| Re: [tcf-dev] Continue if invalid public symbol object offset |
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Hi Claes, If the section is corrupted, it would be best to skip loading the whole section, not just some of the entries. debug_pubnames section is optional, so the debugger will work OK without loading it. Could you create a Bugzilla and attach the ELF file as the test case? Thanks, Eugene From: tcf-dev-bounces@xxxxxxxxxxx [mailto:tcf-dev-bounces@xxxxxxxxxxx]
On Behalf Of Lillieskold, Claes Hi, I investigate a debugging problem where it seems that some entries in .debug_pubnames have faulty offsets. Not sure why, but it seems that the debug information (C++, the compiler is Clang 3.5.2) is broken The current code for handling this throws an exception (dwarfcache.c): if (obj_offs >= unit_size) str_fmt_exception(ERR_INV_DWARF, "Invalid object offset in %s section", pub_names->name); For other errors, however the iteration of pubnames simply continues, and the current pubname is ignored. In my binary, the pubname string is valid (and non-empty). I wonder if it would be possible to continue (and ignore the pubname) here as well, if the name was read first. Reading the name I assume would be necessary to keep iteration in sync? See diff below. This would allow some debugging even though some .debug_pubnames entries would not be found if offsets are broken. Perhaps this is a bad workaround for broken debug information? --- a/src/extensions/tcf-agent.mirror/tcf_agent/agent/tcf/services/dwarfcache.c +++ b/src/extensions/tcf-agent.mirror/tcf_agent/agent/tcf/services/dwarfcache.c @@ -1281,9 +1281,14 @@ static void load_pub_names(ELF_Section * debug_info, ELF_Section * pub_names) { ObjectInfo * info = NULL; U8_T obj_offs = dwarf64 ? dio_ReadU8() : (U8_T)dio_ReadU4(); if (obj_offs == 0) break; - if (obj_offs >= unit_size) str_fmt_exception(ERR_INV_DWARF, - "Invalid object offset in %s section", pub_names->name); name = dio_ReadString(); + if (obj_offs >= unit_size) { + trace(LOG_ALWAYS, "Invalid public name offset 0x%x for" + " '%s' in section '%s', CU 0x%x with size 0x%x", + obj_offs, name, pub_names->name, unit_addr, + unit_size); + continue; + } ---------------------------------------------------------------------- This e-mail and any attachments may contain confidential material for This email and any attachments are intended for the sole use of the named recipient(s) and contain(s) confidential information that may be proprietary, privileged or copyrighted under applicable law. If you are not the intended recipient, do not read, copy, or forward this email message or any attachments. Delete this email message and any attachments immediately. |