[src/trunk]: src/sys/compat/linux/common Fix proc / lwp lookup processing in ...

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/6fb74b5b0567
branches:  trunk
changeset: 931695:6fb74b5b0567
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Wed Apr 29 01:55:18 2020 +0000

description:
Fix proc / lwp lookup processing in linux_sys_sched_getaffinity()
and linux_sys_sched_setaffinity().  They were incorrect even before
the LWP ID changes, but those changes exposed the latent bugs.

diffstat:

 sys/compat/linux/common/linux_sched.c |  46 ++++++++++++++++++++++++++--------
 1 files changed, 35 insertions(+), 11 deletions(-)

diffs (96 lines):

diff -r 8debe6daa9ea -r 6fb74b5b0567 sys/compat/linux/common/linux_sched.c
--- a/sys/compat/linux/common/linux_sched.c     Wed Apr 29 01:53:48 2020 +0000
+++ b/sys/compat/linux/common/linux_sched.c     Wed Apr 29 01:55:18 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_sched.c,v 1.75 2020/04/24 03:22:06 thorpej Exp $ */
+/*     $NetBSD: linux_sched.c,v 1.76 2020/04/29 01:55:18 thorpej Exp $ */
 
 /*-
  * Copyright (c) 1999, 2019 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.75 2020/04/24 03:22:06 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.76 2020/04/29 01:55:18 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/mount.h>
@@ -608,6 +608,7 @@
                syscallarg(unsigned int) len;
                syscallarg(unsigned long *) mask;
        } */
+       struct proc *p;
        struct lwp *t;
        kcpuset_t *kcset;
        size_t size;
@@ -618,15 +619,23 @@
        if (SCARG(uap, len) < size)
                return EINVAL;
 
-       /* Lock the LWP */
-       t = lwp_find2(SCARG(uap, pid), l->l_lid);
-       if (t == NULL)
-               return ESRCH;
+       if (SCARG(uap, pid) == 0) {
+               p = curproc;
+               mutex_enter(p->p_lock);
+               t = curlwp;
+       } else {
+               t = lwp_find2(-1, SCARG(uap, pid));
+               if (__predict_false(t == NULL)) {
+                       return ESRCH;
+               }
+               p = t->l_proc;
+               KASSERT(mutex_owned(p->p_lock));
+       }
 
        /* Check the permission */
        if (kauth_authorize_process(l->l_cred,
-           KAUTH_PROCESS_SCHEDULER_GETAFFINITY, t->l_proc, NULL, NULL, NULL)) {
-               mutex_exit(t->l_proc->p_lock);
+           KAUTH_PROCESS_SCHEDULER_GETAFFINITY, p, NULL, NULL, NULL)) {
+               mutex_exit(p->p_lock);
                return EPERM;
        }
 
@@ -644,7 +653,7 @@
                        kcpuset_set(kcset, i);
        }
        lwp_unlock(t);
-       mutex_exit(t->l_proc->p_lock);
+       mutex_exit(p->p_lock);
        error = kcpuset_copyout(kcset, (cpuset_t *)SCARG(uap, mask), size);
        kcpuset_unuse(kcset, NULL);
        *retval = size;
@@ -661,13 +670,28 @@
        } */
        struct sys__sched_setaffinity_args ssa;
        size_t size;
+       pid_t pid;
 
        size = LINUX_CPU_MASK_SIZE;
        if (SCARG(uap, len) < size)
                return EINVAL;
 
-       SCARG(&ssa, pid) = SCARG(uap, pid);
-       SCARG(&ssa, lid) = l->l_lid;
+       if (SCARG(uap, pid) != 0) {
+               /* Get the canonical PID for the process. */
+               mutex_enter(proc_lock);
+               struct proc *p = proc_find_lwpid(SCARG(uap, pid));
+               if (p == NULL) {
+                       mutex_exit(proc_lock);
+                       return ESRCH;
+               }
+               pid = p->p_pid;
+               mutex_exit(proc_lock);
+       } else {
+               pid = 0;
+       }
+
+       SCARG(&ssa, pid) = pid;
+       SCARG(&ssa, lid) = SCARG(uap, pid);
        SCARG(&ssa, size) = size;
        SCARG(&ssa, cpuset) = (cpuset_t *)SCARG(uap, mask);