Hi Marc-André, On 01/04/2018 01:05 PM, Marc-André Lureau wrote: > It helps ASAN to detect more leaks on coroutine stacks, as found in > the following patch. > > A similar work would need to be done for sigaltstack & windows fibers > to have similar coverage. Since ucontext is preferred, I didn't bother > checking the other coroutine implementations for now. > > Signed-off-by: Marc-André Lureau <[email protected]> > Reviewed-by: Philippe Mathieu-Daudé <[email protected]> > Reviewed-by: Stefan Hajnoczi <[email protected]> > --- > include/qemu/compiler.h | 4 ++++ > util/coroutine-ucontext.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 50 insertions(+) > > diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h > index 340e5fdc09..5fcc4f7ec7 100644 > --- a/include/qemu/compiler.h > +++ b/include/qemu/compiler.h > @@ -111,4 +111,8 @@ > #define GCC_FMT_ATTR(n, m) > #endif > > +#ifndef __has_feature > +#define __has_feature(x) 0 /* compatibility with non-clang compilers */ > +#endif > + > #endif /* COMPILER_H */ > diff --git a/util/coroutine-ucontext.c b/util/coroutine-ucontext.c > index 6621f3f692..e78eae8766 100644 > --- a/util/coroutine-ucontext.c > +++ b/util/coroutine-ucontext.c > @@ -31,6 +31,11 @@ > #include <valgrind/valgrind.h> > #endif > > +#if defined(__SANITIZE_ADDRESS__) || __has_feature(address_sanitizer) > +#define CONFIG_ASAN 1 > +#include <sanitizer/asan_interface.h> > +#endif
Sadly this fails on Travis:
$ export CONFIG="--enable-debug --enable-debug-tcg
--enable-trace-backends=log"
$ export CC=gcc
$ ./configure ${CONFIG}
C compiler gcc
Host C compiler cc
C++ compiler c++
Objective-C compiler clang
CFLAGS -Wno-maybe-uninitialized -Og -fsanitize=address -g
[...]
CC util/qemu-coroutine.o
CC util/qemu-coroutine-lock.o
CC util/qemu-coroutine-io.o
CC util/qemu-coroutine-sleep.o
CC util/coroutine-ucontext.o
util/coroutine-ucontext.c:36:38: fatal error:
sanitizer/asan_interface.h: No such file or directory
#include <sanitizer/asan_interface.h>
^
compilation terminated.
make: *** [util/coroutine-ucontext.o] Error 1
You simply need to update the .travis.yml, but does that mean your
previous patch "Enable ASAN/UBSan by default if the compiler supports
it." isn't correct?
> +
> typedef struct {
> Coroutine base;
> void *stack;
> @@ -59,11 +64,37 @@ union cc_arg {
> int i[2];
> };
>
> +static void finish_switch_fiber(void *fake_stack_save)
> +{
> +#ifdef CONFIG_ASAN
> + const void *bottom_old;
> + size_t size_old;
> +
> + __sanitizer_finish_switch_fiber(fake_stack_save, &bottom_old, &size_old);
> +
> + if (!leader.stack) {
> + leader.stack = (void *)bottom_old;
> + leader.stack_size = size_old;
> + }
> +#endif
> +}
> +
> +static void start_switch_fiber(void **fake_stack_save,
> + const void *bottom, size_t size)
> +{
> +#ifdef CONFIG_ASAN
> + __sanitizer_start_switch_fiber(fake_stack_save, bottom, size);
> +#endif
> +}
> +
> static void coroutine_trampoline(int i0, int i1)
> {
> union cc_arg arg;
> CoroutineUContext *self;
> Coroutine *co;
> + void *fake_stack_save = NULL;
> +
> + finish_switch_fiber(NULL);
>
> arg.i[0] = i0;
> arg.i[1] = i1;
> @@ -72,9 +103,13 @@ static void coroutine_trampoline(int i0, int i1)
>
> /* Initialize longjmp environment and switch back the caller */
> if (!sigsetjmp(self->env, 0)) {
> + start_switch_fiber(&fake_stack_save,
> + leader.stack, leader.stack_size);
> siglongjmp(*(sigjmp_buf *)co->entry_arg, 1);
> }
>
> + finish_switch_fiber(fake_stack_save);
> +
> while (true) {
> co->entry(co->entry_arg);
> qemu_coroutine_switch(co, co->caller, COROUTINE_TERMINATE);
> @@ -87,6 +122,7 @@ Coroutine *qemu_coroutine_new(void)
> ucontext_t old_uc, uc;
> sigjmp_buf old_env;
> union cc_arg arg = {0};
> + void *fake_stack_save = NULL;
>
> /* The ucontext functions preserve signal masks which incurs a
> * system call overhead. sigsetjmp(buf, 0)/siglongjmp() does not
> @@ -122,8 +158,12 @@ Coroutine *qemu_coroutine_new(void)
>
> /* swapcontext() in, siglongjmp() back out */
> if (!sigsetjmp(old_env, 0)) {
> + start_switch_fiber(&fake_stack_save, co->stack, co->stack_size);
> swapcontext(&old_uc, &uc);
> }
> +
> + finish_switch_fiber(fake_stack_save);
> +
> return &co->base;
> }
>
> @@ -169,13 +209,19 @@ qemu_coroutine_switch(Coroutine *from_, Coroutine *to_,
> CoroutineUContext *from = DO_UPCAST(CoroutineUContext, base, from_);
> CoroutineUContext *to = DO_UPCAST(CoroutineUContext, base, to_);
> int ret;
> + void *fake_stack_save = NULL;
>
> current = to_;
>
> ret = sigsetjmp(from->env, 0);
> if (ret == 0) {
> + start_switch_fiber(action == COROUTINE_TERMINATE ?
> + NULL : &fake_stack_save, to->stack,
> to->stack_size);
> siglongjmp(to->env, action);
> }
> +
> + finish_switch_fiber(fake_stack_save);
> +
> return ret;
> }
>
>
signature.asc
Description: OpenPGP digital signature
