* Anjali Kulkarni anjali.k.kulkarni@oracle.com [241015 13:30]:
Test to check if setting PROC_CN_MCAST_NOTIFY in proc connector API, allows a thread's non-zero exit status to be returned to proc_filter.
The threads.c program creates 2 child threads. 1st thread handles signal SIGSEGV, and 2nd thread needs to indicate some error condition (value 1) to the kernel, instead of using pthread_exit() with 1.
In both cases, child sends notify_netlink_thread_exit(exit_code) to kernel, to let kernel know it has exited abnormally with exit_code.
Compile: make thread make proc_filter To see non-zero exit notifications, run: ./proc_filter -f Run threads code in another window: ./threads Note the 2 child thread IDs reported above Send SIGSEGV signal to the child handling SIGSEGV: kill -11 <child1-tid> Watch the child 1 tid being notified with exit code 11 to proc_filter Watch child 2 tid being notified with exit code 1 (value defined in code) to proc_filter
Signed-off-by: Anjali Kulkarni anjali.k.kulkarni@oracle.com
tools/testing/selftests/connector/Makefile | 23 +++- .../testing/selftests/connector/proc_filter.c | 5 + tools/testing/selftests/connector/thread.c | 116 ++++++++++++++++++ .../selftests/connector/thread_filter.c | 96 +++++++++++++++ 4 files changed, 239 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/connector/thread.c create mode 100644 tools/testing/selftests/connector/thread_filter.c
diff --git a/tools/testing/selftests/connector/Makefile b/tools/testing/selftests/connector/Makefile index 92188b9bac5c..bf335826bc3b 100644 --- a/tools/testing/selftests/connector/Makefile +++ b/tools/testing/selftests/connector/Makefile @@ -1,5 +1,26 @@ # SPDX-License-Identifier: GPL-2.0 -CFLAGS += -Wall $(KHDR_INCLUDES) +KERNEL="../../../.."
+CFLAGS += -Wall $(KHDR_INCLUDES) -I $(KERNEL)/include/uapi -I $(KERNEL)/include
+proc_filter: proc_filter.o
- cc proc_filter.o -o proc_filter
+proc_filter.o: proc_filter.c
- cc -c proc_filter.c -o proc_filter.o $(CFLAGS)
+thread: thread.o thread_filter.o
- cc thread.o thread_filter.o -o thread
+thread.o: thread.c $(DEPS)
cc -c thread.c -o thread.o $(CFLAGS)+thread_filter.o: thread_filter.c
cc -c thread_filter.c -o thread_filter.o $(CFLAGS)+define EXTRA_CLEAN
- rm *.o thread
+endef TEST_GEN_PROGS = proc_filter diff --git a/tools/testing/selftests/connector/proc_filter.c b/tools/testing/selftests/connector/proc_filter.c index 4a825b997666..6fb4842894f8 100644 --- a/tools/testing/selftests/connector/proc_filter.c +++ b/tools/testing/selftests/connector/proc_filter.c @@ -1,4 +1,9 @@ // SPDX-License-Identifier: GPL-2.0-only +/*
- Author: Anjali Kulkarni anjali.k.kulkarni@oracle.com
- Copyright (c) 2024 Oracle and/or its affiliates.
- */
#include <sys/types.h> #include <sys/epoll.h> diff --git a/tools/testing/selftests/connector/thread.c b/tools/testing/selftests/connector/thread.c new file mode 100644 index 000000000000..8c9abf6115d6 --- /dev/null +++ b/tools/testing/selftests/connector/thread.c @@ -0,0 +1,116 @@ +// SPDX-License-Identifier: GPL-2.0-only +/*
- Author: Anjali Kulkarni anjali.k.kulkarni@oracle.com
- Copyright (c) 2024 Oracle and/or its affiliates.
- */
+#include <pthread.h> +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <signal.h>
+/*
- This code tests a thread exit notification when thread exits abnormally.
- Normally, when a thread exits abnormally, the kernel is not aware of the
- exit code. This is usually only conveyed from child to parent via the
- pthread_exit() and pthread_join() calls. Sometimes, however, a parent
- process cannot monitor all child processes via pthread_join(), particularly
- when there is a huge amount of child processes. In this case, the parent
- has created the child with PTHREAD_CREATE_DETACHED attribute.
- To fix this problem, either when child wants to convey non-zero exit via
- pthread_exit() or in a signal handler, the child can notify the kernel's
- connector module it's exit status via a netlink call with new type
- PROC_CN_MCAST_NOTIFY. (Implemented in the thread_filter.c file).
- This will send the exit code from the child to the kernel, which the kernel
- can later return to proc_filter program when the child actually exits.
- To test this usecase:
- Compile:
- make thread
- make proc_filter
- To see non-zero exit notifications, run:
- ./proc_filter -f
- Start the threads code, creating 2 threads, in another window:
- ./threads
- Note the 2 child thread IDs reported above
- Send SIGSEGV signal to the child handling SIGSEGV:
- kill -11 <child1-tid>
- Watch the event being notified with exit code 11 to proc_filter
- Watch child 2 tid being notified with exit code 1 (value defined in code)
- to proc_filter
- */
+extern int notify_netlink_thread_exit(unsigned int exit_code);
+static void sigsegvh(int sig) +{
- unsigned int exit_code = (unsigned int) sig;
- /*
* Send any non-zero value to get a notification. Here we are* sending the signal number for SIGSEGV which is 11*/- notify_netlink_thread_exit(exit_code);
+}
+void *threadc1(void *ptr) +{
- signal(SIGSEGV, sigsegvh);
- printf("Child 1 thread id %d, handling SIGSEGV\n", gettid());
- sleep(20);
- pthread_exit(NULL);
+}
+void *threadc2(void *ptr) +{
- int exit_val = 1;
- printf("Child 2 thread id %d, wants to exit with value %d\n",
gettid(), exit_val);- sleep(2);
- notify_netlink_thread_exit(exit_val);
- pthread_exit(NULL);
+}
+int main(int argc, char **argv) +{
- pthread_t thread1, thread2;
- pthread_attr_t attr1, attr2;
- int ret;
- ret = pthread_attr_init(&attr1);
- if (ret != 0) {
perror("pthread_attr_init failed");exit(ret);- }
- ret = pthread_attr_setdetachstate(&attr1, PTHREAD_CREATE_DETACHED);
- if (ret != 0) {
perror("pthread_attr_setdetachstate failed");exit(ret);- }
- ret = pthread_create(&thread1, &attr1, *threadc1, NULL);
- if (ret != 0) {
perror("pthread_create failed");exit(ret);- }
- ret = pthread_attr_init(&attr2);
- if (ret != 0) {
perror("pthread_attr_init failed");exit(ret);- }
- ret = pthread_attr_setdetachstate(&attr2, PTHREAD_CREATE_DETACHED);
- if (ret != 0) {
perror("pthread_attr_setdetachstate failed");exit(ret);- }
- ret = pthread_create(&thread2, &attr2, *threadc2, NULL);
- if (ret != 0) {
perror("pthread_create failed");exit(ret);- }
I expected the test to check for the correct value to be returned? Could you use pthread_join() and verify the same value is returned through the new mechanism, or will they not match?
- /* Wait for children to exit or be killed */
- sleep(30);
- exit(0);
+} diff --git a/tools/testing/selftests/connector/thread_filter.c b/tools/testing/selftests/connector/thread_filter.c new file mode 100644 index 000000000000..3da740aa7537 --- /dev/null +++ b/tools/testing/selftests/connector/thread_filter.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0-only +/*
- Author: Anjali Kulkarni anjali.k.kulkarni@oracle.com
- Copyright (c) 2024 Oracle and/or its affiliates.
- */
+#include <sys/types.h> +#include <sys/epoll.h> +#include <sys/socket.h> +#include <linux/netlink.h> +#include <linux/connector.h> +#include <linux/cn_proc.h>
+#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <strings.h> +#include <errno.h> +#include <signal.h> +#include <string.h>
+#define NL_MESSAGE_SIZE (sizeof(struct nlmsghdr) + sizeof(struct cn_msg) + \
sizeof(struct proc_input))+/*
- Send PROC_CN_MCAST_NOTIFY type notification to the connector code in kernel.
- This will send the exit_code specified by user to the connector layer, so
- it can send a notification for that event to any listening process
- */
+int send_message(int nl_sock, unsigned int exit_code) +{
- char buff[NL_MESSAGE_SIZE];
- struct nlmsghdr *hdr;
- struct cn_msg *msg;
- hdr = (struct nlmsghdr *)buff;
- hdr->nlmsg_len = NL_MESSAGE_SIZE;
- hdr->nlmsg_type = NLMSG_DONE;
- hdr->nlmsg_flags = 0;
- hdr->nlmsg_seq = 0;
- hdr->nlmsg_pid = getpid();
- msg = (struct cn_msg *)NLMSG_DATA(hdr);
- msg->id.idx = CN_IDX_PROC;
- msg->id.val = CN_VAL_PROC;
- msg->seq = 0;
- msg->ack = 0;
- msg->flags = 0;
- msg->len = sizeof(struct proc_input);
- ((struct proc_input *)msg->data)->mcast_op =
PROC_CN_MCAST_NOTIFY;- ((struct proc_input *)msg->data)->uexit_code = exit_code;
- if (send(nl_sock, hdr, hdr->nlmsg_len, 0) == -1) {
perror("send failed");return -errno;- }
- return 0;
+}
+int notify_netlink_thread_exit(unsigned int exit_code) +{
- struct sockaddr_nl sa_nl;
- int err = 0;
- int nl_sock;
- nl_sock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
- if (nl_sock == -1) {
perror("socket failed");return -errno;- }
- bzero(&sa_nl, sizeof(sa_nl));
- sa_nl.nl_family = AF_NETLINK;
- sa_nl.nl_groups = CN_IDX_PROC;
- sa_nl.nl_pid = gettid();
- if (bind(nl_sock, (struct sockaddr *)&sa_nl, sizeof(sa_nl)) == -1) {
perror("bind failed");close(nl_sock);return -errno;- }
- err = send_message(nl_sock, exit_code);
- close(nl_sock);
- if (err < 0)
return err;- return 0;
+}
2.46.0