[CRIU] [PATCH RFC] parasite: don't daemonize non-leader threads
Andrey Vagin
avagin at openvz.org
Fri May 24 17:33:55 EDT 2013
For dumping thread we need to execute only one command, so its
demonization is overload.
This patch blocks all signals and dumps all thread related parameters in
PARASITE_CMD_INIT_THREAD, then registers are dumped for this thread and
the last step is unblocking thread signals.
This patch simplifies a parasite code, because it removes execution of
commands for threads.
Don't commit this patch. It's just proof of concept.
Thanks Pavel for this idea.
Signed-off-by: Andrey Vagin <avagin at openvz.org>
---
include/parasite-syscall.h | 7 +-
include/parasite.h | 4 +-
parasite-syscall.c | 212 +++++++++++++++++++--------------------------
pie/parasite.c | 197 ++++++++++-------------------------------
4 files changed, 140 insertions(+), 280 deletions(-)
diff --git a/include/parasite-syscall.h b/include/parasite-syscall.h
index 3babeb8..2f29ce3 100644
--- a/include/parasite-syscall.h
+++ b/include/parasite-syscall.h
@@ -12,12 +12,9 @@ struct parasite_thread_ctl
bool daemonized;
- k_rtsigset_t sig_blocked;
bool use_sig_blocked;
void *rstack;
- struct rt_sigframe *sigframe;
- struct rt_sigframe *rsigframe; /* address in a parasite */
};
/* parasite control block */
@@ -39,6 +36,10 @@ struct parasite_ctl {
struct list_head pre_list;
struct page_pipe *mem_pp;
+ k_rtsigset_t sig_blocked;
+ struct rt_sigframe *sigframe;
+ struct rt_sigframe *rsigframe; /* address in a parasite */
+
int nr_threads;
struct parasite_thread_ctl threads[0];
};
diff --git a/include/parasite.h b/include/parasite.h
index d26b130..3b54fea 100644
--- a/include/parasite.h
+++ b/include/parasite.h
@@ -72,8 +72,6 @@ struct parasite_init_args {
int p_addr_len;
struct sockaddr_un p_addr;
- int nr_threads;
-
k_rtsigset_t sig_blocked;
struct rt_sigframe *sigframe;
@@ -152,7 +150,7 @@ struct parasite_dump_thread {
int id;
unsigned int *tid_addr;
pid_t tid;
- k_rtsigset_t blocked;
+ k_rtsigset_t sig_blocked;
u32 tls;
};
diff --git a/parasite-syscall.c b/parasite-syscall.c
index f44f406..3b91be1 100644
--- a/parasite-syscall.c
+++ b/parasite-syscall.c
@@ -388,8 +388,7 @@ static int parasite_init(struct parasite_ctl *ctl, pid_t pid, int nr_threads)
pr_info("Putting tsock into pid %d\n", pid);
args->h_addr_len = gen_parasite_saddr(&args->h_addr, getpid());
args->p_addr_len = gen_parasite_saddr(&args->p_addr, pid);
- args->nr_threads = nr_threads;
- args->sigframe = ctl->threads[0].rsigframe;
+ args->sigframe = ctl->rsigframe;
args->id = 0;
if (sock == -1) {
@@ -437,7 +436,7 @@ static int parasite_init(struct parasite_ctl *ctl, pid_t pid, int nr_threads)
goto err;
}
- ctl->threads[0].sig_blocked = args->sig_blocked;
+ ctl->sig_blocked = args->sig_blocked;
ctl->threads[0].use_sig_blocked = true;
if (connect(sock, (struct sockaddr *)&args->p_addr, args->p_addr_len) < 0) {
@@ -499,12 +498,49 @@ int parasite_dump_thread_seized(struct parasite_ctl *ctl, int id,
struct pid *tid, CoreEntry *core)
{
struct parasite_dump_thread *args;
+ pid_t pid = tid->real;
int ret;
args = parasite_args(ctl, struct parasite_dump_thread);
args->id = id;
- ret = parasite_execute_daemon_by_id(PARASITE_CMD_DUMP_THREAD, ctl, id);
+ if (id == 0)
+ ret = parasite_execute_daemon_by_id(PARASITE_CMD_DUMP_THREAD, ctl, id);
+ else {
+ user_regs_struct_t *regs_orig = &ctl->threads[id].regs_orig;
+ ctl->threads[id].tid = pid;
+
+ args->id = id;
+
+ ret = ptrace(PTRACE_GETREGS, pid, NULL, regs_orig);
+ if (ret) {
+ pr_perror("Can't obtain registers (pid: %d)", pid);
+ return -1;
+ }
+
+ ret = parasite_execute_trap_by_id(PARASITE_CMD_INIT_THREAD, ctl, id);
+ if (ret) {
+ pr_err("Can't init thread in parasite %d\n", pid);
+ return -1;
+ }
+
+ ctl->threads[id].use_sig_blocked = true;
+
+ ret = get_task_regs(pid, *regs_orig, core);
+ if (ret)
+ pr_err("Can't obtain regs for thread %d\n", pid);
+
+ if (parasite_execute_trap_by_id(PARASITE_CMD_FINI_THREAD, ctl, id)) {
+ pr_err("Can't init thread in parasite %d\n", pid);
+ return -1;
+ }
+ if (ret)
+ return -1;
+
+ memcpy(&core->thread_core->blk_sigset,
+ &args->sig_blocked, sizeof(k_rtsigset_t));
+ core->thread_core->has_blk_sigset = true;
+ }
CORE_THREAD_ARCH_INFO(core)->clear_tid_addr = encode_pointer(args->tid_addr);
tid->virt = args->tid;
@@ -793,85 +829,33 @@ int parasite_get_proc_fd_seized(struct parasite_ctl *ctl)
return fd;
}
-int parasite_init_threads_seized(struct parasite_ctl *ctl, struct pstree_item *item)
-{
- struct parasite_init_args *args;
- int ret = 0, i;
-
- args = parasite_args(ctl, struct parasite_init_args);
-
- for (i = 1; i < item->nr_threads; i++) {
- pid_t tid = item->threads[i].real;
- user_regs_struct_t *regs_orig = &ctl->threads[i].regs_orig;
-
- ctl->threads[i].tid = tid;
- ctl->nr_threads++;
-
- args->id = i;
- args->sigframe = ctl->threads[i].rsigframe;
-
- ret = ptrace(PTRACE_GETREGS, tid, NULL, regs_orig);
- if (ret) {
- pr_perror("Can't obtain registers (pid: %d)", tid);
- goto err;
- }
-
- ret = parasite_execute_trap_by_id(PARASITE_CMD_INIT_THREAD, ctl, i);
- if (ret) {
- pr_err("Can't init thread in parasite %d\n", tid);
- goto err;
- }
-
- ret = get_task_regs(tid, *regs_orig, item->core[i]);
- if (ret) {
- pr_err("Can't obtain regs for thread %d\n", tid);
- goto err;
- }
-
- ctl->threads[i].sig_blocked = args->sig_blocked;
- ctl->threads[i].use_sig_blocked = true;
-
- if (parasite_daemonize(ctl, i))
- goto err;
- }
-
- return 0;
-err:
- return -1 ;
-}
-
static int parasite_fini_seized(struct parasite_ctl *ctl)
{
- int status, ret = 0, i, nr = 0, nr_dmnz = 0;
-
- /* Start to trace syscalls for each thread */
- for (i = 0; i < ctl->nr_threads; i++) {
- pid_t pid = ctl->threads[i].tid;
+ int status, ret = 0;
+ pid_t pid = ctl->threads[0].tid;
- if (!ctl->threads[i].daemonized)
- break;
-
- ptrace(PTRACE_INTERRUPT, pid, NULL, NULL);
+ if (!ctl->threads[0].daemonized)
+ return 0;
- pr_debug("Waiting for %d to trap\n", pid);
- if (wait4(pid, &status, __WALL, NULL) != pid) {
- pr_perror("Waited pid mismatch (pid: %d)", pid);
- return -1;
- }
+ /* Start to trace syscalls for each thread */
+ ptrace(PTRACE_INTERRUPT, pid, NULL, NULL);
- pr_debug("Daemon %d exited trapping\n", pid);
- if (!WIFSTOPPED(status)) {
- pr_err("Task is still running (pid: %d)\n", pid);
- return -1;
- }
+ pr_debug("Waiting for %d to trap\n", pid);
+ if (wait4(pid, &status, __WALL, NULL) != pid) {
+ pr_perror("Waited pid mismatch (pid: %d)", pid);
+ return -1;
+ }
- ret = ptrace(PTRACE_SYSCALL, pid, NULL, NULL);
- if (ret) {
- pr_perror("ptrace");
- return -1;
- }
+ pr_debug("Daemon %d exited trapping\n", pid);
+ if (!WIFSTOPPED(status)) {
+ pr_err("Task is still running (pid: %d)\n", pid);
+ return -1;
+ }
- nr_dmnz++;
+ ret = ptrace(PTRACE_SYSCALL, pid, NULL, NULL);
+ if (ret) {
+ pr_perror("ptrace");
+ return -1;
}
ret = __parasite_execute_daemon_by_id(PARASITE_CMD_FINI, ctl, 0, false);
@@ -902,11 +886,8 @@ static int parasite_fini_seized(struct parasite_ctl *ctl)
pr_debug("%d is going to execute the syscall %lx\n", pid, regs.orig_ax);
if (regs.orig_ax == __NR_rt_sigreturn) {
- nr++;
pr_debug("%d was stopped\n", pid);
- if (nr == nr_dmnz)
- break;
- continue;
+ break;
}
ret = ptrace(PTRACE_SYSCALL, pid, NULL, NULL);
@@ -917,30 +898,23 @@ static int parasite_fini_seized(struct parasite_ctl *ctl)
}
/* Stop all threads on the exit point from sys_rt_sigreturn */
- for (i = 0; i < ctl->nr_threads; i++) {
- pid_t pid = ctl->threads[i].tid;
-
- if (!ctl->threads[i].daemonized)
- break;
-
- ctl->threads[i].use_sig_blocked = false;
+ ctl->threads[0].use_sig_blocked = false;
- ret = ptrace(PTRACE_SYSCALL, pid, NULL, NULL);
- if (ret) {
- pr_perror("ptrace");
- return -1;
- }
+ ret = ptrace(PTRACE_SYSCALL, pid, NULL, NULL);
+ if (ret) {
+ pr_perror("ptrace");
+ return -1;
+ }
- if (wait4(pid, &status, __WALL, NULL) != pid) {
- pr_perror("wait4 failed");
- return -1;
- }
+ if (wait4(pid, &status, __WALL, NULL) != pid) {
+ pr_perror("wait4 failed");
+ return -1;
+ }
- pr_debug("Trap %d\n", pid);
- if (!WIFSTOPPED(status)) {
- pr_err("%d\n", status);
- return -1;
- }
+ pr_debug("Trap %d\n", pid);
+ if (!WIFSTOPPED(status)) {
+ pr_err("%d\n", status);
+ return -1;
}
return ret;
@@ -1128,7 +1102,7 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, struct pstree_item *item,
ctl->args_size = parasite_args_size(vma_area_list, dfds);
ret = parasite_map_exchange(ctl, parasite_size + ctl->args_size +
- item->nr_threads * RESTORE_STACK_SIGFRAME +
+ RESTORE_STACK_SIGFRAME +
item->nr_threads * PARASITE_STACK_SIZE);
if (ret)
goto err_restore;
@@ -1142,14 +1116,18 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, struct pstree_item *item,
ctl->addr_args = parasite_sym(ctl->local_map, __export_parasite_args);
p = parasite_size + ctl->args_size;
+
+ ctl->rsigframe = ctl->remote_map + p;
+ ctl->sigframe = ctl->local_map + p;
+
+ p += RESTORE_STACK_SIGFRAME;
+
for (i = 0; i < item->nr_threads; i++) {
struct parasite_thread_ctl *thread = &ctl->threads[i];
thread->rstack = ctl->remote_map + p;
- thread->rsigframe = ctl->remote_map + p + PARASITE_STACK_SIZE;
- thread->sigframe = ctl->local_map + p + PARASITE_STACK_SIZE;
- p += PARASITE_STACK_SIZE + RESTORE_STACK_SIGFRAME;
+ p += PARASITE_STACK_SIZE;
}
ret = parasite_init(ctl, pid, item->nr_threads);
@@ -1170,28 +1148,14 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, struct pstree_item *item,
goto err_restore;
}
- if (parasite_daemonize(ctl, 0))
- goto err_restore;
+ memcpy(&item->core[0]->tc->blk_sigset,
+ &ctl->sig_blocked, sizeof(k_rtsigset_t));
- ret = parasite_init_threads_seized(ctl, item);
- if (ret)
+ if (construct_sigframe(ctl->sigframe, ctl->rsigframe, item->core[0]))
goto err_restore;
- for (i = 0; i < item->nr_threads; i++) {
- struct parasite_thread_ctl *thread = &ctl->threads[i];
-
- if (i == 0)
- memcpy(&item->core[i]->tc->blk_sigset,
- &thread->sig_blocked, sizeof(k_rtsigset_t));
- else {
- memcpy(&item->core[i]->thread_core->blk_sigset,
- &thread->sig_blocked, sizeof(k_rtsigset_t));
- item->core[i]->thread_core->has_blk_sigset = true;
- }
-
- if (construct_sigframe(thread->sigframe, thread->rsigframe, item->core[i]))
- goto err_restore;
- }
+ if (parasite_daemonize(ctl, 0))
+ goto err_restore;
return ctl;
diff --git a/pie/parasite.c b/pie/parasite.c
index 3e01cc7..0a94895 100644
--- a/pie/parasite.c
+++ b/pie/parasite.c
@@ -20,22 +20,7 @@
static int tsock = -1;
-static struct tid_state_s {
- int id;
-
- futex_t cmd;
- int ret;
-
- struct rt_sigframe *sigframe;
-} *tid_state;
-
-static unsigned int nr_tid_state;
-static unsigned int next_tid_state;
-
-#define TID_STATE_SIZE(n) \
- (ALIGN(sizeof(struct tid_state_s) * n, PAGE_SIZE))
-
-#define thread_leader (&tid_state[0])
+static struct rt_sigframe *sigframe;
#ifndef SPLICE_F_GIFT
#define SPLICE_F_GIFT 0x08
@@ -192,17 +177,12 @@ static int dump_thread(struct parasite_dump_thread *args)
return 0;
}
-static int init_thread(struct parasite_init_args *args)
+static int init_thread(struct parasite_dump_thread *args)
{
k_rtsigset_t to_block;
+ pid_t tid = sys_gettid();
int ret;
- if (args->id != next_tid_state)
- return -EINVAL;
-
- if (next_tid_state >= nr_tid_state)
- return -ENOMEM;
-
ksigfillset(&to_block);
ret = sys_sigprocmask(SIG_SETMASK, &to_block,
&args->sig_blocked,
@@ -210,72 +190,60 @@ static int init_thread(struct parasite_init_args *args)
if (ret)
return -1;
- tid_state[next_tid_state].id = next_tid_state;
- tid_state[next_tid_state].sigframe = args->sigframe;
+ ret = sys_prctl(PR_GET_TID_ADDRESS, (unsigned long) &args->tid_addr, 0, 0, 0);
+ if (ret)
+ goto err;
- futex_set(&tid_state[next_tid_state].cmd, PARASITE_CMD_IDLE);
+ args->tid = tid;
+ args->tls = arch_get_tls();
- next_tid_state++;
return ret;
+err:
+ sys_sigprocmask(SIG_SETMASK, &args->sig_blocked,
+ NULL, sizeof(k_rtsigset_t));
+ return ret;
}
-static void __parasite_daemon_thread_ack(struct tid_state_s *s, int ret)
+static int fini_thread(struct parasite_dump_thread *args)
{
- s->ret = ret;
- futex_set_and_wake(&s->cmd, PARASITE_CMD_IDLE);
-}
-
-static int fini_thread(struct tid_state_s *s)
-{
- unsigned long new_sp;
-
- new_sp = (long)s->sigframe + SIGFRAME_OFFSET;
- pr_debug("%ld: new_sp=%lx ip %lx\n", sys_gettid(),
- new_sp, s->sigframe->uc.uc_mcontext.rip);
-
- __parasite_daemon_thread_ack(s, 0);
-
- ARCH_RT_SIGRETURN(new_sp);
-
- BUG();
-
- return 0;
+ return sys_sigprocmask(SIG_SETMASK, &args->sig_blocked,
+ NULL, sizeof(k_rtsigset_t));
}
static int init(struct parasite_init_args *args)
{
+ k_rtsigset_t to_block;
int ret;
- if (!args->nr_threads)
- return -EINVAL;
-
- tid_state = (void *)sys_mmap(NULL, TID_STATE_SIZE(args->nr_threads),
- PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS,
- -1, 0);
- if ((unsigned long)tid_state > TASK_SIZE)
- return -ENOMEM;
-
- nr_tid_state = args->nr_threads;
+ sigframe = args->sigframe;
- ret = init_thread(args);
- if (ret < 0)
- return ret;
+ ksigfillset(&to_block);
+ ret = sys_sigprocmask(SIG_SETMASK, &to_block,
+ &args->sig_blocked,
+ sizeof(k_rtsigset_t));
+ if (ret)
+ return -1;
tsock = sys_socket(PF_UNIX, SOCK_DGRAM, 0);
- if (tsock < 0)
- return tsock;
+ if (tsock < 0) {
+ ret = tsock;
+ goto err;
+ }
ret = sys_bind(tsock, (struct sockaddr *) &args->p_addr, args->p_addr_len);
if (ret < 0)
- return ret;
+ goto err;
ret = sys_connect(tsock, (struct sockaddr *)&args->h_addr, args->h_addr_len);
if (ret < 0)
- return ret;
+ goto err;
return 0;
+err:
+ sys_sigprocmask(SIG_SETMASK, &args->sig_blocked,
+ NULL, sizeof(k_rtsigset_t));
+ return ret;
}
static char proc_mountpoint[] = "proc.crtools";
@@ -467,80 +435,18 @@ static int __parasite_daemon_wait_msg(struct ctl_msg *m)
return -1;
}
-static int __parasite_daemon_thread_wait_cmd(struct tid_state_s *s)
-{
- futex_wait_while_eq(&s->cmd, PARASITE_CMD_IDLE);
- return futex_get(&s->cmd);
-}
-
-static void noinline __used
-__parasite_daemon_thread(void *args, struct tid_state_s *s)
-{
- pr_debug("Running daemon thread %d\n", s->id);
-
- /* Reply we're alive */
- if (__parasite_daemon_reply_ack(s->id, PARASITE_CMD_DAEMONIZE, 0))
- return;
-
- while (1) {
- int ret, cmd;
-
- cmd = __parasite_daemon_thread_wait_cmd(s);
-
- pr_debug("Command %d in daemon thread %d\n", cmd, s->id);
-
- switch (cmd) {
- case PARASITE_CMD_DUMP_THREAD:
- ret = dump_thread(args);
- break;
- case PARASITE_CMD_FINI_THREAD:
- fini_thread(s);
- return;
- default:
- pr_err("Unknown command in parasite daemon thread: %d\n", cmd);
- ret = -1;
- break;
- }
- __parasite_daemon_thread_ack(s, ret);
- }
-
- pr_err("The thread %d trys to escape!!!", s->id);
- BUG();
- return;
-}
-
-static int __parasite_execute_thread(struct ctl_msg *m)
-{
- struct tid_state_s *s = &tid_state[m->id];
-
- pr_debug("Wake thread %d daemon with command %d\n", s->id, m->cmd);
- futex_set_and_wake(&s->cmd, m->cmd);
-
- pr_debug("Wait thread %d for PARASITE_CMD_IDLE\n", s->id);
- futex_wait_until(&s->cmd, PARASITE_CMD_IDLE);
-
- return s->ret;
-}
-
-static int fini(struct tid_state_s *s)
+static int fini()
{
unsigned long new_sp;
- int i;
-
- for (i = 1; i < next_tid_state; i++) {
- struct ctl_msg m = {.cmd = PARASITE_CMD_FINI_THREAD, .id = i};
- __parasite_execute_thread(&m);
- }
- new_sp = (long)s->sigframe + SIGFRAME_OFFSET;
+ pr_debug("xxx\n");
+ new_sp = (long)sigframe + SIGFRAME_OFFSET;
pr_debug("%ld: new_sp=%lx ip %lx\n", sys_gettid(),
- new_sp, s->sigframe->uc.uc_mcontext.rip);
+ new_sp, sigframe->uc.uc_mcontext.rip);
sys_close(tsock);
log_set_fd(-1);
- sys_munmap(tid_state, TID_STATE_SIZE(nr_tid_state));
-
ARCH_RT_SIGRETURN(new_sp);
BUG();
@@ -549,7 +455,7 @@ static int fini(struct tid_state_s *s)
}
static void noinline __used
-__parasite_daemon_thread_leader(void *args, struct tid_state_s *s)
+__parasite_daemon_thread_leader(void *args)
{
struct ctl_msg m = { };
int ret = -1;
@@ -566,17 +472,14 @@ __parasite_daemon_thread_leader(void *args, struct tid_state_s *s)
switch (m.cmd) {
case PARASITE_CMD_FINI:
- ret = fini(s);
- sys_close(tsock);
+ pr_debug("xxx\n");
+ fini();
/*
* No ACK here since we're getting out.
*/
break;
- case PARASITE_CMD_FINI_THREAD:
- ret = __parasite_execute_thread(&m);
- break;
case PARASITE_CMD_DUMP_THREAD:
- ret = __parasite_execute_thread(&m);
+ ret = dump_thread(args);
break;
case PARASITE_CMD_DUMPPAGES:
ret = dump_pages(args);
@@ -619,26 +522,18 @@ __parasite_daemon_thread_leader(void *args, struct tid_state_s *s)
}
out:
- fini(&tid_state[0]);
+ fini();
return;
}
static int noinline parasite_daemon(struct parasite_init_args *args)
{
- struct tid_state_s *s;
- bool is_leader = (args->id == 0);
-
- s = &tid_state[args->id];
-
- pr_info("Parasite entering daemon mode for %d\n", s->id);
+ pr_info("Parasite entering daemon mode\n");
- if (is_leader)
- __parasite_daemon_thread_leader(args, s);
- else
- __parasite_daemon_thread(args, s);
+ __parasite_daemon_thread_leader(args);
- pr_info("Parasite leaving daemon mode for %d\n", s->id);
+ pr_info("Parasite leaving daemon mode\n");
return 0;
}
@@ -652,6 +547,8 @@ int __used parasite_service(unsigned int cmd, void *args)
return init(args);
case PARASITE_CMD_INIT_THREAD:
return init_thread(args);
+ case PARASITE_CMD_FINI_THREAD:
+ return fini_thread(args);
case PARASITE_CMD_CFG_LOG:
return parasite_cfg_log(args);
case PARASITE_CMD_DAEMONIZE:
--
1.8.2
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