On Tue, 17 Aug 2021 08:57:19 +0530
<jer...@marvell.com> wrote:
> +#define oops_print(...) rte_log(RTE_LOG_ERR, RTE_LOGTYPE_EAL, __VA_ARGS__)
It is problematic to call rte_log from a signal handler.
The malloc pool maybe corrupted and rte_log can call functions that
use malloc.
Even rte_dump_stack() is unsafe from these signals.
> +
> +static int oops_signals[] = {SIGSEGV, SIGBUS, SIGILL, SIGABRT, SIGFPE,
> SIGSYS};
Should be constant.
> +
> +struct oops_signal {
> + int sig;
Redundant, you defined the oops_signals above.
> + bool enabled;
Redundant, you can just compare with action.
> + struct sigaction sa;
> +};
> +
> +static struct oops_signal signals_db[RTE_DIM(oops_signals)];
> +
> +static void
> +back_trace_dump(ucontext_t *context)
> +{
> + RTE_SET_USED(context);
> +
> + rte_dump_stack();
> +}
rte_dump_stack() is not safe in signal handler:
Recommend backtrace_symbols_fd ??
Better yet use libunwind
> +static void
> +siginfo_dump(int sig, siginfo_t *info)
> +{
> + oops_print("PID: %" PRIdMAX "\n", (intmax_t)getpid());
> +
> + if (info == NULL)
> + return;
> + if (sig != info->si_signo)
> + oops_print("Invalid signal info\n");
> +
> + oops_print("Signal number: %d\n", info->si_signo);
> + oops_print("Fault address: %p\n", info->si_addr);
> +}
> +
> +static void
> +mem32_dump(void *ptr)
Should be const
> +{
> + uint32_t *p = ptr;
> + int i;
> +
> + for (i = 0; i < 16; i++)
> + oops_print("%p: 0x%x\n", p + i, rte_be_to_cpu_32(p[i]));
> +}
Why reinvent hexdump?
> +
> +static void
> +stack_dump_header(void)
> +{
> + oops_print("Stack dump:\n");
> + oops_print("----------\n");
> +}
> +
> +static void
> +code_dump_header(void)
> +{
> + oops_print("Code dump:\n");
> + oops_print("----------\n");
> +}
> +
> +static void
> +stack_code_dump(void *stack, void *code)
> +{
> + if (stack == NULL || code == NULL)
> + return;
> +
> + oops_print("\n");
> + stack_dump_header();
> + mem32_dump(stack);
> + oops_print("\n");
> +
> + code_dump_header();
> + mem32_dump(code);
> + oops_print("\n");
> +}
> +static void
> +archinfo_dump(ucontext_t *uc)
> {
> - RTE_SET_USED(sig);
> - RTE_SET_USED(info);
> RTE_SET_USED(uc);
>
> + stack_code_dump(NULL, NULL);
> +}
> +
> +static void
> +default_signal_handler_invoke(int sig)
> +{
> + unsigned int idx;
> +
> + for (idx = 0; idx < RTE_DIM(oops_signals); idx++) {
> + /* Skip disabled signals */
> + if (signals_db[idx].sig != sig)
> + continue;
> + if (!signals_db[idx].enabled)
> + continue;
> + /* Replace with stored handler */
> + sigaction(sig, &signals_db[idx].sa, NULL);
> + kill(getpid(), sig);
If you use SA_RESETHAND, you don't need this stuff.
> + }
> +}
> +
> +void
> +rte_oops_decode(int sig, siginfo_t *info, ucontext_t *uc)
> +{
> + oops_print("Signal info:\n");
> + oops_print("------------\n");
> + siginfo_dump(sig, info);
> + oops_print("\n");
> +
> + oops_print("Backtrace:\n");
> + oops_print("----------\n");
> + back_trace_dump(uc);
> + oops_print("\n");
> +
> + oops_print("Arch info:\n");
> + oops_print("----------\n");
> + if (uc)
> + archinfo_dump(uc);
> +}
> +
> +static void
> +eal_oops_handler(int sig, siginfo_t *info, void *ctx)
> +{
> + ucontext_t *uc = ctx;
> +
> + rte_oops_decode(sig, info, uc);
> + default_signal_handler_invoke(sig);
If you use SA_RESETHAND, then just doing raise(sig) here.
> }
>
> int
> rte_oops_signals_enabled(int *signals)
Why is this necessary and exported?
> {
> - RTE_SET_USED(signals);
> + int count = 0, sig[RTE_OOPS_SIGNALS_MAX];
> + unsigned int idx = 0;
>
> - return 0;
> + for (idx = 0; idx < RTE_DIM(oops_signals); idx++) {
> + if (signals_db[idx].enabled) {
> + sig[count] = signals_db[idx].sig;
> + count++;
> + }
> + }
> + if (signals)
> + memcpy(signals, sig, sizeof(*signals) * count);
> +
> + return count;
> }
>
> int
> eal_oops_init(void)
> {
> - return 0;
> + unsigned int idx, rc = 0;
> + struct sigaction sa;
> +
> + RTE_BUILD_BUG_ON(RTE_DIM(oops_signals) > RTE_OOPS_SIGNALS_MAX);
> +
> + sigemptyset(&sa.sa_mask);
> + sa.sa_sigaction = &eal_oops_handler;
> + sa.sa_flags = SA_RESTART | SA_SIGINFO | SA_ONSTACK;
> +
> + for (idx = 0; idx < RTE_DIM(oops_signals); idx++) {
> + signals_db[idx].sig = oops_signals[idx];
> + /* Get exiting sigaction */
> + rc = sigaction(signals_db[idx].sig, NULL, &signals_db[idx].sa);
> + if (rc)
> + continue;
> + /* Replace with oops handler */
> + rc = sigaction(signals_db[idx].sig, &sa, NULL);
> + if (rc)
> + continue;
> + signals_db[idx].enabled = true;
> + }
> + return rc;
> }
>
> void
> eal_oops_fini(void)
> {
> + unsigned int idx;
> +
> + for (idx = 0; idx < RTE_DIM(oops_signals); idx++) {
> + if (!signals_db[idx].enabled)
> + continue;
> + /* Replace with stored handler */
> + sigaction(signals_db[idx].sig, &signals_db[idx].sa, NULL);
> + }
> }
