diff options
| author | Sven Schnelle <svens@linux.ibm.com> | 2026-09-09 11:29:53 +0200 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-09-10 08:43:35 +0900 |
| commit | d22c3e0088e85be8131f7a9283f759cdbb20726d (patch) | |
| tree | 9668df2aa27b26f850d3ba5ba1287e443803675c /Documentation/filesystems/devpts.rst | |
| download | linux-stable-d22c3e0088e85be8131f7a9283f759cdbb20726d.tar.gz linux-stable-d22c3e0088e85be8131f7a9283f759cdbb20726d.zip | |
selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tcgrafted
The current regex also matches symbols in modules, which makes the
test fail on s390 where name_show is present only once in the kernel,
but also multiple times in modules:
000001b1401cdc20 t name_show
000001b0c05e6c40 t name_show [mdev]
000001b0c0495f30 t name_show [i2c_core]
Fix this by changing the regular expression to only match the function
name.
Link: https://lore.kernel.org/all/20260909092954.2200558-1-svens@linux.ibm.com/
Fixes: 03b80ff8023a ("selftests/ftrace: Add new test case which checks non unique symbol")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'Documentation/filesystems/devpts.rst')
| -rw-r--r-- | Documentation/filesystems/devpts.rst | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/Documentation/filesystems/devpts.rst b/Documentation/filesystems/devpts.rst new file mode 100644 index 000000000..b6324ab19 --- /dev/null +++ b/Documentation/filesystems/devpts.rst @@ -0,0 +1,36 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +The Devpts Filesystem +===================== + +Each mount of the devpts filesystem is now distinct such that ptys +and their indices allocated in one mount are independent from ptys +and their indices in all other mounts. + +All mounts of the devpts filesystem now create a ``/dev/pts/ptmx`` node +with permissions ``0000``. + +To retain backwards compatibility the a ptmx device node (aka any node +created with ``mknod name c 5 2``) when opened will look for an instance +of devpts under the name ``pts`` in the same directory as the ptmx device +node. + +As an option instead of placing a ``/dev/ptmx`` device node at ``/dev/ptmx`` +it is possible to place a symlink to ``/dev/pts/ptmx`` at ``/dev/ptmx`` or +to bind mount ``/dev/ptx/ptmx`` to ``/dev/ptmx``. If you opt for using +the devpts filesystem in this manner devpts should be mounted with +the ``ptmxmode=0666``, or ``chmod 0666 /dev/pts/ptmx`` should be called. + +Total count of pty pairs in all instances is limited by sysctls:: + + kernel.pty.max = 4096 - global limit + kernel.pty.reserve = 1024 - reserved for filesystems mounted from the initial mount namespace + kernel.pty.nr - current count of ptys + +Per-instance limit could be set by adding mount option ``max=<count>``. + +This feature was added in kernel 3.4 together with +``sysctl kernel.pty.reserve``. + +In kernels older than 3.4 sysctl ``kernel.pty.max`` works as per-instance limit. |
