diff options
| author | Peter Collingbourne <pcc@google.com> | 2020-03-20 18:09:00 -0700 |
|---|---|---|
| committer | Peter Collingbourne <pcc@google.com> | 2020-03-27 20:00:06 -0700 |
| commit | f03af8844acbd63f257c51577834d2c126a41f47 (patch) | |
| tree | 8cde302d29f6c19ad6da6ed35becb8462dafced3 /debuggerd/handler/debuggerd_handler.cpp | |
| parent | f3d542fe9fe4b82affada29928921314375d42f8 (diff) | |
Read fault address on arm64 using proposed kernel API.
On aarch64, the top 8 bits of the address (i.e. the tag bits) of
the fault address in si_addr are always clear. This isn't ideal for
MTE which will require these bits in order to correctly diagnose
tag mismatches.
A proposed kernel patch [1] exposes the full fault address including
the tag bits as part of the ucontext. Change debuggerd to read this
fault address if available.
[1] https://patchwork.kernel.org/patch/11435077/
Bug: 135772972
Change-Id: Ia05be574113860f4e9ecc36a310c4b740e0c4afb
Diffstat (limited to 'debuggerd/handler/debuggerd_handler.cpp')
| -rw-r--r-- | debuggerd/handler/debuggerd_handler.cpp | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/debuggerd/handler/debuggerd_handler.cpp b/debuggerd/handler/debuggerd_handler.cpp index 84d2bd09a..003c3d9a6 100644 --- a/debuggerd/handler/debuggerd_handler.cpp +++ b/debuggerd/handler/debuggerd_handler.cpp @@ -167,7 +167,7 @@ static bool get_main_thread_name(char* buf, size_t len) { * mutex is being held, so we don't want to use any libc functions that * could allocate memory or hold a lock. */ -static void log_signal_summary(const siginfo_t* info) { +static void log_signal_summary(const siginfo_t* info, const ucontext_t* ucontext) { char thread_name[MAX_TASK_NAME_LEN + 1]; // one more for termination if (prctl(PR_GET_NAME, reinterpret_cast<unsigned long>(thread_name), 0, 0, 0) != 0) { strcpy(thread_name, "<name unknown>"); @@ -186,7 +186,8 @@ static void log_signal_summary(const siginfo_t* info) { // Many signals don't have an address or sender. char addr_desc[32] = ""; // ", fault addr 0x1234" if (signal_has_si_addr(info)) { - async_safe_format_buffer(addr_desc, sizeof(addr_desc), ", fault addr %p", info->si_addr); + async_safe_format_buffer(addr_desc, sizeof(addr_desc), ", fault addr %p", + reinterpret_cast<void*>(get_fault_address(info, ucontext))); } pid_t self_pid = __getpid(); char sender_desc[32] = {}; // " from pid 1234, uid 666" @@ -476,6 +477,8 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c // making a syscall and checking errno. ErrnoRestorer restorer; + auto *ucontext = static_cast<ucontext_t*>(context); + // It's possible somebody cleared the SA_SIGINFO flag, which would mean // our "info" arg holds an undefined value. if (!have_siginfo(signal_number)) { @@ -522,7 +525,7 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c // This check might be racy if another thread sets NO_NEW_PRIVS, but this should be unlikely, // you can only set NO_NEW_PRIVS to 1, and the effect should be at worst a single missing // ANR trace. - debuggerd_fallback_handler(info, static_cast<ucontext_t*>(context), process_info.abort_msg); + debuggerd_fallback_handler(info, ucontext, process_info.abort_msg); resend_signal(info); return; } @@ -534,7 +537,7 @@ static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* c return; } - log_signal_summary(info); + log_signal_summary(info, ucontext); debugger_thread_info thread_info = { .crashing_tid = __gettid(), |