diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 3 | ||||
| -rw-r--r-- | kernel/unwind.c | 113 |
2 files changed, 99 insertions, 17 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 4e90aa427aea..d34fd6a28faa 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1735,6 +1735,9 @@ and is between 256 and 4096 characters. It is defined in the file norandmaps Don't use address space randomization Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space + unwind_debug=N N > 0 will enable dwarf2 unwinder debugging + This is useful to get more information why + you got a "dwarf2 unwinder stuck" ______________________________________________________________________ diff --git a/kernel/unwind.c b/kernel/unwind.c index 7e721f104105..209e248517db 100644 --- a/kernel/unwind.c +++ b/kernel/unwind.c @@ -137,6 +137,17 @@ struct unwind_state { static const struct cfa badCFA = { ARRAY_SIZE(reg_info), 1 }; +static unsigned unwind_debug; +static int __init unwind_debug_setup(char *s) +{ + unwind_debug = simple_strtoul(s, NULL, 0); + return 1; +} +__setup("unwind_debug=", unwind_debug_setup); +#define dprintk(lvl, fmt, args...) \ + ((void)(lvl > unwind_debug \ + || printk(KERN_DEBUG "unwind: " fmt "\n", ##args))) + static struct unwind_table *find_table(unsigned long pc) { struct unwind_table *table; @@ -281,6 +292,7 @@ static void __init setup_unwind_table(struct unwind_table *table, hdrSize = 4 + sizeof(unsigned long) + sizeof(unsigned int) + 2 * n * sizeof(unsigned long); + dprintk(2, "Binary lookup table size for %s: %lu bytes", table->name, hdrSize); header = alloc(hdrSize); if (!header) return; @@ -500,13 +512,17 @@ static unsigned long read_pointer(const u8 **pLoc, const unsigned long *pul; } ptr; - if (ptrType < 0 || ptrType == DW_EH_PE_omit) + if (ptrType < 0 || ptrType == DW_EH_PE_omit) { + dprintk(1, "Invalid pointer encoding %02X (%p,%p).", ptrType, *pLoc, end); return 0; + } ptr.p8 = *pLoc; switch(ptrType & DW_EH_PE_FORM) { case DW_EH_PE_data2: - if (end < (const void *)(ptr.p16u + 1)) + if (end < (const void *)(ptr.p16u + 1)) { + dprintk(1, "Data16 overrun (%p,%p).", ptr.p8, end); return 0; + } if(ptrType & DW_EH_PE_signed) value = get_unaligned(ptr.p16s++); else @@ -514,8 +530,10 @@ static unsigned long read_pointer(const u8 **pLoc, break; case DW_EH_PE_data4: #ifdef CONFIG_64BIT - if (end < (const void *)(ptr.p32u + 1)) + if (end < (const void *)(ptr.p32u + 1)) { + dprintk(1, "Data32 overrun (%p,%p).", ptr.p8, end); return 0; + } if(ptrType & DW_EH_PE_signed) value = get_unaligned(ptr.p32s++); else @@ -527,8 +545,10 @@ static unsigned long read_pointer(const u8 **pLoc, BUILD_BUG_ON(sizeof(u32) != sizeof(value)); #endif case DW_EH_PE_native: - if (end < (const void *)(ptr.pul + 1)) + if (end < (const void *)(ptr.pul + 1)) { + dprintk(1, "DataUL overrun (%p,%p).", ptr.p8, end); return 0; + } value = get_unaligned(ptr.pul++); break; case DW_EH_PE_leb128: @@ -536,10 +556,14 @@ static unsigned long read_pointer(const u8 **pLoc, value = ptrType & DW_EH_PE_signed ? get_sleb128(&ptr.p8, end) : get_uleb128(&ptr.p8, end); - if ((const void *)ptr.p8 > end) + if ((const void *)ptr.p8 > end) { + dprintk(1, "DataLEB overrun (%p,%p).", ptr.p8, end); return 0; + } break; default: + dprintk(2, "Cannot decode pointer type %02X (%p,%p).", + ptrType, ptr.p8, end); return 0; } switch(ptrType & DW_EH_PE_ADJUST) { @@ -549,11 +573,16 @@ static unsigned long read_pointer(const u8 **pLoc, value += (unsigned long)*pLoc; break; default: + dprintk(2, "Cannot adjust pointer type %02X (%p,%p).", + ptrType, *pLoc, end); return 0; } if ((ptrType & DW_EH_PE_indirect) - && probe_kernel_address((unsigned long *)value, value)) + && probe_kernel_address((unsigned long *)value, value)) { + dprintk(1, "Cannot read indirect value %lx (%p,%p).", + value, *pLoc, end); return 0; + } *pLoc = ptr.p8; return value; @@ -702,8 +731,10 @@ static int processCFI(const u8 *start, state->label = NULL; return 1; } - if (state->stackDepth >= MAX_STACK_DEPTH) + if (state->stackDepth >= MAX_STACK_DEPTH) { + dprintk(1, "State stack overflow (%p,%p).", ptr.p8, end); return 0; + } state->stack[state->stackDepth++] = ptr.p8; break; case DW_CFA_restore_state: @@ -718,8 +749,10 @@ static int processCFI(const u8 *start, result = processCFI(start, end, 0, ptrType, state); state->loc = loc; state->label = label; - } else + } else { + dprintk(1, "State stack underflow (%p,%p).", ptr.p8, end); return 0; + } break; case DW_CFA_def_cfa: state->cfa.reg = get_uleb128(&ptr.p8, end); @@ -751,6 +784,7 @@ static int processCFI(const u8 *start, break; case DW_CFA_GNU_window_save: default: + dprintk(1, "Unrecognized CFI op %02X (%p,%p).", ptr.p8[-1], ptr.p8 - 1, end); result = 0; break; } @@ -766,12 +800,17 @@ static int processCFI(const u8 *start, set_rule(*ptr.p8++ & 0x3f, Nowhere, 0, state); break; } - if (ptr.p8 > end) + if (ptr.p8 > end) { + dprintk(1, "Data overrun (%p,%p).", ptr.p8, end); result = 0; + } if (result && targetLoc != 0 && targetLoc < state->loc) return 1; } + if (result && ptr.p8 < end) + dprintk(1, "Data underrun (%p,%p).", ptr.p8, end); + return result && ptr.p8 == end && (targetLoc == 0 @@ -843,6 +882,8 @@ int unwind(struct unwind_frame_info *frame) hdr[3]); } } + if(hdr && !fde) + dprintk(3, "Binary lookup for %lx failed.", pc); if (fde != NULL) { cie = cie_for_fde(fde, table); @@ -864,6 +905,8 @@ int unwind(struct unwind_frame_info *frame) fde = NULL; } else fde = NULL; + if(!fde) + dprintk(1, "Binary lookup result for %lx discarded.", pc); } if (fde == NULL) { for (fde = table->address, tableSize = table->size; @@ -895,6 +938,8 @@ int unwind(struct unwind_frame_info *frame) if (pc >= startLoc && pc < endLoc) break; } + if(!fde) + dprintk(3, "Linear lookup for %lx failed.", pc); } } if (cie != NULL) { @@ -928,6 +973,8 @@ int unwind(struct unwind_frame_info *frame) if (ptr >= end || *ptr) cie = NULL; } + if(!cie) + dprintk(1, "CIE unusable (%p,%p).", ptr, end); ++ptr; } if (cie != NULL) { @@ -938,9 +985,11 @@ int unwind(struct unwind_frame_info *frame) if (state.codeAlign == 0 || state.dataAlign == 0 || ptr >= end) cie = NULL; else if (UNW_PC(frame) % state.codeAlign - || UNW_SP(frame) % sleb128abs(state.dataAlign)) + || UNW_SP(frame) % sleb128abs(state.dataAlign)) { + dprintk(1, "Input pointer(s) misaligned (%lx,%lx).", + UNW_PC(frame), UNW_SP(frame)); return -EPERM; - else { + } else { retAddrReg = state.version <= 1 ? *ptr++ : get_uleb128(&ptr, end); /* skip augmentation */ if (((const char *)(cie + 2))[1] == 'z') { @@ -954,6 +1003,8 @@ int unwind(struct unwind_frame_info *frame) || reg_info[retAddrReg].width != sizeof(unsigned long)) cie = NULL; } + if(!cie) + dprintk(1, "CIE validation failed (%p,%p).", ptr, end); } if (cie != NULL) { state.cieStart = ptr; @@ -967,6 +1018,8 @@ int unwind(struct unwind_frame_info *frame) if ((ptr += augSize) > end) fde = NULL; } + if(!fde) + dprintk(1, "FDE validation failed (%p,%p).", ptr, end); } if (cie == NULL || fde == NULL) { #ifdef CONFIG_FRAME_POINTER @@ -1025,8 +1078,10 @@ int unwind(struct unwind_frame_info *frame) || state.cfa.reg >= ARRAY_SIZE(reg_info) || reg_info[state.cfa.reg].width != sizeof(unsigned long) || FRAME_REG(state.cfa.reg, unsigned long) % sizeof(unsigned long) - || state.cfa.offs % sizeof(unsigned long)) + || state.cfa.offs % sizeof(unsigned long)) { + dprintk(1, "Unusable unwind info (%p,%p).", ptr, end); return -EIO; + } /* update frame */ #ifndef CONFIG_AS_CFI_SIGNAL_FRAME if(frame->call_frame @@ -1051,6 +1106,8 @@ int unwind(struct unwind_frame_info *frame) if (REG_INVALID(i)) { if (state.regs[i].where == Nowhere) continue; + dprintk(1, "Cannot restore register %u (%d).", + i, state.regs[i].where); return -EIO; } switch(state.regs[i].where) { @@ -1059,8 +1116,11 @@ int unwind(struct unwind_frame_info *frame) case Register: 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) + || reg_info[i].width > reg_info[state.regs[i].value].width) { + dprintk(1, "Cannot restore register %u from register %lu.", + i, state.regs[i].value); return -EIO; + } switch(reg_info[state.regs[i].value].width) { #define CASE(n) \ case sizeof(u##n): \ @@ -1070,6 +1130,9 @@ int unwind(struct unwind_frame_info *frame) CASES; #undef CASE default: + dprintk(1, "Unsupported register size %u (%lu).", + reg_info[state.regs[i].value].width, + state.regs[i].value); return -EIO; } break; @@ -1094,12 +1157,17 @@ int unwind(struct unwind_frame_info *frame) CASES; #undef CASE default: + dprintk(1, "Unsupported register size %u (%u).", + reg_info[i].width, i); return -EIO; } break; case Value: - if (reg_info[i].width != sizeof(unsigned long)) + if (reg_info[i].width != sizeof(unsigned long)) { + dprintk(1, "Unsupported value size %u (%u).", + reg_info[i].width, i); return -EIO; + } FRAME_REG(i, unsigned long) = cfa + state.regs[i].value * state.dataAlign; break; @@ -1111,8 +1179,11 @@ int unwind(struct unwind_frame_info *frame) % sizeof(unsigned long) || addr < startLoc || addr + sizeof(unsigned long) < addr - || addr + sizeof(unsigned long) > endLoc) + || addr + sizeof(unsigned long) > endLoc) { + dprintk(1, "Bad memory location %lx (%lx).", + addr, state.regs[i].value); return -EIO; + } switch(reg_info[i].width) { #define CASE(n) case sizeof(u##n): \ probe_kernel_address((u##n *)addr, FRAME_REG(i, u##n)); \ @@ -1120,6 +1191,8 @@ int unwind(struct unwind_frame_info *frame) CASES; #undef CASE default: + dprintk(1, "Unsupported memory size %u (%u).", + reg_info[i].width, i); return -EIO; } } @@ -1128,9 +1201,15 @@ int unwind(struct unwind_frame_info *frame) } if (UNW_PC(frame) % state.codeAlign - || UNW_SP(frame) % sleb128abs(state.dataAlign) - || (pc == UNW_PC(frame) && sp == UNW_SP(frame))) + || UNW_SP(frame) % sleb128abs(state.dataAlign)) { + dprintk(1, "Output pointer(s) misaligned (%lx,%lx).", + UNW_PC(frame), UNW_SP(frame)); return -EIO; + } + if (pc == UNW_PC(frame) && sp == UNW_SP(frame)) { + dprintk(1, "No progress (%lx,%lx).", pc, sp); + return -EIO; + } return 0; #undef CASES |