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Commit db018bf7 authored by Carl Shapiro's avatar Carl Shapiro
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runtime: restrict stack root scan to locals and arguments 

R=rsc
CC=golang-dev
https://golang.org/cl/7301062
parent 6a752520
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Inline Side-by-side
Showing with 77 additions and 57 deletions
src/pkg/runtime/mgc0.c
View file @ db018bf7
......@@ -1299,52 +1299,53 @@ addroot(Obj obj)
work.nroot++;
}
static void
addframeroots(Func *f, byte*, byte *sp, void*)
{
if (f->frame > sizeof(uintptr))
addroot((Obj){sp, f->frame - sizeof(uintptr), 0});
if (f->args > 0)
addroot((Obj){sp + f->frame, f->args, 0});
}
static void
addstackroots(G *gp)
{
M *mp;
int32 n;
Stktop *stk;
byte *sp, *guard;
stk = (Stktop*)gp->stackbase;
guard = (byte*)gp->stackguard;
Func *f;
byte *sp, *pc;
if(gp == g) {
// Scanning our own stack: start at &gp.
sp = (byte*)&gp;
pc = runtime·getcallerpc(&gp);
} else if((mp = gp->m) != nil && mp->helpgc) {
// gchelper's stack is in active use and has no interesting pointers.
return;
} else if(gp->gcstack != (uintptr)nil) {
// Scanning another goroutine that is about to enter or might
// have just exited a system call. It may be executing code such
// as schedlock and may have needed to start a new stack segment.
// Use the stack segment and stack pointer at the time of
// the system call instead, since that won't change underfoot.
sp = (byte*)gp->gcsp;
pc = gp->gcpc;
} else {
// Scanning another goroutine's stack.
// The goroutine is usually asleep (the world is stopped).
sp = (byte*)gp->sched.sp;
// The exception is that if the goroutine is about to enter or might
// have just exited a system call, it may be executing code such
// as schedlock and may have needed to start a new stack segment.
// Use the stack segment and stack pointer at the time of
// the system call instead, since that won't change underfoot.
if(gp->gcstack != (uintptr)nil) {
stk = (Stktop*)gp->gcstack;
sp = (byte*)gp->gcsp;
guard = (byte*)gp->gcguard;
}
}
n = 0;
while(stk) {
if(sp < guard-StackGuard || (byte*)stk < sp) {
runtime·printf("scanstack inconsistent: g%D#%d sp=%p not in [%p,%p]\n", gp->goid, n, sp, guard-StackGuard, stk);
runtime·throw("scanstack");
pc = gp->sched.pc;
if (pc == (byte*)runtime·goexit && gp->fnstart != nil) {
// The goroutine has not started. Its incoming
// arguments are at the top of the stack and must
// be scanned. No other data on the stack.
f = runtime·findfunc((uintptr)gp->fnstart->fn);
if (f->args > 0)
addroot((Obj){sp, f->args, 0});
return;
}
addroot((Obj){sp, (byte*)stk - sp, 0});
sp = (byte*)stk->gobuf.sp;
guard = stk->stackguard;
stk = (Stktop*)stk->stackbase;
n++;
}
runtime·gentraceback(pc, sp, nil, gp, 0, nil, 0x7fffffff, addframeroots, nil);
}
static void
......
src/pkg/runtime/mprof.goc
View file @ db018bf7
......@@ -511,7 +511,7 @@ saveg(byte *pc, byte *sp, G *gp, TRecord *r)
{
int32 n;
n = runtime·gentraceback(pc, sp, 0, gp, 0, r->stk, nelem(r->stk));
n = runtime·gentraceback(pc, sp, 0, gp, 0, r->stk, nelem(r->stk), nil, nil);
if(n < nelem(r->stk))
r->stk[n] = 0;
}
......
src/pkg/runtime/proc.c
View file @ db018bf7
......@@ -1710,7 +1710,7 @@ runtime·sigprof(uint8 *pc, uint8 *sp, uint8 *lr, G *gp)
runtime·unlock(&prof);
return;
}
n = runtime·gentraceback(pc, sp, lr, gp, 0, prof.pcbuf, nelem(prof.pcbuf));
n = runtime·gentraceback(pc, sp, lr, gp, 0, prof.pcbuf, nelem(prof.pcbuf), nil, nil);
if(n > 0)
prof.fn(prof.pcbuf, n);
runtime·unlock(&prof);
......
src/pkg/runtime/runtime.h
View file @ db018bf7
......@@ -748,7 +748,7 @@ void runtime·exitsyscall(void);
G* runtime·newproc1(FuncVal*, byte*, int32, int32, void*);
bool runtime·sigsend(int32 sig);
int32 runtime·callers(int32, uintptr*, int32);
int32 runtime·gentraceback(byte*, byte*, byte*, G*, int32, uintptr*, int32);
int32 runtime·gentraceback(byte*, byte*, byte*, G*, int32, uintptr*, int32, void (*fn)(Func*, byte*, byte*, void*), void *arg);
int64 runtime·nanotime(void);
void runtime·dopanic(int32);
void runtime·startpanic(void);
......
src/pkg/runtime/sigqueue.goc
View file @ db018bf7
......@@ -83,7 +83,8 @@ runtime·sigsend(int32 s)
func signal_recv() (m uint32) {
static uint32 recv[nelem(sig.mask)];
uint32 i, old, new;
g->issystem = true;
for(;;) {
// Serve from local copy if there are bits left.
for(i=0; i<NSIG; i++) {
......
src/pkg/runtime/traceback_arm.c
View file @ db018bf7
......@@ -17,9 +17,9 @@ void _divu(void);
void _modu(void);
int32
runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr *pcbuf, int32 max)
runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr *pcbuf, int32 max, void (*fn)(Func*, byte*, byte*, void*), void *arg)
{
int32 i, n, iter;
int32 i, n;
uintptr pc, lr, tracepc, x;
byte *fp;
bool waspanic;
......@@ -46,7 +46,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
n = 0;
stk = (Stktop*)gp->stackbase;
for(iter = 0; iter < 100 && n < max; iter++) { // iter avoids looping forever
while(n < max) {
// Typically:
// pc is the PC of the running function.
// sp is the stack pointer at that program counter.
......@@ -60,14 +60,17 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
sp = (byte*)stk->gobuf.sp;
lr = 0;
fp = nil;
if(pcbuf == nil && runtime·showframe(nil, gp == m->curg))
if(pcbuf == nil && fn == nil && runtime·showframe(nil, gp == m->curg))
runtime·printf("----- stack segment boundary -----\n");
stk = (Stktop*)stk->stackbase;
continue;
}
if(pc <= 0x1000 || (f = runtime·findfunc(pc)) == nil)
if(pc <= 0x1000 || (f = runtime·findfunc(pc)) == nil) {
if(fn != nil)
runtime·throw("unknown pc");
break;
}
// Found an actual function.
if(lr == 0)
......@@ -82,6 +85,8 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
skip--;
else if(pcbuf != nil)
pcbuf[n++] = pc;
else if(fn != nil)
(*fn)(f, (byte*)pc, sp, arg);
else {
if(runtime·showframe(f, gp == m->curg)) {
// Print during crash.
......@@ -113,7 +118,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
waspanic = f->entry == (uintptr)runtime·sigpanic;
if(pcbuf == nil && f->entry == (uintptr)runtime·newstack && gp == m->g0) {
if(pcbuf == nil && fn == nil && f->entry == (uintptr)runtime·newstack && gp == m->g0) {
runtime·printf("----- newstack called from goroutine %D -----\n", m->curg->goid);
pc = (uintptr)m->morepc;
sp = (byte*)m->moreargp - sizeof(void*);
......@@ -124,7 +129,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
continue;
}
if(pcbuf == nil && f->entry == (uintptr)runtime·lessstack && gp == m->g0) {
if(pcbuf == nil && fn == nil && f->entry == (uintptr)runtime·lessstack && gp == m->g0) {
runtime·printf("----- lessstack called from goroutine %D -----\n", m->curg->goid);
gp = m->curg;
stk = (Stktop*)gp->stackbase;
......@@ -135,6 +140,10 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
continue;
}
// Do not unwind past the bottom of the stack.
if(pc == (uintptr)runtime·goexit)
break;
// Unwind to next frame.
pc = lr;
lr = 0;
......@@ -162,7 +171,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
}
}
if(pcbuf == nil && (pc = gp->gopc) != 0 && (f = runtime·findfunc(pc)) != nil
if(pcbuf == nil && fn == nil && (pc = gp->gopc) != 0 && (f = runtime·findfunc(pc)) != nil
&& runtime·showframe(f, gp == m->curg) && gp->goid != 1) {
runtime·printf("created by %S\n", f->name);
tracepc = pc; // back up to CALL instruction for funcline.
......@@ -186,7 +195,7 @@ runtime·traceback(byte *pc0, byte *sp, byte *lr, G *gp)
sp = (byte*)gp->sched.sp;
lr = nil;
}
runtime·gentraceback(pc0, sp, lr, gp, 0, nil, 100);
runtime·gentraceback(pc0, sp, lr, gp, 0, nil, 100, nil, nil);
}
// func caller(n int) (pc uintptr, file string, line int, ok bool)
......@@ -198,5 +207,5 @@ runtime·callers(int32 skip, uintptr *pcbuf, int32 m)
sp = runtime·getcallersp(&skip);
pc = runtime·getcallerpc(&skip);
return runtime·gentraceback(pc, sp, 0, g, skip, pcbuf, m);
return runtime·gentraceback(pc, sp, 0, g, skip, pcbuf, m, nil, nil);
}
src/pkg/runtime/traceback_x86.c
View file @ db018bf7
......@@ -17,14 +17,14 @@ void runtime·sigpanic(void);
// This code is also used for the 386 tracebacks.
// Use uintptr for an appropriate word-sized integer.
// Generic traceback. Handles runtime stack prints (pcbuf == nil)
// as well as the runtime.Callers function (pcbuf != nil).
// A little clunky to merge the two but avoids duplicating
// the code and all its subtlety.
// Generic traceback. Handles runtime stack prints (pcbuf == nil),
// the runtime.Callers function (pcbuf != nil), as well as the garbage
// collector (fn != nil). A little clunky to merge the two but avoids
// duplicating the code and all its subtlety.
int32
runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr *pcbuf, int32 max)
runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr *pcbuf, int32 max, void (*fn)(Func*, byte*, byte*, void*), void *arg)
{
int32 i, n, iter, sawnewstack;
int32 i, n, sawnewstack;
uintptr pc, lr, tracepc;
byte *fp;
Stktop *stk;
......@@ -54,7 +54,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
n = 0;
sawnewstack = 0;
stk = (Stktop*)gp->stackbase;
for(iter = 0; iter < 100 && n < max; iter++) { // iter avoids looping forever
while(n < max) {
// Typically:
// pc is the PC of the running function.
// sp is the stack pointer at that program counter.
......@@ -68,13 +68,16 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
sp = (byte*)stk->gobuf.sp;
lr = 0;
fp = nil;
if(pcbuf == nil && runtime·showframe(nil, gp == m->curg))
if(pcbuf == nil && fn == nil && runtime·showframe(nil, gp == m->curg))
runtime·printf("----- stack segment boundary -----\n");
stk = (Stktop*)stk->stackbase;
continue;
}
if(pc <= 0x1000 || (f = runtime·findfunc(pc)) == nil)
if(pc <= 0x1000 || (f = runtime·findfunc(pc)) == nil) {
if(fn != nil)
runtime·throw("unknown pc");
break;
}
// Found an actual function.
if(fp == nil) {
......@@ -91,6 +94,8 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
skip--;
else if(pcbuf != nil)
pcbuf[n++] = pc;
else if(fn != nil)
(*fn)(f, (byte*)pc, sp, arg);
else {
if(runtime·showframe(f, gp == m->curg)) {
// Print during crash.
......@@ -129,7 +134,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
if(f->entry == (uintptr)runtime·newstack)
sawnewstack = 1;
if(pcbuf == nil && f->entry == (uintptr)runtime·morestack && gp == m->g0 && sawnewstack) {
if(pcbuf == nil && fn == nil && f->entry == (uintptr)runtime·morestack && gp == m->g0 && sawnewstack) {
// The fact that we saw newstack means that morestack
// has managed to record its information in m, so we can
// use it to keep unwinding the stack.
......@@ -144,7 +149,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
continue;
}
if(pcbuf == nil && f->entry == (uintptr)runtime·lessstack && gp == m->g0) {
if(pcbuf == nil && fn == nil && f->entry == (uintptr)runtime·lessstack && gp == m->g0) {
// Lessstack is running on scheduler stack. Switch to original goroutine.
runtime·printf("----- lessstack called from goroutine %D -----\n", m->curg->goid);
gp = m->curg;
......@@ -156,6 +161,10 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
continue;
}
// Do not unwind past the bottom of the stack.
if(pc == (uintptr)runtime·goexit)
break;
// Unwind to next frame.
pc = lr;
lr = 0;
......@@ -164,7 +173,7 @@ runtime·gentraceback(byte *pc0, byte *sp, byte *lr0, G *gp, int32 skip, uintptr
}
// Show what created goroutine, except main goroutine (goid 1).
if(pcbuf == nil && (pc = gp->gopc) != 0 && (f = runtime·findfunc(pc)) != nil
if(pcbuf == nil && fn == nil && (pc = gp->gopc) != 0 && (f = runtime·findfunc(pc)) != nil
&& runtime·showframe(f, gp == m->curg) && gp->goid != 1) {
runtime·printf("created by %S\n", f->name);
tracepc = pc; // back up to CALL instruction for funcline.
......@@ -187,7 +196,7 @@ runtime·traceback(byte *pc0, byte *sp, byte*, G *gp)
pc0 = gp->sched.pc;
sp = (byte*)gp->sched.sp;
}
runtime·gentraceback(pc0, sp, nil, gp, 0, nil, 100);
runtime·gentraceback(pc0, sp, nil, gp, 0, nil, 100, nil, nil);
}
int32
......@@ -199,5 +208,5 @@ runtime·callers(int32 skip, uintptr *pcbuf, int32 m)
sp = (byte*)&skip;
pc = runtime·getcallerpc(&skip);
return runtime·gentraceback(pc, sp, nil, g, skip, pcbuf, m);
return runtime·gentraceback(pc, sp, nil, g, skip, pcbuf, m, nil, nil);
}
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