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>
diff --git a/src/client/linux/minidump_writer/linux_core_dumper.cc b/src/client/linux/minidump_writer/linux_core_dumper.cc
index 9bf2d2e..9a2f4d6 100644
--- a/src/client/linux/minidump_writer/linux_core_dumper.cc
+++ b/src/client/linux/minidump_writer/linux_core_dumper.cc
@@ -165,6 +165,7 @@
// -------------------------------------------------------------------
// 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 @@
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())
