* [dm-devel] [PATCH v2] multipathd: fix compilation issue with liburcu < 0.8
@ 2021-05-13 19:53 mwilck
2021-05-14 19:00 ` Benjamin Marzinski
0 siblings, 1 reply; 2+ messages in thread
From: mwilck @ 2021-05-13 19:53 UTC (permalink / raw)
To: Christophe Varoqui, Benjamin Marzinski; +Cc: dm-devel, Martin Wilck
From: Martin Wilck <mwilck@suse.com>
To avoid race conditions with pending RCU callbacks on exit, it's
necessary to call rcu_barrier() in cleanup_rcu() (see
https://lists.lttng.org/pipermail/lttng-dev/2021-May/029958.html and
follow-ups).
rcu_barrier() is only available in User-space RCU v0.8 and newer.
Fix it by reverting 5d0dae6 ("multipathd: Fix liburcu memory leak")
if an older version of liburcu is detected.
Fixes: 5d0dae6 ("multipathd: Fix liburcu memory leak")
Signed-off-by: Martin Wilck <mwilck@suse.com>
---
v2: Use $(PKGCONFIG) (Ben Marzinski); remove "\n" in awk.
---
multipathd/Makefile | 2 ++
multipathd/main.c | 17 +++++++++++++++--
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/multipathd/Makefile b/multipathd/Makefile
index d053c1e..393b6cb 100644
--- a/multipathd/Makefile
+++ b/multipathd/Makefile
@@ -16,6 +16,8 @@ LDFLAGS += $(BIN_LDFLAGS)
LIBDEPS += -L$(multipathdir) -lmultipath -L$(mpathpersistdir) -lmpathpersist \
-L$(mpathcmddir) -lmpathcmd -ludev -ldl -lurcu -lpthread \
-ldevmapper -lreadline
+CFLAGS += $(shell $(PKGCONFIG) --modversion liburcu 2>/dev/null | \
+ awk -F. '{ printf("-DURCU_VERSION=0x%06x", 256 * ( 256 * $$1 + $$2) + $$3); }')
ifdef SYSTEMD
CFLAGS += -DUSE_SYSTEMD=$(SYSTEMD)
diff --git a/multipathd/main.c b/multipathd/main.c
index 102946b..c34fd9c 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -3031,6 +3031,10 @@ static void cleanup_threads(void)
pthread_attr_destroy(&waiter_attr);
}
+#ifndef URCU_VERSION
+# define URCU_VERSION 0
+#endif
+#if (URCU_VERSION >= 0x000800)
/*
* Use a non-default call_rcu_data for child().
*
@@ -3040,6 +3044,9 @@ static void cleanup_threads(void)
* can't be joined with pthread_join(), leaving a memory leak.
*
* Therefore we create our own, which can be destroyed and joined.
+ * The cleanup handler needs to call rcu_barrier(), which is only
+ * available in user-space RCU v0.8 and newer. See
+ * https://lists.lttng.org/pipermail/lttng-dev/2021-May/029958.html
*/
static struct call_rcu_data *setup_rcu(void)
{
@@ -3072,6 +3079,7 @@ static void cleanup_rcu(void)
}
rcu_unregister_thread();
}
+#endif /* URCU_VERSION */
static void cleanup_child(void)
{
@@ -3116,9 +3124,14 @@ child (__attribute__((unused)) void *param)
init_unwinder();
mlockall(MCL_CURRENT | MCL_FUTURE);
signal_init();
+#if (URCU_VERSION >= 0x000800)
mp_rcu_data = setup_rcu();
-
- if (atexit(cleanup_rcu) || atexit(cleanup_child))
+ if (atexit(cleanup_rcu))
+ fprintf(stderr, "failed to register RCU cleanup handler\n");
+#else
+ rcu_init();
+#endif
+ if (atexit(cleanup_child))
fprintf(stderr, "failed to register cleanup handlers\n");
setup_thread_attr(&misc_attr, 64 * 1024, 0);
--
2.31.1
--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [dm-devel] [PATCH v2] multipathd: fix compilation issue with liburcu < 0.8
2021-05-13 19:53 [dm-devel] [PATCH v2] multipathd: fix compilation issue with liburcu < 0.8 mwilck
@ 2021-05-14 19:00 ` Benjamin Marzinski
0 siblings, 0 replies; 2+ messages in thread
From: Benjamin Marzinski @ 2021-05-14 19:00 UTC (permalink / raw)
To: mwilck; +Cc: dm-devel
On Thu, May 13, 2021 at 09:53:58PM +0200, mwilck@suse.com wrote:
> From: Martin Wilck <mwilck@suse.com>
>
> To avoid race conditions with pending RCU callbacks on exit, it's
> necessary to call rcu_barrier() in cleanup_rcu() (see
> https://lists.lttng.org/pipermail/lttng-dev/2021-May/029958.html and
> follow-ups).
>
> rcu_barrier() is only available in User-space RCU v0.8 and newer.
> Fix it by reverting 5d0dae6 ("multipathd: Fix liburcu memory leak")
> if an older version of liburcu is detected.
>
> Fixes: 5d0dae6 ("multipathd: Fix liburcu memory leak")
> Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
>
> ---
> v2: Use $(PKGCONFIG) (Ben Marzinski); remove "\n" in awk.
>
> ---
> multipathd/Makefile | 2 ++
> multipathd/main.c | 17 +++++++++++++++--
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/multipathd/Makefile b/multipathd/Makefile
> index d053c1e..393b6cb 100644
> --- a/multipathd/Makefile
> +++ b/multipathd/Makefile
> @@ -16,6 +16,8 @@ LDFLAGS += $(BIN_LDFLAGS)
> LIBDEPS += -L$(multipathdir) -lmultipath -L$(mpathpersistdir) -lmpathpersist \
> -L$(mpathcmddir) -lmpathcmd -ludev -ldl -lurcu -lpthread \
> -ldevmapper -lreadline
> +CFLAGS += $(shell $(PKGCONFIG) --modversion liburcu 2>/dev/null | \
> + awk -F. '{ printf("-DURCU_VERSION=0x%06x", 256 * ( 256 * $$1 + $$2) + $$3); }')
>
> ifdef SYSTEMD
> CFLAGS += -DUSE_SYSTEMD=$(SYSTEMD)
> diff --git a/multipathd/main.c b/multipathd/main.c
> index 102946b..c34fd9c 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -3031,6 +3031,10 @@ static void cleanup_threads(void)
> pthread_attr_destroy(&waiter_attr);
> }
>
> +#ifndef URCU_VERSION
> +# define URCU_VERSION 0
> +#endif
> +#if (URCU_VERSION >= 0x000800)
> /*
> * Use a non-default call_rcu_data for child().
> *
> @@ -3040,6 +3044,9 @@ static void cleanup_threads(void)
> * can't be joined with pthread_join(), leaving a memory leak.
> *
> * Therefore we create our own, which can be destroyed and joined.
> + * The cleanup handler needs to call rcu_barrier(), which is only
> + * available in user-space RCU v0.8 and newer. See
> + * https://lists.lttng.org/pipermail/lttng-dev/2021-May/029958.html
> */
> static struct call_rcu_data *setup_rcu(void)
> {
> @@ -3072,6 +3079,7 @@ static void cleanup_rcu(void)
> }
> rcu_unregister_thread();
> }
> +#endif /* URCU_VERSION */
>
> static void cleanup_child(void)
> {
> @@ -3116,9 +3124,14 @@ child (__attribute__((unused)) void *param)
> init_unwinder();
> mlockall(MCL_CURRENT | MCL_FUTURE);
> signal_init();
> +#if (URCU_VERSION >= 0x000800)
> mp_rcu_data = setup_rcu();
> -
> - if (atexit(cleanup_rcu) || atexit(cleanup_child))
> + if (atexit(cleanup_rcu))
> + fprintf(stderr, "failed to register RCU cleanup handler\n");
> +#else
> + rcu_init();
> +#endif
> + if (atexit(cleanup_child))
> fprintf(stderr, "failed to register cleanup handlers\n");
>
> setup_thread_attr(&misc_attr, 64 * 1024, 0);
> --
> 2.31.1
--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel
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2021-05-14 19:00 ` Benjamin Marzinski
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