expression stack overflow in CFI\n");
+       _stp_warn("DWARF expression stack overflow in CFI\n");
        return 1;
 underflow:
-       dbug_unwind(1, "DWARF expression stack underflow in CFI\n");
+       _stp_warn("DWARF expression stack underflow in CFI\n");
        return 1;
 
 #undef NEED
@@ -963,8 +963,14 @@ static int unwind_frame(struct unwind_frame_info *frame,
        struct unwind_state state;
        unsigned long addr;
 
-       if (unlikely(table_len == 0 || table_len & (sizeof(*fde) - 1))) {
-               dbug_unwind(1, "Module %s: frame_len=%d", m->name, table_len);
+       if (unlikely(table_len == 0)) {
+               // Don't _stp_warn about this, debug_frame and/or eh_frame
+               // might actually not be there.
+               dbug_unwind(1, "Module %s: no unwind frame data", m->name);
+               goto err;
+       }
+       if (unlikely(table_len & (sizeof(*fde) - 1))) {
+               _stp_warn("Module %s: frame_len=%d", m->name, table_len);
                goto err;
        }
 
@@ -986,11 +992,11 @@ static int unwind_frame(struct unwind_frame_info *frame,
                                ptrType &= DW_EH_PE_FORM | DW_EH_PE_signed;
                        endLoc = startLoc + read_pointer(&ptr, (const u8 *)(fde + 1) + *fde, ptrType);
                        if (pc > endLoc) {
-                               dbug_unwind(1, "pc (%lx) > endLoc(%lx)\n", pc, endLoc);
+                               _stp_warn("pc (%lx) > endLoc(%lx)\n", pc, endLoc);
                                goto done;
                        }
                } else {
-                       dbug_unwind(1, "fde found in header, but cie is bad!\n");
+                       _stp_warn("fde found in header, but cie is bad!\n");
                        fde = NULL;
                }
        }
@@ -1043,7 +1049,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
        frame->call_frame = 1;
        state.version = *ptr;
        if (state.version != 1 && state.version != 3 && state.version != 4) {
-               dbug_unwind(1, "CIE version number is %d.  1, 3 or 4 is supported.\n", state.version);
+               _stp_warn("CIE version number is %d.  1, 3 or 4 is supported.\n", state.version);
                goto err;       /* unsupported version */
        }
        if (*++ptr) {
@@ -1068,7 +1074,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
                        }
                }
                if (ptr >= end || *ptr) {
-                       dbug_unwind(1, "Problem parsing the augmentation string.\n");
+                       _stp_warn("Problem parsing the augmentation string.\n");
                        goto err;
                }
        }
@@ -1144,7 +1150,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
                if (REG_INVALID(i)) {
                        if (state.regs[i].where == Nowhere)
                                continue;
-                       dbug_unwind(2, "REG_INVALID %d\n", i);
+                       _stp_warn("REG_INVALID %d\n", i);
                        goto err;
                }
                dbug_unwind(2, "register %d. where=%d\n", i, state.regs[i].where);
@@ -1155,7 +1161,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
                        if (state.regs[i].value >= ARRAY_SIZE(reg_info)
                            || REG_INVALID(state.regs[i].value)
                            || reg_info[i].width > reg_info[state.regs[i].value].width) {
-                               dbug_unwind(2, "case Register bad\n");
+                               _stp_warn("case Register bad\n");
                                goto err;
                        }
                        switch (reg_info[state.regs[i].value].width) {
@@ -1167,7 +1173,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
                                CASES;
 #undef CASE
                        default:
-                               dbug_unwind(2, "default\n");
+                               _stp_warn("bad Register size\n");
                                goto err;
                        }
                        break;
@@ -1194,7 +1200,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
                                CASES;
 #undef CASE
                        default:
-                               dbug_unwind(2, "default\n");
+                               _stp_warn("bad Register size\n");
                                goto err;
                        }
                        break;
@@ -1210,7 +1216,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
                        addr = cfa + state.regs[i].value * state.dataAlign;
                value:
                        if (reg_info[i].width != sizeof(unsigned long)) {
-                               dbug_unwind(2, "Value\n");
+                               _stp_warn("bad Register width\n");
                                goto err;
                        }
                        FRAME_REG(i, unsigned long) = addr;
@@ -1228,7 +1234,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
                                CASES;
 #undef CASE
                        default:
-                               dbug_unwind(2, "default\n");
+                               _stp_warn("bad Register width\n");
                                goto err;
                        }
                        break;
@@ -1238,7 +1244,7 @@ static int unwind_frame(struct unwind_frame_info *frame,
        return 0;
 
 copy_failed:
-       dbug_unwind(1, "_stp_read_address failed to access memory\n");
+       _stp_warn("_stp_read_address failed to access memory\n");
 err:
        return -EIO;
 
@@ -1273,6 +1279,7 @@ static int unwind(struct unwind_frame_info *frame, struct task_struct *tsk)
          m = _stp_kmod_sec_lookup (pc, &s);
 
        if (unlikely(m == NULL)) {
+               // Don't _stp_warn about this, will use fallback unwinder.
                dbug_unwind(1, "No module found for pc=%lx", pc);
                return -EINVAL;
        }