diff options
| -rw-r--r-- | translate.cxx | 45 |
1 files changed, 29 insertions, 16 deletions
diff --git a/translate.cxx b/translate.cxx index 3442703d..a22e9a5b 100644 --- a/translate.cxx +++ b/translate.cxx @@ -4486,7 +4486,7 @@ dump_unwindsyms (Dwfl_Module *m, // In the future, we'll also care about data symbols. int syments = dwfl_module_getsymtab(m); - assert(syments); + dwfl_assert ("Getting symbol table for " + modname, syments >= 0); //extract build-id from debuginfo file int build_id_len = 0; @@ -4532,6 +4532,10 @@ dump_unwindsyms (Dwfl_Module *m, } } + // Use end as sanity check when resolving symbol addresses. + Dwarf_Addr end; + dwfl_module_info (m, NULL, NULL, &end, NULL, NULL, NULL, NULL); + // Look up the relocation basis for symbols int n = dwfl_module_relocations (m); @@ -4546,10 +4550,11 @@ dump_unwindsyms (Dwfl_Module *m, Dwarf_Addr extra_offset = 0; - for (int i = 1 /* XXX: why not 0? */ ; i < syments; ++i) + for (int i = 0; i < syments; ++i) { GElf_Sym sym; - const char *name = dwfl_module_getsym(m, i, &sym, NULL); + GElf_Word shndxp; + const char *name = dwfl_module_getsym(m, i, &sym, &shndxp); if (name) { // NB: Yey, we found the kernel's _stext value. @@ -4572,17 +4577,15 @@ dump_unwindsyms (Dwfl_Module *m, clog << "Found kernel _stext extra offset 0x" << hex << extra_offset << dec << endl; } - // We only need the function symbols to identify kernel-mode - // PC's, so we omit undefined or "fake" absolute addresses. - // These fake absolute addresses occur in some older i386 - // kernels to indicate they are vDSO symbols, not real - // functions in the kernel. We also omit symbols that have - // suspicious addresses (before base). + // We are only interested in "real" symbols. + // We omit symbols that have suspicious addresses (before base, + // or after end). if ((GELF_ST_TYPE (sym.st_info) == STT_FUNC || GELF_ST_TYPE (sym.st_info) == STT_OBJECT) // PR10000: also need .data - && !(sym.st_shndx == SHN_UNDEF - || sym.st_shndx == SHN_ABS - || sym.st_value < base)) + && !(sym.st_shndx == SHN_UNDEF // Value undefined, + || shndxp == (GElf_Word) -1 // in a non-allocated section, + || sym.st_value >= end // beyond current module, + || sym.st_value < base)) // before first section. { Dwarf_Addr sym_addr = sym.st_value; const char *secname = NULL; @@ -4607,6 +4610,16 @@ dump_unwindsyms (Dwfl_Module *m, { // This is a symbol within a (possibly relocatable) // kernel image. + + // We only need the function symbols to identify kernel-mode + // PC's, so we omit undefined or "fake" absolute addresses. + // These fake absolute addresses occur in some older i386 + // kernels to indicate they are vDSO symbols, not real + // functions in the kernel. We also omit symbols that have + if (GELF_ST_TYPE (sym.st_info) == STT_FUNC + && sym.st_shndx == SHN_ABS) + continue; + secname = "_stext"; // NB: don't subtract session.sym_stext, which could be inconveniently NULL. // Instead, sym_addr will get compensated later via extra_offset. @@ -4666,10 +4679,10 @@ dump_unwindsyms (Dwfl_Module *m, // There would be only a small benefit to warning. A user // likely can't do anything about this; backtraces for the // affected module would just get all icky heuristicy. -#if 0 - c->session.print_warning ("No unwind data for " + modname - + ", " + dwfl_errmsg (-1)); -#endif + // So only report in verbose mode. + if (c->session.verbose > 2) + c->session.print_warning ("No unwind data for " + modname + + ", " + dwfl_errmsg (-1)); } for (unsigned secidx = 0; secidx < seclist.size(); secidx++) |