From: Stefan Hajnoczi <stefanha@gmail.com>
To: Robert Foley <robert.foley@linaro.org>
Cc: peter.puhov@linaro.org, cota@braap.org, alex.bennee@linaro.org,
qemu-devel@nongnu.org, Lingfeng Yang <lfy@google.com>
Subject: Re: [PATCH 01/19] configure: add --enable-tsan flag + fiber annotations for coroutine-ucontext
Date: Wed, 17 Jun 2020 15:24:07 +0100 [thread overview]
Message-ID: <20200617142407.GH1728005@stefanha-x1.localdomain> (raw)
In-Reply-To: <20200522160755.886-2-robert.foley@linaro.org>
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On Fri, May 22, 2020 at 12:07:37PM -0400, Robert Foley wrote:
> +#define UC_DEBUG 0
> +#if UC_DEBUG && defined(CONFIG_TSAN)
> +#define UC_TRACE(fmt, ...) fprintf(stderr, "%s:%d:%p " fmt "\n", \
> + __func__, __LINE__, __tsan_get_current_fiber(), ##__VA_ARGS__);
> +#else
> +#define UC_TRACE(fmt, ...)
> +#endif
QEMU has tracing support, see docs/devel/tracing.txt. These fprintfs
should be trace events defined in the util/trace-events file.
> +
> /**
> * Per-thread coroutine bookkeeping
> */
> @@ -65,7 +80,20 @@ union cc_arg {
> int i[2];
> };
>
> -static void finish_switch_fiber(void *fake_stack_save)
> +/* QEMU_ALWAYS_INLINE only does so if __OPTIMIZE__, so we cannot use it. */
> +static inline __attribute__((always_inline))
Please document why always_inline is necessary here and in other
functions. Is it for performance or because the __tsan_*() functions
need to be called from a the parent function?
> +void on_new_fiber(CoroutineUContext *co)
> +{
> +#ifdef CONFIG_TSAN
> + co->tsan_co_fiber = __tsan_create_fiber(0); /* flags: sync on switch */
> + co->tsan_caller_fiber = __tsan_get_current_fiber();
> + UC_TRACE("Create new TSAN co fiber. co: %p co fiber: %p caller fiber: %p ",
> + co, co->tsan_co_fiber, co->tsan_caller_fiber);
> +#endif
> +}
> +
> +static inline __attribute__((always_inline))
> +void finish_switch_fiber(void *fake_stack_save)
> {
> #ifdef CONFIG_ASAN
> const void *bottom_old;
> @@ -78,18 +106,40 @@ static void finish_switch_fiber(void *fake_stack_save)
> leader.stack_size = size_old;
> }
> #endif
> +#ifdef CONFIG_TSAN
> + if (fake_stack_save) {
> + __tsan_release(fake_stack_save);
> + __tsan_switch_to_fiber(fake_stack_save, 0); /* 0=synchronize */
> + }
> +#endif
> }
>
> -static void start_switch_fiber(void **fake_stack_save,
> - const void *bottom, size_t size)
> +static inline __attribute__((always_inline)) void start_switch_fiber(
> + CoroutineAction action, void **fake_stack_save,
> + const void *bottom, size_t size, void *new_fiber)
> {
> #ifdef CONFIG_ASAN
> - __sanitizer_start_switch_fiber(fake_stack_save, bottom, size);
> + if (action == COROUTINE_TERMINATE) {
> + __sanitizer_start_switch_fiber(
> + action == COROUTINE_TERMINATE ? NULL : fake_stack_save,
The if statement already checks action == COROUTINE_TERMINATE, why is it
being checked again?
I think the old behavior can be retained by dropping the if statement
like this:
__sanitizer_start_switch_fiber(action == COROUTINE_TERMINATE ?
NULL : fake_stack_save,
bottom, size);
> + bottom, size);
> + }
> +#endif
> +#ifdef CONFIG_TSAN
> + void *curr_fiber =
> + __tsan_get_current_fiber();
> + __tsan_acquire(curr_fiber);
> +
> + UC_TRACE("Current fiber: %p.", curr_fiber);
> + *fake_stack_save = curr_fiber;
> + UC_TRACE("Switch to fiber %p", new_fiber);
> + __tsan_switch_to_fiber(new_fiber, 0); /* 0=synchronize */
> #endif
> }
Please split start_switch_fiber() into two functions:
start_switch_fiber_asan() and start_switch_fiber_tsan(). That way the
asan- and tsan-specific arguments can be kept separate and the
co->tsan_* fields only need to be compiled in when CONFIG_TSAN is
defined.
For example:
static inline __attribute__((always_inline))
void start_switch_fiber_tsan(void **fake_stack_save,
CoroutineUContext *co,
bool caller)
{
#ifdef CONFIG_TSAN
void *new_fiber = caller ?
co->tsan_caller_fiber :
co->tsan_co_fiber;
void *curr_fiber = __tsan_get_current_fiber();
__tsan_acquire(curr_fiber);
UC_TRACE("Current fiber: %p.", curr_fiber);
*fake_stack_save = curr_fiber;
UC_TRACE("Switch to fiber %p", new_fiber);
__tsan_switch_to_fiber(new_fiber, 0); /* 0=synchronize */
#endif
}
This does two things:
1. Unrelated ASAN and TSAN code is separate and each function only
has arguments that are actually needed.
2. The co->tsan_caller_fiber and co->tsan_co_fiber fields are only
access from within #ifdef CONFIG_TSAN.
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next prev parent reply other threads:[~2020-06-17 14:26 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 16:07 [PATCH 00/19] Add Thread Sanitizer support to QEMU Robert Foley
2020-05-22 16:07 ` [PATCH 01/19] configure: add --enable-tsan flag + fiber annotations for coroutine-ucontext Robert Foley
2020-05-23 16:55 ` Philippe Mathieu-Daudé
2020-05-26 12:38 ` Robert Foley
2020-06-17 14:24 ` Stefan Hajnoczi [this message]
2020-06-17 15:56 ` Alex Bennée
2020-06-17 21:27 ` Robert Foley
2020-05-22 16:07 ` [PATCH 02/19] cpu: convert queued work to a QSIMPLEQ Robert Foley
2020-05-24 10:20 ` Philippe Mathieu-Daudé
2020-05-26 15:01 ` Robert Foley
2020-05-22 16:07 ` [PATCH 03/19] thread: add qemu_spin_destroy Robert Foley
2020-05-22 16:07 ` [PATCH 04/19] cputlb: destroy CPUTLB with tlb_destroy Robert Foley
2020-05-22 16:07 ` [PATCH 05/19] qht: call qemu_spin_destroy for head buckets Robert Foley
2020-05-22 16:07 ` [PATCH 06/19] tcg: call qemu_spin_destroy for tb->jmp_lock Robert Foley
2020-05-22 16:07 ` [PATCH 07/19] translate-all: call qemu_spin_destroy for PageDesc Robert Foley
2020-05-22 16:07 ` [PATCH 08/19] thread: add tsan annotations to QemuSpin Robert Foley
2020-05-22 16:07 ` [PATCH 09/19] tests/docker: Added docker build support for TSan Robert Foley
2020-05-22 16:07 ` [PATCH 10/19] include/qemu: Added tsan.h for annotations Robert Foley
2020-05-23 17:20 ` Emilio G. Cota
2020-05-23 21:37 ` Emilio G. Cota
2020-05-22 16:07 ` [PATCH 11/19] accel/tcg: Fixed tsan warnings related to parallel_cpus Robert Foley
2020-05-23 17:21 ` Emilio G. Cota
2020-05-22 16:07 ` [PATCH 12/19] configure: added tsan support for blacklist Robert Foley
2020-05-23 17:27 ` Emilio G. Cota
2020-05-26 14:07 ` Robert Foley
2020-05-22 16:07 ` [PATCH 13/19] accel/tcg: Fixed tsan warnings Robert Foley
2020-05-23 20:06 ` Emilio G. Cota
2020-05-26 15:14 ` Robert Foley
2020-05-26 18:47 ` Paolo Bonzini
2020-05-22 16:07 ` [PATCH 14/19] util/async: " Robert Foley
2020-05-23 20:12 ` Emilio G. Cota
2020-05-26 15:19 ` Robert Foley
2020-05-26 10:32 ` Stefan Hajnoczi
2020-05-26 15:21 ` Robert Foley
2020-05-22 16:07 ` [PATCH 15/19] qht: Fix " Robert Foley
2020-05-23 20:44 ` Emilio G. Cota
2020-05-22 16:07 ` [PATCH 16/19] util: fixed tsan warnings in thread_pool.c Robert Foley
2020-05-26 20:18 ` Paolo Bonzini
2020-05-22 16:07 ` [PATCH 17/19] util: Added tsan annotate for thread name Robert Foley
2020-05-23 20:29 ` Emilio G. Cota
2020-05-22 16:07 ` [PATCH 18/19] target/arm: Fix tsan warning in cpu.c Robert Foley
2020-05-22 17:44 ` Peter Maydell
2020-05-22 21:33 ` Robert Foley
2020-05-22 22:36 ` Peter Maydell
2020-05-23 17:18 ` Emilio G. Cota
2020-05-26 14:01 ` Robert Foley
2020-05-22 16:07 ` [PATCH 19/19] docs: Added details on TSan to testing.rst Robert Foley
2020-05-23 20:29 ` Emilio G. Cota
2020-05-22 21:07 ` [PATCH 00/19] Add Thread Sanitizer support to QEMU no-reply
2020-05-23 21:36 ` Emilio G. Cota
2020-05-26 15:18 ` Robert Foley
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