From: Andrew Morton <akpm@linux-foundation.org>
To: adobriyan@gmail.com, akpm@linux-foundation.org,
christian.brauner@ubuntu.com, ebiederm@xmission.com,
fweimer@redhat.com, keescook@chromium.org, linux-mm@kvack.org,
mm-commits@vger.kernel.org, torvalds@linux-foundation.org
Subject: [patch 03/87] procfs: do not list TID 0 in /proc/<pid>/task
Date: Mon, 08 Nov 2021 18:31:30 -0800 [thread overview]
Message-ID: <20211109023130.QN61VzMwU%akpm@linux-foundation.org> (raw)
In-Reply-To: <20211108183057.809e428e841088b657a975ec@linux-foundation.org>
From: Florian Weimer <fweimer@redhat.com>
Subject: procfs: do not list TID 0 in /proc/<pid>/task
If a task exits concurrently, task_pid_nr_ns may return 0.
[akpm@linux-foundation.org: coding style tweaks]
[adobriyan@gmail.com: test that /proc/*/task doesn't contain "0"]
Link: https://lkml.kernel.org/r/YV88AnVzHxPafQ9o@localhost.localdomain
Link: https://lkml.kernel.org/r/8735pn5dx7.fsf@oldenburg.str.redhat.com
Signed-off-by: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
fs/proc/base.c | 3
tools/testing/selftests/proc/.gitignore | 1
tools/testing/selftests/proc/Makefile | 2
tools/testing/selftests/proc/proc-tid0.c | 81 +++++++++++++++++++++
4 files changed, 87 insertions(+)
--- a/fs/proc/base.c~procfs-do-not-list-tid-0-in-proc-pid-task
+++ a/fs/proc/base.c
@@ -3799,7 +3799,10 @@ static int proc_task_readdir(struct file
task = next_tid(task), ctx->pos++) {
char name[10 + 1];
unsigned int len;
+
tid = task_pid_nr_ns(task, ns);
+ if (!tid)
+ continue; /* The task has just exited. */
len = snprintf(name, sizeof(name), "%u", tid);
if (!proc_fill_cache(file, ctx, name, len,
proc_task_instantiate, task, NULL)) {
--- a/tools/testing/selftests/proc/.gitignore~procfs-do-not-list-tid-0-in-proc-pid-task
+++ a/tools/testing/selftests/proc/.gitignore
@@ -11,6 +11,7 @@
/proc-self-syscall
/proc-self-wchan
/proc-subset-pid
+/proc-tid0
/proc-uptime-001
/proc-uptime-002
/read
--- a/tools/testing/selftests/proc/Makefile~procfs-do-not-list-tid-0-in-proc-pid-task
+++ a/tools/testing/selftests/proc/Makefile
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0-only
CFLAGS += -Wall -O2 -Wno-unused-function
CFLAGS += -D_GNU_SOURCE
+LDFLAGS += -pthread
TEST_GEN_PROGS :=
TEST_GEN_PROGS += fd-001-lookup
@@ -13,6 +14,7 @@ TEST_GEN_PROGS += proc-self-map-files-00
TEST_GEN_PROGS += proc-self-syscall
TEST_GEN_PROGS += proc-self-wchan
TEST_GEN_PROGS += proc-subset-pid
+TEST_GEN_PROGS += proc-tid0
TEST_GEN_PROGS += proc-uptime-001
TEST_GEN_PROGS += proc-uptime-002
TEST_GEN_PROGS += read
--- /dev/null
+++ a/tools/testing/selftests/proc/proc-tid0.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2021 Alexey Dobriyan <adobriyan@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+// Test that /proc/*/task never contains "0".
+#include <sys/types.h>
+#include <dirent.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <pthread.h>
+
+static pid_t pid = -1;
+
+static void atexit_hook(void)
+{
+ if (pid > 0) {
+ kill(pid, SIGKILL);
+ }
+}
+
+static void *f(void *_)
+{
+ return NULL;
+}
+
+static void sigalrm(int _)
+{
+ exit(0);
+}
+
+int main(void)
+{
+ pid = fork();
+ if (pid == 0) {
+ /* child */
+ while (1) {
+ pthread_t pth;
+ pthread_create(&pth, NULL, f, NULL);
+ pthread_join(pth, NULL);
+ }
+ } else if (pid > 0) {
+ /* parent */
+ atexit(atexit_hook);
+
+ char buf[64];
+ snprintf(buf, sizeof(buf), "/proc/%u/task", pid);
+
+ signal(SIGALRM, sigalrm);
+ alarm(1);
+
+ while (1) {
+ DIR *d = opendir(buf);
+ struct dirent *de;
+ while ((de = readdir(d))) {
+ if (strcmp(de->d_name, "0") == 0) {
+ exit(1);
+ }
+ }
+ closedir(d);
+ }
+
+ return 0;
+ } else {
+ perror("fork");
+ return 1;
+ }
+}
_
next prev parent reply other threads:[~2021-11-09 2:31 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-09 2:30 incoming Andrew Morton
2021-11-09 2:31 ` [patch 01/87] vfs: keep inodes with page cache off the inode shrinker LRU Andrew Morton
2021-11-09 2:31 ` [patch 02/87] mm,hugetlb: remove mlock ulimit for SHM_HUGETLB Andrew Morton
2021-11-09 2:31 ` Andrew Morton [this message]
2021-11-09 2:31 ` [patch 04/87] x86/xen: update xen_oldmem_pfn_is_ram() documentation Andrew Morton
2021-11-09 2:31 ` [patch 05/87] x86/xen: simplify xen_oldmem_pfn_is_ram() Andrew Morton
2021-11-09 2:31 ` [patch 06/87] x86/xen: print a warning when HVMOP_get_mem_type fails Andrew Morton
2021-11-09 2:31 ` [patch 07/87] proc/vmcore: let pfn_is_ram() return a bool Andrew Morton
2021-11-09 2:31 ` [patch 08/87] proc/vmcore: convert oldmem_pfn_is_ram callback to more generic vmcore callbacks Andrew Morton
2021-11-09 3:59 ` Dave Young
2021-11-09 6:40 ` David Hildenbrand
2021-11-10 7:22 ` Baoquan He
2021-11-10 8:10 ` David Hildenbrand
2021-11-10 11:11 ` Dave Young
2021-11-10 11:21 ` David Hildenbrand
2021-11-10 11:28 ` Dave Young
2021-11-10 12:05 ` David Hildenbrand
2021-11-09 2:31 ` [patch 09/87] virtio-mem: factor out hotplug specifics from virtio_mem_init() into virtio_mem_init_hotplug() Andrew Morton
2021-11-09 2:31 ` [patch 10/87] virtio-mem: factor out hotplug specifics from virtio_mem_probe() " Andrew Morton
2021-11-09 2:31 ` [patch 11/87] virtio-mem: factor out hotplug specifics from virtio_mem_remove() into virtio_mem_deinit_hotplug() Andrew Morton
2021-11-09 2:32 ` [patch 12/87] virtio-mem: kdump mode to sanitize /proc/vmcore access Andrew Morton
2021-11-09 2:32 ` [patch 13/87] proc: allow pid_revalidate() during LOOKUP_RCU Andrew Morton
2021-11-09 2:32 ` [patch 14/87] kernel.h: drop unneeded <linux/kernel.h> inclusion from other headers Andrew Morton
2021-11-09 2:32 ` [patch 15/87] kernel.h: split out container_of() and typeof_member() macros Andrew Morton
2021-11-09 2:32 ` [patch 16/87] include/kunit/test.h: replace kernel.h with the necessary inclusions Andrew Morton
2021-11-09 2:32 ` [patch 17/87] include/linux/list.h: " Andrew Morton
2021-11-09 2:32 ` [patch 18/87] include/linux/llist.h: " Andrew Morton
2021-11-09 2:32 ` [patch 19/87] include/linux/plist.h: " Andrew Morton
2021-11-09 2:32 ` [patch 20/87] include/media/media-entity.h: " Andrew Morton
2021-11-09 2:32 ` [patch 21/87] include/linux/delay.h: " Andrew Morton
2021-11-09 2:32 ` [patch 22/87] include/linux/sbitmap.h: " Andrew Morton
2021-11-09 2:32 ` [patch 23/87] include/linux/radix-tree.h: " Andrew Morton
2021-11-09 2:32 ` [patch 24/87] include/linux/generic-radix-tree.h: " Andrew Morton
2021-11-09 2:32 ` [patch 25/87] kernel.h: split out instruction pointer accessors Andrew Morton
2021-11-09 2:32 ` [patch 26/87] linux/container_of.h: switch to static_assert Andrew Morton
2021-11-09 2:32 ` [patch 27/87] mailmap: update email address for Colin King Andrew Morton
2021-11-09 2:32 ` [patch 28/87] MAINTAINERS: add "exec & binfmt" section with myself and Eric Andrew Morton
2021-11-09 2:32 ` [patch 29/87] MAINTAINERS: rectify entry for ARM/TOSHIBA VISCONTI ARCHITECTURE Andrew Morton
2021-11-09 2:32 ` [patch 30/87] MAINTAINERS: rectify entry for HIKEY960 ONBOARD USB GPIO HUB DRIVER Andrew Morton
2021-11-09 2:33 ` [patch 31/87] MAINTAINERS: rectify entry for INTEL KEEM BAY DRM DRIVER Andrew Morton
2021-11-09 2:33 ` [patch 32/87] MAINTAINERS: rectify entry for ALLWINNER HARDWARE SPINLOCK SUPPORT Andrew Morton
2021-11-09 2:33 ` [patch 33/87] lib, stackdepot: check stackdepot handle before accessing slabs Andrew Morton
2021-11-09 2:33 ` [patch 34/87] lib, stackdepot: add helper to print stack entries Andrew Morton
2021-11-09 2:33 ` [patch 35/87] lib, stackdepot: add helper to print stack entries into buffer Andrew Morton
2021-11-09 2:33 ` [patch 36/87] include/linux/string_helpers.h: add linux/string.h for strlen() Andrew Morton
2021-11-09 2:33 ` [patch 37/87] lib: uninline simple_strntoull() as well Andrew Morton
2021-11-09 2:33 ` [patch 38/87] mm/scatterlist: replace the !preemptible warning in sg_miter_stop() Andrew Morton
2021-11-09 2:33 ` [patch 39/87] const_structs.checkpatch: add a few sound ops structs Andrew Morton
2021-11-09 2:33 ` [patch 40/87] checkpatch: improve EXPORT_SYMBOL test for EXPORT_SYMBOL_NS uses Andrew Morton
2021-11-09 2:33 ` [patch 41/87] checkpatch: get default codespell dictionary path from package location Andrew Morton
2021-11-09 2:33 ` [patch 42/87] binfmt_elf: reintroduce using MAP_FIXED_NOREPLACE Andrew Morton
2021-11-09 2:33 ` [patch 43/87] ELF: simplify STACK_ALLOC macro Andrew Morton
2021-11-09 2:33 ` [patch 44/87] kallsyms: remove arch specific text and data check Andrew Morton
2021-11-09 2:33 ` [patch 45/87] kallsyms: fix address-checks for kernel related range Andrew Morton
2021-11-09 2:33 ` [patch 46/87] sections: move and rename core_kernel_data() to is_kernel_core_data() Andrew Morton
2021-11-09 2:33 ` [patch 47/87] sections: move is_kernel_inittext() into sections.h Andrew Morton
2021-11-09 2:33 ` [patch 48/87] x86: mm: rename __is_kernel_text() to is_x86_32_kernel_text() Andrew Morton
2021-11-09 2:34 ` [patch 49/87] sections: provide internal __is_kernel() and __is_kernel_text() helper Andrew Morton
2021-11-09 2:34 ` [patch 50/87] mm: kasan: use is_kernel() helper Andrew Morton
2021-11-09 2:34 ` [patch 51/87] extable: use is_kernel_text() helper Andrew Morton
2021-11-09 2:34 ` [patch 52/87] powerpc/mm: use core_kernel_text() helper Andrew Morton
2021-11-09 2:34 ` [patch 53/87] microblaze: use is_kernel_text() helper Andrew Morton
2021-11-09 2:34 ` [patch 54/87] alpha: " Andrew Morton
2021-11-09 2:34 ` [patch 55/87] ramfs: fix mount source show for ramfs Andrew Morton
2021-11-09 2:34 ` [patch 56/87] init: make unknown command line param message clearer Andrew Morton
2021-11-09 2:34 ` [patch 57/87] coda: avoid NULL pointer dereference from a bad inode Andrew Morton
2021-11-09 2:34 ` [patch 58/87] coda: check for async upcall request using local state Andrew Morton
2021-11-09 2:34 ` [patch 59/87] coda: remove err which no one care Andrew Morton
2021-11-09 2:34 ` [patch 60/87] coda: avoid flagging NULL inodes Andrew Morton
2021-11-09 2:34 ` [patch 61/87] coda: avoid hidden code duplication in rename Andrew Morton
2021-11-09 2:34 ` [patch 62/87] coda: avoid doing bad things on inode type changes during revalidation Andrew Morton
2021-11-09 2:34 ` [patch 63/87] coda: convert from atomic_t to refcount_t on coda_vm_ops->refcnt Andrew Morton
2021-11-09 2:34 ` [patch 64/87] coda: use vmemdup_user to replace the open code Andrew Morton
2021-11-09 2:34 ` [patch 65/87] coda: bump module version to 7.2 Andrew Morton
2021-11-09 2:34 ` [patch 66/87] nilfs2: replace snprintf in show functions with sysfs_emit Andrew Morton
2021-11-09 2:35 ` [patch 67/87] nilfs2: remove filenames from file comments Andrew Morton
2021-11-09 2:35 ` [patch 68/87] hfs/hfsplus: use WARN_ON for sanity check Andrew Morton
2021-11-09 2:35 ` [patch 69/87] crash_dump: fix boolreturn.cocci warning Andrew Morton
2021-11-09 2:35 ` [patch 70/87] crash_dump: remove duplicate include in crash_dump.h Andrew Morton
2021-11-09 2:35 ` [patch 71/87] signal: remove duplicate include in signal.h Andrew Morton
2021-11-09 2:35 ` [patch 72/87] seq_file: move seq_escape() to a header Andrew Morton
2021-11-09 2:35 ` [patch 73/87] seq_file: fix passing wrong private data Andrew Morton
2021-11-09 2:35 ` [patch 74/87] kernel/fork.c: unshare(): use swap() to make code cleaner Andrew Morton
2021-11-09 2:35 ` [patch 75/87] sysv: use BUILD_BUG_ON instead of runtime check Andrew Morton
2021-11-09 2:35 ` [patch 76/87] Documentation/kcov: include types.h in the example Andrew Morton
2021-11-09 2:35 ` [patch 77/87] Documentation/kcov: define `ip' " Andrew Morton
2021-11-09 2:35 ` [patch 78/87] kcov: allocate per-CPU memory on the relevant node Andrew Morton
2021-11-09 2:35 ` [patch 79/87] kcov: avoid enable+disable interrupts if !in_task() Andrew Morton
2021-11-09 2:35 ` [patch 80/87] kcov: replace local_irq_save() with a local_lock_t Andrew Morton
2021-11-09 2:35 ` [patch 81/87] scripts/gdb: handle split debug for vmlinux Andrew Morton
2021-11-09 2:35 ` [patch 82/87] kernel/resource: clean up and optimize iomem_is_exclusive() Andrew Morton
2021-11-09 2:35 ` [patch 83/87] kernel/resource: disallow access to exclusive system RAM regions Andrew Morton
2021-11-09 2:35 ` [patch 84/87] virtio-mem: disallow mapping virtio-mem memory via /dev/mem Andrew Morton
2021-11-09 2:35 ` [patch 85/87] selftests/kselftest/runner/run_one(): allow running non-executable files Andrew Morton
2021-11-09 2:35 ` [patch 86/87] ipc: check checkpoint_restore_ns_capable() to modify C/R proc files Andrew Morton
2021-11-09 2:36 ` [patch 87/87] ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL Andrew Morton
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