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8256594: Unexpected warning: SIGSEGV handler flags expected:SA_RESTART|SA_SIGINFO found:SA_RESTART|SA_SIGINFO

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Reviewed-by: stuefe, coleenp, dcubed
This commit is contained in:
David Holmes 2020-11-20 04:17:27 +00:00
parent 4c095252a5
commit fa240f2261
1 changed files with 33 additions and 4 deletions
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37
src/hotspot/os/posix/signals_posix.cpp
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@ -47,6 +47,14 @@
// signal handling (except suspend/resume)
// suspend/resume
// Glibc on Linux uses the SA_RESTORER flag to indicate
// the use of a "signal trampoline". We have no interest
// in this flag and need to ignore it when checking our
// own flag settings.
// Note: SA_RESTORER is not exposed through signal.h so we
// have to hardwire its 0x04000000 value in the mask.
LINUX_ONLY(const int SA_RESTORER_FLAG_MASK = ~0x04000000;)
// Todo: provide a os::get_max_process_id() or similar. Number of processes
// may have been configured, can be read more accurately from proc fs etc.
#ifndef MAX_PID
@ -657,9 +665,19 @@ static const char* describe_sa_flags(int flags, char* buffer, size_t size) {
strncpy(buffer, "none", size);
const unsigned int unknown_flag = ~(SA_NOCLDSTOP |
SA_ONSTACK |
SA_NOCLDSTOP |
SA_RESTART |
SA_SIGINFO |
SA_NOCLDWAIT |
SA_NODEFER
AIX_ONLY(| SA_OLDSTYLE)
);
const struct {
// NB: i is an unsigned int here because SA_RESETHAND is on some
// systems 0x80000000, which is implicitly unsigned. Assignining
// systems 0x80000000, which is implicitly unsigned. Assigning
// it to an int field would be an overflow in unsigned-to-signed
// conversion.
unsigned int i;
@ -675,10 +693,10 @@ static const char* describe_sa_flags(int flags, char* buffer, size_t size) {
#if defined(AIX)
{ SA_OLDSTYLE, "SA_OLDSTYLE" },
#endif
{ 0, NULL }
{ unknown_flag, "NOT USED" }
};
for (idx = 0; flaginfo[idx].s && remaining > 1; idx++) {
for (idx = 0; flaginfo[idx].i != unknown_flag && remaining > 1; idx++) {
if (flags & flaginfo[idx].i) {
if (first) {
jio_snprintf(p, remaining, "%s", flaginfo[idx].s);
@ -691,6 +709,10 @@ static const char* describe_sa_flags(int flags, char* buffer, size_t size) {
remaining -= len;
}
}
unsigned int unknowns = flags & unknown_flag;
if (unknowns != 0) {
jio_snprintf(p, remaining, "|Unknown_flags:%x", unknowns);
}
buffer[size - 1] = '\0';
@ -734,6 +756,9 @@ static void check_signal_handler(int sig) {
os_sigaction(sig, (struct sigaction*)NULL, &act);
// See comment for SA_RESTORER_FLAG_MASK
LINUX_ONLY(act.sa_flags &= SA_RESTORER_FLAG_MASK;)
address thisHandler = (act.sa_flags & SA_SIGINFO)
? CAST_FROM_FN_PTR(address, act.sa_sigaction)
: CAST_FROM_FN_PTR(address, act.sa_handler);
@ -1310,6 +1335,9 @@ void PosixSignals::print_signal_handler(outputStream* st, int sig,
struct sigaction sa;
sigaction(sig, NULL, &sa);
// See comment for SA_RESTORER_FLAG_MASK
LINUX_ONLY(sa.sa_flags &= SA_RESTORER_FLAG_MASK;)
st->print("%s: ", os::exception_name(sig, buf, buflen));
address handler = (sa.sa_flags & SA_SIGINFO)
@ -1331,7 +1359,8 @@ void PosixSignals::print_signal_handler(outputStream* st, int sig,
// May be, handler was resetted by VMError?
if (rh != NULL) {
handler = rh;
sa.sa_flags = VMError::get_resetted_sigflags(sig);
// See comment for SA_RESTORER_FLAG_MASK
sa.sa_flags = VMError::get_resetted_sigflags(sig) LINUX_ONLY(& SA_RESTORER_FLAG_MASK);
}
// Print textual representation of sa_flags.