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authorLinus Torvalds <torvalds@linux-foundation.org>2025-10-02 18:44:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2025-10-02 18:44:54 -0700
commite406d57be7bd2a4e73ea512c1ae36a40a44e499e (patch)
tree83092b32f248f57dc10e8e789094a5894270f570 /tools/testing/selftests/proc/proc-net-dev-lseek.c
parent8804d970fab45726b3c7cd7f240b31122aa94219 (diff)
parent9f1c14c1de1bdde395f6cc893efa4f80a2ae3b2b (diff)
Merge tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mmHEADtorvalds/mastertorvalds/HEADmaster
Pull non-MM updates from Andrew Morton: - "ida: Remove the ida_simple_xxx() API" from Christophe Jaillet completes the removal of this legacy IDR API - "panic: introduce panic status function family" from Jinchao Wang provides a number of cleanups to the panic code and its various helpers, which were rather ad-hoc and scattered all over the place - "tools/delaytop: implement real-time keyboard interaction support" from Fan Yu adds a few nice user-facing usability changes to the delaytop monitoring tool - "efi: Fix EFI boot with kexec handover (KHO)" from Evangelos Petrongonas fixes a panic which was happening with the combination of EFI and KHO - "Squashfs: performance improvement and a sanity check" from Phillip Lougher teaches squashfs's lseek() about SEEK_DATA/SEEK_HOLE. A mere 150x speedup was measured for a well-chosen microbenchmark - plus another 50-odd singleton patches all over the place * tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (75 commits) Squashfs: reject negative file sizes in squashfs_read_inode() kallsyms: use kmalloc_array() instead of kmalloc() MAINTAINERS: update Sibi Sankar's email address Squashfs: add SEEK_DATA/SEEK_HOLE support Squashfs: add additional inode sanity checking lib/genalloc: fix device leak in of_gen_pool_get() panic: remove CONFIG_PANIC_ON_OOPS_VALUE ocfs2: fix double free in user_cluster_connect() checkpatch: suppress strscpy warnings for userspace tools cramfs: fix incorrect physical page address calculation kernel: prevent prctl(PR_SET_PDEATHSIG) from racing with parent process exit Squashfs: fix uninit-value in squashfs_get_parent kho: only fill kimage if KHO is finalized ocfs2: avoid extra calls to strlen() after ocfs2_sprintf_system_inode_name() kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths sched/task.h: fix the wrong comment on task_lock() nesting with tasklist_lock coccinelle: platform_no_drv_owner: handle also built-in drivers coccinelle: of_table: handle SPI device ID tables lib/decompress: use designated initializers for struct compress_format efi: support booting with kexec handover (KHO) ...
Diffstat (limited to 'tools/testing/selftests/proc/proc-net-dev-lseek.c')
-rw-r--r--tools/testing/selftests/proc/proc-net-dev-lseek.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/tools/testing/selftests/proc/proc-net-dev-lseek.c b/tools/testing/selftests/proc/proc-net-dev-lseek.c
new file mode 100644
index 000000000000..742a3e804451
--- /dev/null
+++ b/tools/testing/selftests/proc/proc-net-dev-lseek.c
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2025 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.
+ */
+#undef _GNU_SOURCE
+#define _GNU_SOURCE
+#undef NDEBUG
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <sched.h>
+/*
+ * Test that lseek("/proc/net/dev/", 0, SEEK_SET)
+ * a) works,
+ * b) does what you think it does.
+ */
+int main(void)
+{
+ /* /proc/net/dev output is deterministic in fresh netns only. */
+ if (unshare(CLONE_NEWNET) == -1) {
+ if (errno == ENOSYS || errno == EPERM) {
+ return 4;
+ }
+ return 1;
+ }
+
+ const int fd = open("/proc/net/dev", O_RDONLY);
+ assert(fd >= 0);
+
+ char buf1[4096];
+ const ssize_t rv1 = read(fd, buf1, sizeof(buf1));
+ /*
+ * Not "<=", this file can't be empty:
+ * there is header, "lo" interface with some zeroes.
+ */
+ assert(0 < rv1);
+ assert(rv1 <= sizeof(buf1));
+
+ /* Believe it or not, this line broke one day. */
+ assert(lseek(fd, 0, SEEK_SET) == 0);
+
+ char buf2[4096];
+ const ssize_t rv2 = read(fd, buf2, sizeof(buf2));
+ /* Not "<=", see above. */
+ assert(0 < rv2);
+ assert(rv2 <= sizeof(buf2));
+
+ /* Test that lseek rewinds to the beginning of the file. */
+ assert(rv1 == rv2);
+ assert(memcmp(buf1, buf2, rv1) == 0);
+
+ /* Contents of the file is not validated: this test is about lseek(). */
+
+ return 0;
+}