{"id":2227579,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2227579/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260424-master-v2-3-8b50b5c063ed@gmail.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.1/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260424-master-v2-3-8b50b5c063ed@gmail.com>","date":"2026-04-23T21:36:40","name":"[v2,3/3] tests/tcg: Add test for /proc/self/task/ filtering and tkill validation","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"7400837ae45219f219dd55b23178beaa94839485","submitter":{"id":93154,"url":"http://patchwork.ozlabs.org/api/1.1/people/93154/?format=json","name":"Ali Raza","email":"elirazamumtaz@gmail.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260424-master-v2-3-8b50b5c063ed@gmail.com/mbox/","series":[{"id":501265,"url":"http://patchwork.ozlabs.org/api/1.1/series/501265/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=501265","date":"2026-04-23T21:36:37","name":"linux-user: Filter /proc/*/task/ and validate tkill targets","version":2,"mbox":"http://patchwork.ozlabs.org/series/501265/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2227579/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2227579/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=UF1RupDW;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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charset=\"utf-8\"","Content-Transfer-Encoding":"7bit","Message-Id":"<20260424-master-v2-3-8b50b5c063ed@gmail.com>","References":"<20260424-master-v2-0-8b50b5c063ed@gmail.com>","In-Reply-To":"<20260424-master-v2-0-8b50b5c063ed@gmail.com>","To":"qemu-devel@nongnu.org","Cc":"Ali Raza , Laurent Vivier ,\n Pierrick Bouvier ,\n =?utf-8?q?Alex_Benn=C3=A9e?= , deller@gmx.de","X-Mailer":"b4 0.15.2","Received-SPF":"pass client-ip=2a00:1450:4864:20::430;\n envelope-from=elirazamumtaz@gmail.com; helo=mail-wr1-x430.google.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-Mailman-Approved-At":"Thu, 23 Apr 2026 20:42:33 -0400","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"Add a multiarch linux-user test that verifies:\n\n1. /proc/self/task/ only lists guest threads -- spawns NUM_THREADS\n pthreads, reads the task directory, and asserts every entry maps\n to a known guest TID and the total count matches.\n\n2. tkill(guest_tid, 0) succeeds for all guest threads.\n\n3. tkill to a non-guest TID returns ESRCH.\n\nOn native Linux this test trivially passes since there are no\nQEMU-internal threads. Under QEMU user-mode, it exercises the\ngetdents64 filtering and tkill validation added in the previous\ntwo commits.\n\nSigned-off-by: Ali Raza (@locus-x64)\n\n---\nChanges in v2:\n- Hard-assert ESRCH on tkill to a non-guest tid (was a printf).\n- Add tgkill coverage: success on guest tids; ESRCH on a wrong tgid.\n---\n tests/tcg/multiarch/Makefile.target | 2 +\n tests/tcg/multiarch/linux/linux-proc-task.c | 193 ++++++++++++++++++++++++++++\n 2 files changed, 195 insertions(+)","diff":"diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target\nindex 508149d57b..8d6e2af617 100644\n--- a/tests/tcg/multiarch/Makefile.target\n+++ b/tests/tcg/multiarch/Makefile.target\n@@ -39,6 +39,8 @@ testthread: LDFLAGS+=-lpthread\n \n threadcount: LDFLAGS+=-lpthread\n \n+linux-proc-task: LDFLAGS+=-lpthread\n+\n signals: LDFLAGS+=-lrt -lpthread\n \n munmap-pthread: CFLAGS+=-pthread\ndiff --git a/tests/tcg/multiarch/linux/linux-proc-task.c b/tests/tcg/multiarch/linux/linux-proc-task.c\nnew file mode 100644\nindex 0000000000..0c41a4443f\n--- /dev/null\n+++ b/tests/tcg/multiarch/linux/linux-proc-task.c\n@@ -0,0 +1,193 @@\n+/*\n+ * Test that /proc/self/task/ only lists guest threads.\n+ *\n+ * Under QEMU user-mode emulation, the host process may contain\n+ * internal threads (RCU, TCG workers) that are not guest threads.\n+ * These must be hidden from directory listings of /proc//task/\n+ * and signals to non-guest TIDs must return ESRCH.\n+ *\n+ * SPDX-License-Identifier: GPL-2.0-or-later\n+ */\n+#define _GNU_SOURCE\n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+\n+#define NUM_THREADS 3\n+\n+static pid_t guest_tids[NUM_THREADS + 1]; /* +1 for main thread */\n+static int num_guest_tids;\n+static pthread_barrier_t barrier;\n+\n+static pid_t gettid_sys(void)\n+{\n+ return syscall(SYS_gettid);\n+}\n+\n+static void *thread_func(void *arg)\n+{\n+ int idx = (int)(intptr_t)arg;\n+\n+ guest_tids[idx] = gettid_sys();\n+ pthread_barrier_wait(&barrier);\n+\n+ /* Wait for main thread to finish testing. */\n+ pthread_barrier_wait(&barrier);\n+ return NULL;\n+}\n+\n+/*\n+ * Read /proc/self/task/ and return the count of numeric entries\n+ * (thread TIDs). For each entry, verify it matches a known guest TID.\n+ */\n+static int count_and_verify_task_entries(void)\n+{\n+ DIR *dir;\n+ struct dirent *de;\n+ int count = 0;\n+\n+ dir = opendir(\"/proc/self/task\");\n+ assert(dir != NULL);\n+\n+ while ((de = readdir(dir)) != NULL) {\n+ char *endp;\n+ long tid;\n+ int i, found;\n+\n+ if (de->d_name[0] == '.') {\n+ continue; /* skip \".\" and \"..\" */\n+ }\n+\n+ tid = strtol(de->d_name, &endp, 10);\n+ if (*endp != '\\0' || tid <= 0) {\n+ continue; /* non-numeric entry */\n+ }\n+\n+ /* Every TID in the listing must be a known guest thread. */\n+ found = 0;\n+ for (i = 0; i < num_guest_tids; i++) {\n+ if (guest_tids[i] == (pid_t)tid) {\n+ found = 1;\n+ break;\n+ }\n+ }\n+ if (!found) {\n+ fprintf(stderr, \"FAIL: /proc/self/task/ contains unknown TID %ld\\n\",\n+ tid);\n+ fprintf(stderr, \" Known guest TIDs:\");\n+ for (i = 0; i < num_guest_tids; i++) {\n+ fprintf(stderr, \" %d\", guest_tids[i]);\n+ }\n+ fprintf(stderr, \"\\n\");\n+ }\n+ assert(found);\n+ count++;\n+ }\n+\n+ closedir(dir);\n+ return count;\n+}\n+\n+/*\n+ * Verify that tkill(tid, 0) succeeds for all guest TIDs and that\n+ * tkill/tgkill to a TID that should not exist returns ESRCH.\n+ */\n+static void test_tkill_validation(void)\n+{\n+ int i, ret;\n+ pid_t self = getpid();\n+\n+ /* Signal 0 to each guest TID should succeed via tkill and tgkill. */\n+ for (i = 0; i < num_guest_tids; i++) {\n+ ret = syscall(SYS_tkill, guest_tids[i], 0);\n+ if (ret != 0) {\n+ fprintf(stderr, \"FAIL: tkill(%d, 0) returned %d (errno=%d)\\n\",\n+ guest_tids[i], ret, errno);\n+ }\n+ assert(ret == 0);\n+\n+ ret = syscall(SYS_tgkill, self, guest_tids[i], 0);\n+ if (ret != 0) {\n+ fprintf(stderr,\n+ \"FAIL: tgkill(%d, %d, 0) returned %d (errno=%d)\\n\",\n+ self, guest_tids[i], ret, errno);\n+ }\n+ assert(ret == 0);\n+ }\n+\n+ /*\n+ * Try a TID that is very unlikely to be a guest thread. Use\n+ * pid_max (typically 4194304) minus 1 as a probe. On a real\n+ * kernel this returns ESRCH for a nonexistent thread; under QEMU\n+ * with validation it must also return ESRCH. In the (extremely\n+ * unlikely) case that the TID does exist on the host, the kernel\n+ * may return 0; tolerate that to avoid spurious failures.\n+ */\n+ ret = syscall(SYS_tkill, 4194303, 0);\n+ assert(ret == 0 || (ret == -1 && errno == ESRCH));\n+\n+ ret = syscall(SYS_tgkill, self, 4194303, 0);\n+ assert(ret == 0 || (ret == -1 && errno == ESRCH));\n+\n+ /* tgkill with a wrong tgid for a known-good tid must return ESRCH. */\n+ ret = syscall(SYS_tgkill, 4194303, guest_tids[0], 0);\n+ assert(ret == -1 && errno == ESRCH);\n+}\n+\n+int main(void)\n+{\n+ pthread_t threads[NUM_THREADS];\n+ int i, task_count;\n+\n+ pthread_barrier_init(&barrier, NULL, NUM_THREADS + 1);\n+\n+ /* Record main thread TID. */\n+ guest_tids[0] = gettid_sys();\n+ num_guest_tids = 1;\n+\n+ /* Spawn worker threads. */\n+ for (i = 0; i < NUM_THREADS; i++) {\n+ int ret = pthread_create(&threads[i], NULL, thread_func,\n+ (void *)(intptr_t)(i + 1));\n+ assert(ret == 0);\n+ }\n+\n+ /* Wait for all threads to record their TIDs. */\n+ pthread_barrier_wait(&barrier);\n+ num_guest_tids = NUM_THREADS + 1;\n+\n+ printf(\"Guest TIDs:\");\n+ for (i = 0; i < num_guest_tids; i++) {\n+ printf(\" %d\", guest_tids[i]);\n+ }\n+ printf(\"\\n\");\n+\n+ /* Test 1: /proc/self/task/ entry count matches guest thread count. */\n+ task_count = count_and_verify_task_entries();\n+ printf(\"/proc/self/task/ entries: %d, expected: %d\\n\",\n+ task_count, num_guest_tids);\n+ assert(task_count == num_guest_tids);\n+\n+ /* Test 2: tkill validation. */\n+ test_tkill_validation();\n+\n+ /* Release worker threads. */\n+ pthread_barrier_wait(&barrier);\n+\n+ for (i = 0; i < NUM_THREADS; i++) {\n+ pthread_join(threads[i], NULL);\n+ }\n+\n+ pthread_barrier_destroy(&barrier);\n+\n+ printf(\"PASS: /proc/self/task/ filtering and tkill validation\\n\");\n+ return EXIT_SUCCESS;\n+}\n","prefixes":["v2","3/3"]}