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LibC: Use IP instead of si_addr for faulting instruction

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si_addr only means faulting instruction for SIGILL. For SIGSEGV it is
the faulting memory address.
This commit is contained in:
Bananymous
2026-04-08 12:38:42 +03:00
parent cd7d309fd1
commit 7333008f40
1 changed files with 19 additions and 18 deletions
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37
userspace/libraries/LibC/unistd.cpp
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@@ -193,7 +193,7 @@ static void __dump_symbol(int fd, const void* address)
#endif #endif
} }
static void __dump_backtrace(int sig, siginfo_t* info, void* context) static void __dump_backtrace(int sig, siginfo_t*, void* context)
{ {
constexpr auto signal_name = constexpr auto signal_name =
[](int signal) -> const char* [](int signal) -> const char*
@@ -208,6 +208,23 @@ static void __dump_backtrace(int sig, siginfo_t* info, void* context)
return "unknown signal"; return "unknown signal";
}; };
const auto* ucontext = static_cast<ucontext_t*>(context);
#if defined(__x86_64__)
const uintptr_t stack_base = ucontext->uc_mcontext.gregs[REG_RBP];
const uintptr_t instruction = ucontext->uc_mcontext.gregs[REG_RIP];
#elif defined(__i686__)
const uintptr_t stack_base = ucontext->uc_mcontext.gregs[REG_EBP];
const uintptr_t instruction = ucontext->uc_mcontext.gregs[REG_EIP];
#endif
struct stackframe
{
const stackframe* bp;
void* ip;
};
const auto* stackframe = reinterpret_cast<struct stackframe*>(stack_base);
// NOTE: we cannot use stddbf as that is not async-signal-safe. // NOTE: we cannot use stddbf as that is not async-signal-safe.
// POSIX says dprintf isn't either but our implementation is! // POSIX says dprintf isn't either but our implementation is!
@@ -220,23 +237,7 @@ static void __dump_backtrace(int sig, siginfo_t* info, void* context)
dprintf(fd, "received %s, backtrace:\n", signal_name(sig)); dprintf(fd, "received %s, backtrace:\n", signal_name(sig));
__dump_symbol(fd, info->si_addr); __dump_symbol(fd, reinterpret_cast<void*>(instruction));
struct stackframe
{
const stackframe* bp;
void* ip;
};
const auto* ucontext = static_cast<ucontext_t*>(context);
#if defined(__x86_64__)
const uintptr_t stack_base = ucontext->uc_mcontext.gregs[REG_RBP];
#elif defined(__i686__)
const uintptr_t stack_base = ucontext->uc_mcontext.gregs[REG_EBP];
#endif
const auto* stackframe = reinterpret_cast<struct stackframe*>(stack_base);
for (size_t i = 0; i < 128 && stackframe; i++) for (size_t i = 0; i < 128 && stackframe; i++)
{ {
__dump_symbol(fd, stackframe->ip); __dump_symbol(fd, stackframe->ip);