b05147c356
Change patch format to remove Git version
* Patches 0001-0122 only have the patch format modified
Update to the head of the upstream staging branch plus redhat patches
* Patches 0123-0134 & 1036-0142 are from the upstream staging branch
* Patches 0143-1046 have been submitted upstream
* Patch 0156 is a Red Hat only patch. Red Hat udev rules set ID_SERIAL
from 60-persistent-storage.rules instead of 55-scsi-sg3_id.rules.
Multipath's parse_vpd_pg83() function needs to match the ID_SERIAL
value from udev.
Rename files
* Previous patches 0123-0132 are now patches 1035 & 0147-0155
132 lines
4.0 KiB
Diff
132 lines
4.0 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
|
|
From: Martin Wilck <mwilck@suse.com>
|
|
Date: Thu, 17 Dec 2020 16:50:06 +0100
|
|
Subject: [PATCH] multipathd: add code to initalize unwinder
|
|
|
|
glibc's implementation of pthread_cancel() loads symbols from
|
|
libgcc_s.so using dlopen() when pthread_cancel() is called
|
|
for the first time. This happens even with LD_BIND_NOW=1.
|
|
This may imply the need for file system access when a thread is
|
|
cancelled, which in the case of multipath-tools might be in a
|
|
dangerous situation where multipathd must avoid blocking.
|
|
|
|
Call load_unwinder() during startup to make sure the dynamic
|
|
linker has all necessary symbols resolved early on.
|
|
|
|
This implementation simply creates a dummy thread and cancels
|
|
it. This way all necessary symbols for thread cancellation
|
|
will be loaded, no matter what the C library needs to implement
|
|
cancellation.
|
|
|
|
Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
|
|
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
|
|
---
|
|
multipathd/Makefile | 2 +-
|
|
multipathd/init_unwinder.c | 34 ++++++++++++++++++++++++++++++++++
|
|
multipathd/init_unwinder.h | 21 +++++++++++++++++++++
|
|
multipathd/main.c | 2 ++
|
|
4 files changed, 58 insertions(+), 1 deletion(-)
|
|
create mode 100644 multipathd/init_unwinder.c
|
|
create mode 100644 multipathd/init_unwinder.h
|
|
|
|
diff --git a/multipathd/Makefile b/multipathd/Makefile
|
|
index 632b82b1..d053c1ed 100644
|
|
--- a/multipathd/Makefile
|
|
+++ b/multipathd/Makefile
|
|
@@ -30,7 +30,7 @@ ifeq ($(ENABLE_DMEVENTS_POLL),0)
|
|
endif
|
|
|
|
OBJS = main.o pidfile.o uxlsnr.o uxclnt.o cli.o cli_handlers.o waiter.o \
|
|
- dmevents.o
|
|
+ dmevents.o init_unwinder.o
|
|
|
|
EXEC = multipathd
|
|
|
|
diff --git a/multipathd/init_unwinder.c b/multipathd/init_unwinder.c
|
|
new file mode 100644
|
|
index 00000000..14467f3d
|
|
--- /dev/null
|
|
+++ b/multipathd/init_unwinder.c
|
|
@@ -0,0 +1,34 @@
|
|
+#include <pthread.h>
|
|
+#include <unistd.h>
|
|
+#include "init_unwinder.h"
|
|
+
|
|
+static pthread_mutex_t dummy_mtx = PTHREAD_MUTEX_INITIALIZER;
|
|
+static pthread_cond_t dummy_cond = PTHREAD_COND_INITIALIZER;
|
|
+
|
|
+static void *dummy_thread(void *arg __attribute__((unused)))
|
|
+{
|
|
+ pthread_mutex_lock(&dummy_mtx);
|
|
+ pthread_cond_broadcast(&dummy_cond);
|
|
+ pthread_mutex_unlock(&dummy_mtx);
|
|
+ pause();
|
|
+ return NULL;
|
|
+}
|
|
+
|
|
+int init_unwinder(void)
|
|
+{
|
|
+ pthread_t dummy;
|
|
+ int rc;
|
|
+
|
|
+ pthread_mutex_lock(&dummy_mtx);
|
|
+
|
|
+ rc = pthread_create(&dummy, NULL, dummy_thread, NULL);
|
|
+ if (rc != 0) {
|
|
+ pthread_mutex_unlock(&dummy_mtx);
|
|
+ return rc;
|
|
+ }
|
|
+
|
|
+ pthread_cond_wait(&dummy_cond, &dummy_mtx);
|
|
+ pthread_mutex_unlock(&dummy_mtx);
|
|
+
|
|
+ return pthread_cancel(dummy);
|
|
+}
|
|
diff --git a/multipathd/init_unwinder.h b/multipathd/init_unwinder.h
|
|
new file mode 100644
|
|
index 00000000..ada09f82
|
|
--- /dev/null
|
|
+++ b/multipathd/init_unwinder.h
|
|
@@ -0,0 +1,21 @@
|
|
+#ifndef _INIT_UNWINDER_H
|
|
+#define _INIT_UNWINDER_H 1
|
|
+
|
|
+/*
|
|
+ * init_unwinder(): make sure unwinder symbols are loaded
|
|
+ *
|
|
+ * libc's implementation of pthread_cancel() loads symbols from
|
|
+ * libgcc_s.so using dlopen() when pthread_cancel() is called
|
|
+ * for the first time. This happens even with LD_BIND_NOW=1.
|
|
+ * This may imply the need for file system access when a thread is
|
|
+ * cancelled, which in the case of multipath-tools might be in a
|
|
+ * dangerous situation where multipathd must avoid blocking.
|
|
+ *
|
|
+ * Call load_unwinder() during startup to make sure the dynamic
|
|
+ * linker has all necessary symbols resolved early on.
|
|
+ *
|
|
+ * Return: 0 if successful, an error number otherwise.
|
|
+ */
|
|
+int init_unwinder(void);
|
|
+
|
|
+#endif
|
|
diff --git a/multipathd/main.c b/multipathd/main.c
|
|
index 99a89a69..6f851ae8 100644
|
|
--- a/multipathd/main.c
|
|
+++ b/multipathd/main.c
|
|
@@ -83,6 +83,7 @@
|
|
#include "wwids.h"
|
|
#include "foreign.h"
|
|
#include "../third-party/valgrind/drd.h"
|
|
+#include "init_unwinder.h"
|
|
|
|
#define FILE_NAME_SIZE 256
|
|
#define CMDSIZE 160
|
|
@@ -3041,6 +3042,7 @@ child (__attribute__((unused)) void *param)
|
|
enum daemon_status state;
|
|
int exit_code = 1;
|
|
|
|
+ init_unwinder();
|
|
mlockall(MCL_CURRENT | MCL_FUTURE);
|
|
signal_init();
|
|
mp_rcu_data = setup_rcu();
|