Merge tag 'seccomp-next' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into next

Author: James Morris

kernel/seccomp.c

@@ -13,7 +13,7 @@
  *        of Berkeley Packet Filters/Linux Socket Filters.
  */
 
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 #include <linux/audit.h>
 #include <linux/compat.h>
 #include <linux/coredump.h>
@@ -56,7 +56,7 @@
  * to a task_struct (other than @usage).
  */
 struct seccomp_filter {
-	atomic_t usage;
+	refcount_t usage;
 	struct seccomp_filter *prev;
 	struct bpf_prog *prog;
 };
@@ -378,7 +378,7 @@ static struct seccomp_filter *seccomp_prepare_filter(struct sock_fprog *fprog)
 		return ERR_PTR(ret);
 	}
 
-	atomic_set(&sfilter->usage, 1);
+	refcount_set(&sfilter->usage, 1);
 
 	return sfilter;
 }
@@ -465,7 +465,7 @@ void get_seccomp_filter(struct task_struct *tsk)
 	if (!orig)
 		return;
 	/* Reference count is bounded by the number of total processes. */
-	atomic_inc(&orig->usage);
+	refcount_inc(&orig->usage);
 }
 
 static inline void seccomp_filter_free(struct seccomp_filter *filter)
@@ -481,7 +481,7 @@ void put_seccomp_filter(struct task_struct *tsk)
 {
 	struct seccomp_filter *orig = tsk->seccomp.filter;
 	/* Clean up single-reference branches iteratively. */
-	while (orig && atomic_dec_and_test(&orig->usage)) {
+	while (orig && refcount_dec_and_test(&orig->usage)) {
 		struct seccomp_filter *freeme = orig;
 		orig = orig->prev;
 		seccomp_filter_free(freeme);
@@ -641,11 +641,12 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
 		return 0;
 
 	case SECCOMP_RET_KILL:
-	default: {
-		siginfo_t info;
+	default:
 		audit_seccomp(this_syscall, SIGSYS, action);
 		/* Dump core only if this is the last remaining thread. */
 		if (get_nr_threads(current) == 1) {
+			siginfo_t info;
+
 			/* Show the original registers in the dump. */
 			syscall_rollback(current, task_pt_regs(current));
 			/* Trigger a manual coredump since do_exit skips it. */
@@ -654,7 +655,6 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
 		}
 		do_exit(SIGSYS);
 	}
-	}
 
 	unreachable();
 

tools/testing/selftests/seccomp/seccomp_bpf.c

@@ -1822,6 +1822,23 @@ struct tsync_sibling {
 	struct __test_metadata *metadata;
 };
 
+/*
+ * To avoid joining joined threads (which is not allowed by Bionic),
+ * make sure we both successfully join and clear the tid to skip a
+ * later join attempt during fixture teardown. Any remaining threads
+ * will be directly killed during teardown.
+ */
+#define PTHREAD_JOIN(tid, status)					\
+	do {								\
+		int _rc = pthread_join(tid, status);			\
+		if (_rc) {						\
+			TH_LOG("pthread_join of tid %u failed: %d\n",	\
+				(unsigned int)tid, _rc);		\
+		} else {						\
+			tid = 0;					\
+		}							\
+	} while (0)
+
 FIXTURE_DATA(TSYNC) {
 	struct sock_fprog root_prog, apply_prog;
 	struct tsync_sibling sibling[TSYNC_SIBLINGS];
@@ -1890,14 +1907,14 @@ FIXTURE_TEARDOWN(TSYNC)
 
 	for ( ; sib < self->sibling_count; ++sib) {
 		struct tsync_sibling *s = &self->sibling[sib];
-		void *status;
 
 		if (!s->tid)
 			continue;
-		if (pthread_kill(s->tid, 0)) {
-			pthread_cancel(s->tid);
-			pthread_join(s->tid, &status);
-		}
+		/*
+		 * If a thread is still running, it may be stuck, so hit
+		 * it over the head really hard.
+		 */
+		pthread_kill(s->tid, 9);
 	}
 	pthread_mutex_destroy(&self->mutex);
 	pthread_cond_destroy(&self->cond);
@@ -1987,9 +2004,9 @@ TEST_F(TSYNC, siblings_fail_prctl)
 	pthread_mutex_unlock(&self->mutex);
 
 	/* Ensure diverging sibling failed to call prctl. */
-	pthread_join(self->sibling[0].tid, &status);
+	PTHREAD_JOIN(self->sibling[0].tid, &status);
 	EXPECT_EQ(SIBLING_EXIT_FAILURE, (long)status);
-	pthread_join(self->sibling[1].tid, &status);
+	PTHREAD_JOIN(self->sibling[1].tid, &status);
 	EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status);
 }
 
@@ -2029,9 +2046,9 @@ TEST_F(TSYNC, two_siblings_with_ancestor)
 	}
 	pthread_mutex_unlock(&self->mutex);
 	/* Ensure they are both killed and don't exit cleanly. */
-	pthread_join(self->sibling[0].tid, &status);
+	PTHREAD_JOIN(self->sibling[0].tid, &status);
 	EXPECT_EQ(0x0, (long)status);
-	pthread_join(self->sibling[1].tid, &status);
+	PTHREAD_JOIN(self->sibling[1].tid, &status);
 	EXPECT_EQ(0x0, (long)status);
 }
 
@@ -2055,9 +2072,9 @@ TEST_F(TSYNC, two_sibling_want_nnp)
 	pthread_mutex_unlock(&self->mutex);
 
 	/* Ensure they are both upset about lacking nnp. */
-	pthread_join(self->sibling[0].tid, &status);
+	PTHREAD_JOIN(self->sibling[0].tid, &status);
 	EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status);
-	pthread_join(self->sibling[1].tid, &status);
+	PTHREAD_JOIN(self->sibling[1].tid, &status);
 	EXPECT_EQ(SIBLING_EXIT_NEWPRIVS, (long)status);
 }
 
@@ -2095,9 +2112,9 @@ TEST_F(TSYNC, two_siblings_with_no_filter)
 	pthread_mutex_unlock(&self->mutex);
 
 	/* Ensure they are both killed and don't exit cleanly. */
-	pthread_join(self->sibling[0].tid, &status);
+	PTHREAD_JOIN(self->sibling[0].tid, &status);
 	EXPECT_EQ(0x0, (long)status);
-	pthread_join(self->sibling[1].tid, &status);
+	PTHREAD_JOIN(self->sibling[1].tid, &status);
 	EXPECT_EQ(0x0, (long)status);
 }
 
@@ -2140,9 +2157,9 @@ TEST_F(TSYNC, two_siblings_with_one_divergence)
 	pthread_mutex_unlock(&self->mutex);
 
 	/* Ensure they are both unkilled. */
-	pthread_join(self->sibling[0].tid, &status);
+	PTHREAD_JOIN(self->sibling[0].tid, &status);
 	EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status);
-	pthread_join(self->sibling[1].tid, &status);
+	PTHREAD_JOIN(self->sibling[1].tid, &status);
 	EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status);
 }
 
@@ -2199,7 +2216,7 @@ TEST_F(TSYNC, two_siblings_not_under_filter)
 		TH_LOG("cond broadcast non-zero");
 	}
 	pthread_mutex_unlock(&self->mutex);
-	pthread_join(self->sibling[sib].tid, &status);
+	PTHREAD_JOIN(self->sibling[sib].tid, &status);
 	EXPECT_EQ(SIBLING_EXIT_UNKILLED, (long)status);
 	/* Poll for actual task death. pthread_join doesn't guarantee it. */
 	while (!kill(self->sibling[sib].system_tid, 0))
@@ -2224,7 +2241,7 @@ TEST_F(TSYNC, two_siblings_not_under_filter)
 		TH_LOG("cond broadcast non-zero");
 	}
 	pthread_mutex_unlock(&self->mutex);
-	pthread_join(self->sibling[sib].tid, &status);
+	PTHREAD_JOIN(self->sibling[sib].tid, &status);
 	EXPECT_EQ(0, (long)status);
 	/* Poll for actual task death. pthread_join doesn't guarantee it. */
 	while (!kill(self->sibling[sib].system_tid, 0))