git: b8534da5ee54 - stable/13 - REAP_KILL_PROC: kill processes in the threaded taskqueue context
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Date: Sat, 03 Sep 2022 01:29:24 UTC
The branch stable/13 has been updated by kib:
URL: https://cgit.FreeBSD.org/src/commit/?id=b8534da5ee54c75259dbbf8b5e54b0f261940714
commit b8534da5ee54c75259dbbf8b5e54b0f261940714
Author: Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2022-08-12 19:37:08 +0000
Commit: Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2022-09-03 01:17:36 +0000
REAP_KILL_PROC: kill processes in the threaded taskqueue context
(cherry picked from commit 2842ec6d99ce3590eabb34d23eff5b0fed24eb98)
---
sys/kern/kern_procctl.c | 183 ++++++++++++++++++++++++++++++++----------------
1 file changed, 124 insertions(+), 59 deletions(-)
diff --git a/sys/kern/kern_procctl.c b/sys/kern/kern_procctl.c
index 36372fd31bd4..1fb1183741d6 100644
--- a/sys/kern/kern_procctl.c
+++ b/sys/kern/kern_procctl.c
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
#include <sys/sx.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
+#include <sys/taskqueue.h>
#include <sys/wait.h>
#include <vm/vm.h>
@@ -243,32 +244,29 @@ reap_getpids(struct thread *td, struct proc *p, void *data)
return (error);
}
-static void
-reap_kill_proc_relock(struct proc *p, int xlocked)
-{
- PROC_UNLOCK(p);
- if (xlocked)
- sx_xlock(&proctree_lock);
- else
- sx_slock(&proctree_lock);
- PROC_LOCK(p);
-}
+struct reap_kill_proc_work {
+ struct ucred *cr;
+ struct proc *target;
+ ksiginfo_t *ksi;
+ struct procctl_reaper_kill *rk;
+ int *error;
+ struct task t;
+};
static void
-reap_kill_proc_locked(struct thread *td, struct proc *p2,
- ksiginfo_t *ksi, struct procctl_reaper_kill *rk, int *error)
+reap_kill_proc_locked(struct reap_kill_proc_work *w)
{
- int error1, r, xlocked;
+ int error1;
bool need_stop;
- PROC_LOCK_ASSERT(p2, MA_OWNED);
- PROC_ASSERT_HELD(p2);
+ PROC_LOCK_ASSERT(w->target, MA_OWNED);
+ PROC_ASSERT_HELD(w->target);
- error1 = p_cansignal(td, p2, rk->rk_sig);
+ error1 = cr_cansignal(w->cr, w->target, w->rk->rk_sig);
if (error1 != 0) {
- if (*error == ESRCH) {
- rk->rk_fpid = p2->p_pid;
- *error = error1;
+ if (*w->error == ESRCH) {
+ w->rk->rk_fpid = w->target->p_pid;
+ *w->error = error1;
}
return;
}
@@ -286,39 +284,34 @@ reap_kill_proc_locked(struct thread *td, struct proc *p2,
* thread signals the whole subtree, it is an application
* race.
*/
- need_stop = p2 != td->td_proc &&
- (td->td_proc->p_flag2 & P2_WEXIT) == 0 &&
- (p2->p_flag & (P_KPROC | P_SYSTEM | P_STOPPED)) == 0 &&
- (rk->rk_flags & REAPER_KILL_CHILDREN) == 0;
-
- if (need_stop) {
- xlocked = sx_xlocked(&proctree_lock);
- sx_unlock(&proctree_lock);
- r = thread_single(p2, SINGLE_ALLPROC);
- reap_kill_proc_relock(p2, xlocked);
- if (r != 0)
- need_stop = false;
- }
+ if ((w->target->p_flag & (P_KPROC | P_SYSTEM | P_STOPPED)) == 0)
+ need_stop = thread_single(w->target, SINGLE_ALLPROC) == 0;
+ else
+ need_stop = false;
- pksignal(p2, rk->rk_sig, ksi);
- rk->rk_killed++;
- *error = error1;
+ (void)pksignal(w->target, w->rk->rk_sig, w->ksi);
+ w->rk->rk_killed++;
+ *w->error = error1;
if (need_stop)
- thread_single_end(p2, SINGLE_ALLPROC);
+ thread_single_end(w->target, SINGLE_ALLPROC);
}
static void
-reap_kill_proc(struct thread *td, struct proc *p2, ksiginfo_t *ksi,
- struct procctl_reaper_kill *rk, int *error)
+reap_kill_proc_work(void *arg, int pending __unused)
{
- PROC_LOCK(p2);
- if ((p2->p_flag2 & P2_WEXIT) == 0) {
- _PHOLD_LITE(p2);
- reap_kill_proc_locked(td, p2, ksi, rk, error);
- _PRELE(p2);
- }
- PROC_UNLOCK(p2);
+ struct reap_kill_proc_work *w;
+
+ w = arg;
+ PROC_LOCK(w->target);
+ if ((w->target->p_flag2 & P2_WEXIT) == 0)
+ reap_kill_proc_locked(w);
+ PROC_UNLOCK(w->target);
+
+ sx_xlock(&proctree_lock);
+ w->target = NULL;
+ wakeup(&w->target);
+ sx_xunlock(&proctree_lock);
}
struct reap_kill_tracker {
@@ -357,25 +350,40 @@ reap_kill_children(struct thread *td, struct proc *reaper,
struct procctl_reaper_kill *rk, ksiginfo_t *ksi, int *error)
{
struct proc *p2;
+ int error1;
LIST_FOREACH(p2, &reaper->p_children, p_sibling) {
- (void)reap_kill_proc(td, p2, ksi, rk, error);
- /*
- * Do not end the loop on error, signal everything we
- * can.
- */
+ PROC_LOCK(p2);
+ if ((p2->p_flag2 & P2_WEXIT) == 0) {
+ error1 = p_cansignal(td, p2, rk->rk_sig);
+ if (error1 != 0) {
+ if (*error == ESRCH) {
+ rk->rk_fpid = p2->p_pid;
+ *error = error1;
+ }
+
+ /*
+ * Do not end the loop on error,
+ * signal everything we can.
+ */
+ } else {
+ (void)pksignal(p2, rk->rk_sig, ksi);
+ rk->rk_killed++;
+ }
+ }
+ PROC_UNLOCK(p2);
}
}
static bool
reap_kill_subtree_once(struct thread *td, struct proc *p, struct proc *reaper,
- struct procctl_reaper_kill *rk, ksiginfo_t *ksi, int *error,
- struct unrhdr *pids)
+ struct unrhdr *pids, struct reap_kill_proc_work *w)
{
struct reap_kill_tracker_head tracker;
struct reap_kill_tracker *t;
struct proc *p2;
- bool res;
+ int r, xlocked;
+ bool res, st;
res = false;
TAILQ_INIT(&tracker);
@@ -397,14 +405,54 @@ reap_kill_subtree_once(struct thread *td, struct proc *p, struct proc *reaper,
LIST_FOREACH(p2, &t->parent->p_reaplist, p_reapsibling) {
if (t->parent == reaper &&
- (rk->rk_flags & REAPER_KILL_SUBTREE) != 0 &&
- p2->p_reapsubtree != rk->rk_subtree)
+ (w->rk->rk_flags & REAPER_KILL_SUBTREE) != 0 &&
+ p2->p_reapsubtree != w->rk->rk_subtree)
continue;
if ((p2->p_treeflag & P_TREE_REAPER) != 0)
reap_kill_sched(&tracker, p2);
if (alloc_unr_specific(pids, p2->p_pid) != p2->p_pid)
continue;
- reap_kill_proc(td, p2, ksi, rk, error);
+ if (p2 == td->td_proc) {
+ if ((p2->p_flag & P_HADTHREADS) != 0 &&
+ (p2->p_flag2 & P2_WEXIT) == 0) {
+ xlocked = sx_xlocked(&proctree_lock);
+ sx_unlock(&proctree_lock);
+ st = true;
+ } else {
+ st = false;
+ }
+ PROC_LOCK(p2);
+ if (st)
+ r = thread_single(p2, SINGLE_NO_EXIT);
+ (void)pksignal(p2, w->rk->rk_sig, w->ksi);
+ w->rk->rk_killed++;
+ if (st && r == 0)
+ thread_single_end(p2, SINGLE_NO_EXIT);
+ PROC_UNLOCK(p2);
+ if (st) {
+ if (xlocked)
+ sx_xlock(&proctree_lock);
+ else
+ sx_slock(&proctree_lock);
+ }
+ } else {
+ PROC_LOCK(p2);
+ if ((p2->p_flag2 & P2_WEXIT) == 0) {
+ _PHOLD_LITE(p2);
+ PROC_UNLOCK(p2);
+ w->target = p2;
+ taskqueue_enqueue(taskqueue_thread,
+ &w->t);
+ while (w->target != NULL) {
+ sx_sleep(&w->target,
+ &proctree_lock, PWAIT,
+ "reapst", 0);
+ }
+ PROC_LOCK(p2);
+ _PRELE(p2);
+ }
+ PROC_UNLOCK(p2);
+ }
res = true;
}
reap_kill_sched_free(t);
@@ -414,7 +462,7 @@ reap_kill_subtree_once(struct thread *td, struct proc *p, struct proc *reaper,
static void
reap_kill_subtree(struct thread *td, struct proc *p, struct proc *reaper,
- struct procctl_reaper_kill *rk, ksiginfo_t *ksi, int *error)
+ struct reap_kill_proc_work *w)
{
struct unrhdr pids;
@@ -431,7 +479,7 @@ reap_kill_subtree(struct thread *td, struct proc *p, struct proc *reaper,
}
td->td_proc->p_singlethr++;
PROC_UNLOCK(td->td_proc);
- while (reap_kill_subtree_once(td, p, reaper, rk, ksi, error, &pids))
+ while (reap_kill_subtree_once(td, p, reaper, &pids, w))
;
PROC_LOCK(td->td_proc);
td->td_proc->p_singlethr--;
@@ -455,6 +503,7 @@ reap_kill_sapblk(struct thread *td __unused, void *data)
static int
reap_kill(struct thread *td, struct proc *p, void *data)
{
+ struct reap_kill_proc_work w;
struct proc *reaper;
ksiginfo_t ksi;
struct procctl_reaper_kill *rk;
@@ -483,7 +532,23 @@ reap_kill(struct thread *td, struct proc *p, void *data)
if ((rk->rk_flags & REAPER_KILL_CHILDREN) != 0) {
reap_kill_children(td, reaper, rk, &ksi, &error);
} else {
- reap_kill_subtree(td, p, reaper, rk, &ksi, &error);
+ w.cr = crhold(td->td_ucred);
+ w.ksi = &ksi;
+ w.rk = rk;
+ w.error = &error;
+ TASK_INIT(&w.t, 0, reap_kill_proc_work, &w);
+
+ /*
+ * Prevent swapout, since w, ksi, and possibly rk, are
+ * allocated on the stack. We sleep in
+ * reap_kill_subtree_once() waiting for task to
+ * complete single-threading.
+ */
+ PHOLD(td->td_proc);
+
+ reap_kill_subtree(td, p, reaper, &w);
+ PRELE(td->td_proc);
+ crfree(w.cr);
}
PROC_LOCK(p);
return (error);