linux_core_dumper: support NT_SIGINFO for reading crashing address

The current core dumper only parses NT_PRSTATUS notes.  With signal
details, this note only includes three fields: signo, code, and errno.
We set exception_code to signo and exception_flag to code.  The errno
value isn't set by the kernel, so there's no need to save it.

However, we never fill in exception_address which means all converted
crashes look like they happen at address 0.  This implies a NULL jump
which is usually not the case, so it's just confusing.  The prstatus
structure doesn't offer anything directly that tracks this.

Starting with linux-3.7, the kernel writes out the full siginfo
structure in the NT_SIGINFO note.  So lets support that to pull out
si_addr which, for a bunch of common signals, is the value we want in
exception_address.

The size of the siginfo_t structure should be locked to 128 bytes at
build time for all architectures, so this should hopefully be stable.

Bug: google-breakpad:790
Change-Id: I458bad4787b1a8b73fad8fe068e9f23bec957599
Reviewed-on: https://chromium-review.googlesource.com/c/1497661
Reviewed-by: Mark Mentovai <mark@chromium.org>
This commit is contained in:
Mike Frysinger 2019-03-02 02:02:12 -05:00
parent 19a8433a60
commit 59d89be2d6

View File

@ -165,6 +165,7 @@ bool LinuxCoreDumper::EnumerateThreads() {
// -------------------------------------------------------------------
// 1st thread CORE NT_PRSTATUS
// process-wide CORE NT_PRPSINFO
// process-wide CORE NT_SIGINFO
// process-wide CORE NT_AUXV
// 1st thread CORE NT_FPREGSET
// 1st thread LINUX NT_PRXFPREG
@ -219,6 +220,28 @@ bool LinuxCoreDumper::EnumerateThreads() {
thread_infos_.push_back(info);
break;
}
case NT_SIGINFO: {
if (description.length() != sizeof(siginfo_t)) {
fprintf(stderr, "Found NT_SIGINFO descriptor of unexpected size\n");
return false;
}
const siginfo_t* info =
reinterpret_cast<const siginfo_t*>(description.data());
// Set crash_address when si_addr is valid for the signal.
switch (info->si_signo) {
case MD_EXCEPTION_CODE_LIN_SIGBUS:
case MD_EXCEPTION_CODE_LIN_SIGFPE:
case MD_EXCEPTION_CODE_LIN_SIGILL:
case MD_EXCEPTION_CODE_LIN_SIGSEGV:
case MD_EXCEPTION_CODE_LIN_SIGSYS:
case MD_EXCEPTION_CODE_LIN_SIGTRAP:
crash_address_ = reinterpret_cast<uintptr_t>(info->si_addr);
break;
}
break;
}
#if defined(__i386) || defined(__x86_64)
case NT_FPREGSET: {
if (thread_infos_.empty())