This test outputs lots of information. Let's conform the core part of
the test to TAP and leave the information printing messages for now.
Include ktap_helpers.sh to print conformed logs. Use KSFT_* macros to
return the correct exit code for the kselftest framework and CIs to
understand the exit status.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Let the compilers (clang) know that this function would just call
exit() and would never return. It is needed to avoid false positive
static analysis errors. All similar functions calling exit()
unconditionally have been marked as __noreturn.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

When logging an error from calling waitpid() on the child we print a
misleading error message saying that the error we report was returned by
the chilld. Fix this to say the error is from waitpid().

Applied after fixing merge conflict:
Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

When the child exits during the clone3() selftest we use WEXITSTATUS() to
get the exit status from the process without first checking WIFEXITED() to
see if the result will be valid. This can lead to incorrect results, for
example if the child exits due to signal. Add a WIFEXTED() check and report
any non-standard exit as a failure, using EXIT_FAILURE as the exit status
for call_clone3() since we otherwise report 0 or negative errnos.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Shuah reported a compiler warning with an Ubuntu GCC 13 build, I've been
unable to reproduce it but hopefully this fixes the issue:

clone3_set_tid.c:136:43: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘size_t’ {aka ‘long unsigned int’} [-Wformat=]
Reported-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

In order to facilitate debugging of issues from automated runs of the ftrace
selftests turn on verbose logging by default when run from the kselftest
runner. This is primarily used by automated systems where developers may
not have direct access to the system so defaulting to providing diagnostic
information which might help debug problems seems like a good idea.

When tests pass no extra output is generated, when they fail a full log of
the test run is provided. Since this really is rather verbose when there are
a large number of test failures or output is slow (eg, with a serial
console) this could substantially increase the run time for the tests which
might present problems with timeout detection for affected systems,
hopefully we keep the tests running well enough that this is not too much
of an issue.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

When -v is specified ftracetest will dump logs of test execution to the
console which if -K is also specified for KTAP output will result in
output that is not properly KTAP formatted. All that's required for KTAP
formatting is that anything we log have a '#' at the start of the line so
we can improve things by washing the output through a simple read loop.
This will help automated parsers when verbose mode is enabled.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Use ksft_exit_fail_perror() to print the value of errno and its string
form. This is the first user of the ksft_exit_fail_perror() and proves
the usefulness of this API.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Add a version of ksft_exit_fail_msg() which prints the errno and its
string form with ease. There is no benefit of exit message without
errno. Whenever some error occurs, instead of printing errno manually,
this function would be very helpful. In the next TAP ports or new tests,
this function will be used instead of ksft_exit_fail_msg() as it prints
errno.

Resolved merge conflict found in next between the following commits:
f7d5bcd3 ("selftests: kselftest: Mark functions that unconditionally call exit() as __noreturn")

f07041728422 ("selftests: add ksft_exit_fail_perror()")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

The comment on top of the file is used by many developers to glance over
all the available functions. Add the recently added ksft_perror() to it.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

The test results reported for the clone3_set_tid tests interact poorly with
automation for running kselftest since the reported test names include TIDs
dynamically allocated at runtime. A lot of automation for running kselftest
will compare runs by looking at the test name to identify if the same test
is being run so changing names make it look like the testsuite has been
updated to include new tests. This makes the results display less clearly
and breaks cases like bisection.

Address this by providing a brief description of the tests and logging that
along with the stable parameters for the test currently logged. The TIDs
are already logged separately in existing logging except for the final test
which has a new log message added. We also tweak the formatting of the
logging of expected/actual values for clarity.

There are still issues with the logging of skipped tests (many are simply
not logged at all when skipped and all are logged with different names) but
these are less disruptive since the skips are all based on not being run as
root, a condition likely to be stable for a given test system.
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Every test calls its cleanup function at the end of it's test function.
After the cleanup function pointer is added to the test framework this
can be simplified to executing the callback function at the end of the
generic test running function.

Make test cleanup functions static and call them from the end of
run_single_test() from the resctrl_test's cleanup function pointer.
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Ctrl-c handler isn't aware of what test is currently running. Because of
that it executes all cleanups even if they aren't necessary. Since the
ctrl-c handler uses the sa_sigaction system no parameters can be passed
to it as function arguments.

Add a global variable to make ctrl-c handler aware of the currently run
test and only execute the correct cleanup callback.
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Resctrl selftests use very similar functions to cleanup after
themselves. This creates a lot of code duplication. Also not being
hooked to the test framework means that ctrl-c handler isn't aware of
what test is currently running and executes all cleanups even though
only one is needed.

Add a function pointer to the resctrl_test struct and attach to it
cleanup functions from individual tests.
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Conform the layout, informational and status messages to TAP. No
functional change is intended other than the layout of output messages.
Improve the TAP messages as well.
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Conform the layout, informational and status messages to TAP. No
functional change is intended other than the layout of output messages.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Conform the layout, informational and status messages to TAP. No
functional change is intended other than the layout of output messages.
Add more logic code to skip the tests if particular configuration isn't
available to make sure that either we skip each test or mark it pass/fail.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

There are multiple #ifdef blocks inside functions where they return just
0 if #ifdef is false. This makes number of tests counting difficult.
Move those functions inside one #ifdef block and move all of them
together. This is preparatory patch for next patch to convert this into
TAP format. So in this patch, we are just moving functions around
without any changes.

With and without this patch, the output of this patch is same.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Currently the tty_tstamp_update test reports a different exit message
for every path it can exit via. This can be confusing for automated systems
as the string that gets logged is interpreted as a test name so if the test
status changes they can't tell that it's the same test case that was run,
they can see that the overall status of the test program is a failure but
it's not clear that it was running the same test.

Change all the messages that are logged to be diagnostic prints and log the
name of the program as the test name.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Currently there's no helper which a test can use to report it's result as
a KSFT_ result code, we can report a boolean pass/fail but not a skip. This
is sometimes a useful idiom so let's add a helper ksft_test_result_report()
which translates into the relevant report types.

Due to the use of va_args in the result reporting functions this is done as
a macro rather than an inline function as one might expect, none of the
alternatives looked particularly great.

Resolved merge conflict in next betwwen the following commits:
f7d5bcd3 ("selftests: kselftest: Mark functions that unconditionally call exit() as __noreturn")

5d3a9274f0d1 ("kselftest: Add mechanism for reporting a KSFT_ result code")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

epoll can call out to vfs_poll() with a file pointer that may race with
the last 'fput()'. That would make f_count go down to zero, and while
the ep->mtx locking means that the resulting file pointer tear-down will
be blocked until the poll returns, it means that f_count is already
dead, and any use of it won't actually get a reference to the file any
more: it's dead regardless.

Make sure we have a valid ref on the file pointer before we call down to
vfs_poll() from the epoll routines.

Link: https://lore.kernel.org/lkml/0000000000002d631f0615918f1e@google.com/
Reported-by: syzbot+045b454ab35fd82a35fb@syzkaller.appspotmail.com
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull EDAC fixes from Borislav Petkov:

 - Fix error logging and check user-supplied data when injecting an
   error in the versal EDAC driver

* tag 'edac_urgent_for_v6.9_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
  EDAC/versal: Do not log total error counts
  EDAC/versal: Check user-supplied data before injecting an error
  EDAC/versal: Do not register for NOC errors

Pull powerpc fixes from Michael Ellerman:

 - Fix incorrect delay handling in the plpks (keystore) code

 - Fix a panic when an LPAR boots with a frozen PE

Thanks to Andrew Donnellan, Gaurav Batra, Nageswara R Sastry, and Nayna
Jain.

* tag 'powerpc-6.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/pseries/iommu: LPAR panics during boot up with a frozen PE
  powerpc/pseries: make max polling consistent for longer H_CALLs

Pull misc x86 fixes from Ingo Molnar:

 - Remove the broken vsyscall emulation code from
   the page fault code

 - Fix kexec crash triggered by certain SEV RMP
   table layouts

 - Fix unchecked MSR access error when disabling
   the x2APIC via iommu=off

* tag 'x86-urgent-2024-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Remove broken vsyscall emulation code from the page fault code
  x86/apic: Don't access the APIC when disabling x2APIC
  x86/sev: Add callback to apply RMP table fixups for kexec
  x86/e820: Add a new e820 table update helper

Pull irq fix from Ingo Molnar:
 "Fix suspicious RCU usage in __do_softirq()"

* tag 'irq-urgent-2024-05-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  softirq: Fix suspicious RCU usage in __do_softirq()

Pull char/misc driver fixes from Greg KH:
 "Here are some small char/misc/other driver fixes and new device ids
  for 6.9-rc7 that resolve some reported problems.

  Included in here are:

   - iio driver fixes

   - mei driver fix and new device ids

   - dyndbg bugfix

   - pvpanic-pci driver bugfix

   - slimbus driver bugfix

   - fpga new device id

  All have been in linux-next with no reported problems"

* tag 'char-misc-6.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  slimbus: qcom-ngd-ctrl: Add timeout for wait operation
  dyndbg: fix old BUG_ON in >control parser
  misc/pvpanic-pci: register attributes via pci_driver
  fpga: dfl-pci: add PCI subdevice ID for Intel D5005 card
  mei: me: add lunar lake point M DID
  mei: pxp: match against PCI_CLASS_DISPLAY_OTHER
  iio:imu: adis16475: Fix sync mode setting
  iio: accel: mxc4005: Reset chip on probe() and resume()
  iio: accel: mxc4005: Interrupt handling fixes
  dt-bindings: iio: health: maxim,max30102: fix compatible check
  iio: pressure: Fixes SPI support for BMP3xx devices
  iio: pressure: Fixes BME280 SPI driver data

Pull USB driver fixes from Greg KH:
 "Here are some small USB driver fixes for reported problems for
  6.9-rc7. Included in here are:

   - usb core fixes for found issues

   - typec driver fixes for reported problems

   - usb gadget driver fixes for reported problems

   - xhci build fixes

   - dwc3 driver fixes for reported issues

  All of these have been in linux-next this past week with no reported
  problems"

* tag 'usb-6.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: typec: tcpm: Check for port partner validity before consuming it
  usb: typec: tcpm: enforce ready state when queueing alt mode vdm
  usb: typec: tcpm: unregister existing source caps before re-registration
  usb: typec: tcpm: clear pd_event queue in PORT_RESET
  usb: typec: tcpm: queue correct sop type in tcpm_queue_vdm_unlocked
  usb: Fix regression caused by invalid ep0 maxpacket in virtual SuperSpeed device
  usb: ohci: Prevent missed ohci interrupts
  usb: typec: qcom-pmic: fix pdphy start() error handling
  usb: typec: qcom-pmic: fix use-after-free on late probe errors
  usb: gadget: f_fs: Fix a race condition when processing setup packets.
  USB: core: Fix access violation during port device removal
  usb: dwc3: core: Prevent phy suspend during init
  usb: xhci-plat: Don't include xhci.h
  usb: gadget: uvc: use correct buffer size when parsing configfs lists
  usb: gadget: composite: fix OS descriptors w_value logic
  usb: gadget: f_fs: Fix race between aio_cancel() and AIO request complete

Pull input fixes from Dmitry Torokhov:

 - a new ID for ASUS ROG RAIKIRI controllers added to xpad driver

 - amimouse driver structure annotated with __refdata to prevent section
   mismatch warnings.

* tag 'input-for-v6.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: amimouse - mark driver struct with __refdata to prevent section mismatch
  Input: xpad - add support for ASUS ROG RAIKIRI

Merge tag 'probes-fixes-v6.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes fix from Masami Hiramatsu:

 - probe-events: Fix memory leak in parsing probe argument.

   There is a memory leak (forget to free an allocated buffer) in a
   memory allocation failure path. Fix it to jump to the correct error
   handling code.

* tag 'probes-fixes-v6.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/probes: Fix memory leak in traceprobe_parse_probe_arg_body()

Pull tracing and tracefs fixes from Steven Rostedt:

 - Fix RCU callback of freeing an eventfs_inode.

   The freeing of the eventfs_inode from the kref going to zero freed
   the contents of the eventfs_inode and then used kfree_rcu() to free
   the inode itself. But the contents should also be protected by RCU.
   Switch to a call_rcu() that calls a function to free all of the
   eventfs_inode after the RCU synchronization.

 - The tracing subsystem maps its own descriptor to a file represented
   by eventfs. The freeing of this descriptor needs to know when the
   last reference of an eventfs_inode is released, but currently there
   is no interface for that.

   Add a "release" callback to the eventfs_inode entry array that allows
   for freeing of data that can be referenced by the eventfs_inode being
   opened. Then increment the ref counter for this descriptor when the
   eventfs_inode file is created, and decrement/free it when the last
   reference to the eventfs_inode is released and the file is removed.
   This prevents races between freeing the descriptor and the opening of
   the eventfs file.

 - Fix the permission processing of eventfs.

   The change to make the permissions of eventfs default to the mount
   point but keep track of when changes were made had a side effect that
   could cause security concerns. When the tracefs is remounted with a
   given gid or uid, all the files within it should inherit that gid or
   uid. But if the admin had changed the permission of some file within
   the tracefs file system, it would not get updated by the remount.

   This caused the kselftest of file permissions to fail the second time
   it is run. The first time, all changes would look fine, but the
   second time, because the changes were "saved", the remount did not
   reset them.

   Create a link list of all existing tracefs inodes, and clear the
   saved flags on them on a remount if the remount changes the
   corresponding gid or uid fields.

   This also simplifies the code by removing the distinction between the
   toplevel eventfs and an instance eventfs. They should both act the
   same. They were different because of a misconception due to the
   remount not resetting the flags. Now that remount resets all the
   files and directories to default to the root node if a uid/gid is
   specified, it makes the logic simpler to implement.

* tag 'trace-v6.9-rc6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  eventfs: Have "events" directory get permissions from its parent
  eventfs: Do not treat events directory different than other directories
  eventfs: Do not differentiate the toplevel events directory
  tracefs: Still use mount point as default permissions for instances
  tracefs: Reset permissions on remount if permissions are options
  eventfs: Free all of the eventfs_inode after RCU
  eventfs/tracing: Add callback for release of an eventfs_inode

Pull dma-mapping fix from Christoph Hellwig:

 - fix the combination of restricted pools and dynamic swiotlb
   (Will Deacon)

* tag 'dma-mapping-6.9-2024-05-04' of git://git.infradead.org/users/hch/dma-mapping:
  swiotlb: initialise restricted pool list_head when SWIOTLB_DYNAMIC=y

Pull clk fixes from Stephen Boyd:
 "A handful of clk driver fixes:

   - Avoid a deadlock in the Qualcomm clk driver by making the regulator
     which supplies the GDSC optional

   - Restore RPM clks on Qualcomm msm8976 by setting num_clks

   - Fix Allwinner H6 CPU rate changing logic to avoid system crashes by
     temporarily reparenting the CPU clk to something that isn't being
     changed

   - Set a MIPI PLL min/max rate on Allwinner A64 to fix blank screens
     on some devices

   - Revert back to of_match_device() in the Samsung clkout driver to
     get the match data based on the parent device's compatible string"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: samsung: Revert "clk: Use device_get_match_data()"
  clk: sunxi-ng: a64: Set minimum and maximum rate for PLL-MIPI
  clk: sunxi-ng: common: Support minimum and maximum rate
  clk: sunxi-ng: h6: Reparent CPUX during PLL CPUX rate change
  clk: qcom: smd-rpm: Restore msm8976 num_clk
  clk: qcom: gdsc: treat optional supplies as optional

The events directory gets its permissions from the root inode. But this
can cause an inconsistency if the instances directory changes its
permissions, as the permissions of the created directories under it should
inherit the permissions of the instances directory when directories under
it are created.

Currently the behavior is:

 # cd /sys/kernel/tracing
 # chgrp 1002 instances
 # mkdir instances/foo
 # ls -l instances/foo
[..]
 -r--r-----  1 root lkp  0 May  1 18:55 buffer_total_size_kb
 -rw-r-----  1 root lkp  0 May  1 18:55 current_tracer
 -rw-r-----  1 root lkp  0 May  1 18:55 error_log
 drwxr-xr-x  1 root root 0 May  1 18:55 events
 --w-------  1 root lkp  0 May  1 18:55 free_buffer
 drwxr-x---  2 root lkp  0 May  1 18:55 options
 drwxr-x--- 10 root lkp  0 May  1 18:55 per_cpu
 -rw-r-----  1 root lkp  0 May  1 18:55 set_event

All the files and directories under "foo" has the "lkp" group except the
"events" directory. That's because its getting its default value from the
mount point instead of its parent.

Have the "events" directory make its default value based on its parent's
permissions. That now gives:

 # ls -l instances/foo
[..]
 -rw-r-----  1 root lkp 0 May  1 21:16 buffer_subbuf_size_kb
 -r--r-----  1 root lkp 0 May  1 21:16 buffer_total_size_kb
 -rw-r-----  1 root lkp 0 May  1 21:16 current_tracer
 -rw-r-----  1 root lkp 0 May  1 21:16 error_log
 drwxr-xr-x  1 root lkp 0 May  1 21:16 events
 --w-------  1 root lkp 0 May  1 21:16 free_buffer
 drwxr-x---  2 root lkp 0 May  1 21:16 options
 drwxr-x--- 10 root lkp 0 May  1 21:16 per_cpu
 -rw-r-----  1 root lkp 0 May  1 21:16 set_event

Link: https://lore.kernel.org/linux-trace-kernel/20240502200906.161887248@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Treat the events directory the same as other directories when it comes to
permissions. The events directory was considered different because it's
dentry is persistent, whereas the other directory dentries are created
when accessed. But the way tracefs now does its ownership by using the
root dentry's permissions as the default permissions, the events directory
can get out of sync when a remount is performed setting the group and user
permissions.

Remove the special case for the events directory on setting the
attributes. This allows the updates caused by remount to work properly as
well as simplifies the code.

Link: https://lore.kernel.org/linux-trace-kernel/20240502200906.002923579@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

The toplevel events directory is really no different than the events
directory of instances. Having the two be different caused
inconsistencies and made it harder to fix the permissions bugs.

Make all events directories act the same.

Link: https://lore.kernel.org/linux-trace-kernel/20240502200905.846448710@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

If the instances directory's permissions were never change, then have it
and its children use the mount point permissions as the default.

Currently, the permissions of instance directories are determined by the
instance directory's permissions itself. But if the tracefs file system is
remounted and changes the permissions, the instance directory and its
children should use the new permission.

But because both the instance directory and its children use the instance
directory's inode for permissions, it misses the update.

To demonstrate this:

  # cd /sys/kernel/tracing/
  # mkdir instances/foo
  # ls -ld instances/foo
 drwxr-x--- 5 root root 0 May  1 19:07 instances/foo
  # ls -ld instances
 drwxr-x--- 3 root root 0 May  1 18:57 instances
  # ls -ld current_tracer
 -rw-r----- 1 root root 0 May  1 18:57 current_tracer

  # mount -o remount,gid=1002 .
  # ls -ld instances
 drwxr-x--- 3 root root 0 May  1 18:57 instances
  # ls -ld instances/foo/
 drwxr-x--- 5 root root 0 May  1 19:07 instances/foo/
  # ls -ld current_tracer
 -rw-r----- 1 root lkp 0 May  1 18:57 current_tracer

Notice that changing the group id to that of "lkp" did not affect the
instances directory nor its children. It should have been:

  # ls -ld current_tracer
 -rw-r----- 1 root root 0 May  1 19:19 current_tracer
  # ls -ld instances/foo/
 drwxr-x--- 5 root root 0 May  1 19:25 instances/foo/
  # ls -ld instances
 drwxr-x--- 3 root root 0 May  1 19:19 instances

  # mount -o remount,gid=1002 .
  # ls -ld current_tracer
 -rw-r----- 1 root lkp 0 May  1 19:19 current_tracer
  # ls -ld instances
 drwxr-x--- 3 root lkp 0 May  1 19:19 instances
  # ls -ld instances/foo/
 drwxr-x--- 5 root lkp 0 May  1 19:25 instances/foo/

Where all files were updated by the remount gid update.

Link: https://lore.kernel.org/linux-trace-kernel/20240502200905.686838327@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

There's an inconsistency with the way permissions are handled in tracefs.
Because the permissions are generated when accessed, they default to the
root inode's permission if they were never set by the user. If the user
sets the permissions, then a flag is set and the permissions are saved via
the inode (for tracefs files) or an internal attribute field (for
eventfs).

But if a remount happens that specify the permissions, all the files that
were not changed by the user gets updated, but the ones that were are not.
If the user were to remount the file system with a given permission, then
all files and directories within that file system should be updated.

This can cause security issues if a file's permission was updated but the
admin forgot about it. They could incorrectly think that remounting with
permissions set would update all files, but miss some.

For example:

 # cd /sys/kernel/tracing
 # chgrp 1002 current_tracer
 # ls -l
[..]
 -rw-r-----  1 root root 0 May  1 21:25 buffer_size_kb
 -rw-r-----  1 root root 0 May  1 21:25 buffer_subbuf_size_kb
 -r--r-----  1 root root 0 May  1 21:25 buffer_total_size_kb
 -rw-r-----  1 root lkp  0 May  1 21:25 current_tracer
 -rw-r-----  1 root root 0 May  1 21:25 dynamic_events
 -r--r-----  1 root root 0 May  1 21:25 dyn_ftrace_total_info
 -r--r-----  1 root root 0 May  1 21:25 enabled_functions

Where current_tracer now has group "lkp".

 # mount -o remount,gid=1001 .
 # ls -l
 -rw-r-----  1 root tracing 0 May  1 21:25 buffer_size_kb
 -rw-r-----  1 root tracing 0 May  1 21:25 buffer_subbuf_size_kb
 -r--r-----  1 root tracing 0 May  1 21:25 buffer_total_size_kb
 -rw-r-----  1 root lkp     0 May  1 21:25 current_tracer
 -rw-r-----  1 root tracing 0 May  1 21:25 dynamic_events
 -r--r-----  1 root tracing 0 May  1 21:25 dyn_ftrace_total_info
 -r--r-----  1 root tracing 0 May  1 21:25 enabled_functions

Everything changed but the "current_tracer".

Add a new link list that keeps track of all the tracefs_inodes which has
the permission flags that tell if the file/dir should use the root inode's
permission or not. Then on remount, clear all the flags so that the
default behavior of using the root inode's permission is done for all
files and directories.

Link: https://lore.kernel.org/linux-trace-kernel/20240502200905.529542160@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 8186fff7 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

The freeing of eventfs_inode via a kfree_rcu() callback. But the content
of the eventfs_inode was being freed after the last kref. This is
dangerous, as changes are being made that can access the content of an
eventfs_inode from an RCU loop.

Instead of using kfree_rcu() use call_rcu() that calls a function to do
all the freeing of the eventfs_inode after a RCU grace period has expired.

Link: https://lore.kernel.org/linux-trace-kernel/20240502200905.370261163@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 43aa6f97 ("eventfs: Get rid of dentry pointers without refcounts")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Synthetic events create and destroy tracefs files when they are created
and removed. The tracing subsystem has its own file descriptor
representing the state of the events attached to the tracefs files.
There's a race between the eventfs files and this file descriptor of the
tracing system where the following can cause an issue:

With two scripts 'A' and 'B' doing:

  Script 'A':
    echo "hello int aaa" > /sys/kernel/tracing/synthetic_events
    while :
    do
      echo 0 > /sys/kernel/tracing/events/synthetic/hello/enable
    done

  Script 'B':
    echo > /sys/kernel/tracing/synthetic_events

Script 'A' creates a synthetic event "hello" and then just writes zero
into its enable file.

Script 'B' removes all synthetic events (including the newly created
"hello" event).

What happens is that the opening of the "enable" file has:

 {
	struct trace_event_file *file = inode->i_private;
	int ret;

	ret = tracing_check_open_get_tr(file->tr);
 [..]

But deleting the events frees the "file" descriptor, and a "use after
free" happens with the dereference at "file->tr".

The file descriptor does have a reference counter, but there needs to be a
way to decrement it from the eventfs when the eventfs_inode is removed
that represents this file descriptor.

Add an optional "release" callback to the eventfs_entry array structure,
that gets called when the eventfs file is about to be removed. This allows
for the creating on the eventfs file to increment the tracing file
descriptor ref counter. When the eventfs file is deleted, it can call the
release function that will call the put function for the tracing file
descriptor.

This will protect the tracing file from being freed while a eventfs file
that references it is being opened.

Link: https://lore.kernel.org/linux-trace-kernel/20240426073410.17154-1-Tze-nan.Wu@mediatek.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240502090315.448cba46@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 5790b1fb ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: Tze-nan wu <Tze-nan.Wu@mediatek.com>
Tested-by: Tze-nan Wu (吳澤南) <Tze-nan.Wu@mediatek.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>