Unify naming of return value to the preferred way.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Unify naming of return value to the preferred way.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

We recently tracked down a race condition that triggered a read for an
extent buffer with EXTENT_BUFFER_UPTODATE already set.  While this read
was in progress, other concurrent readers would see the UPTODATE bit and
return early as if the read was already complete, making accesses to the
extent buffer conflict with the read operation that was overwriting it.

Add a WARN_ON() to end_bbio_meta_read() for this situation to make
similar races easier to spot in the future.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

We are clearing the bit and waking up any waiters in two different
places.  Factor that code out into a static helper function.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

When unlocking a write lock on a drew lock, at btrfs_drew_write_unlock(),
it's pointless to wake up tasks waiting to acquire a read lock if we
didn't decrement the 'writers' counter down to 0, since a read lock can
only be acquired when the counter reaches a value of 0. Doing so is
harmless from a functional point of view, but it's not efficient due to
unnecessarily waking up tasks just for them to sleep again on the
waitqueue.

So change this to wake up readers only if we decremented the 'writers'
counter to 0.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

There's no point in having a static writepages callback in inode.c that
does nothing besides calling extent_writepages from extent_io.c.
So just remove the callback at inode.c and rename extent_writepages()
to btrfs_writepages().
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

There's no point in having a static readahead callback in inode.c that
does nothing besides calling extent_readahead() from extent_io.c.
So just remove the callback at inode.c and rename extent_readahead()
to btrfs_readahead().
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The __btrfs_tree_lock() and __btrfs_tree_read_lock() are using a naming
with a double underscore prefix, which is specially not proper for
exported functions. Remove the double underscore prefix from their name
and add the "_nested" suffix.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The functions btrfs_tree_lock() and btrfs_tree_read_lock() are very
trivial so that can be made inline and avoid call overhead, as they
are very often called inside critical sections (when searching a btree
for example, attempting to lock a child node/leaf while holding a lock
on the parent).

So make them static inline, which even reduces the size of the btrfs
module a little bit.

Before this change:

   $ size fs/btrfs/btrfs.ko
      text	   data	    bss	    dec	    hex	filename
   1718786	 156276	  16920	1891982	 1cde8e	fs/btrfs/btrfs.ko

After this change:

   $ size fs/btrfs/btrfs.ko
      text	   data	    bss	    dec	    hex	filename
   1718650	 156260	  16920	1891830	 1cddf6	fs/btrfs/btrfs.ko

Running fs_mark also showed a tiny improvement with this script:

   $ cat test.sh
   #!/bin/bash

   DEV=/dev/nullb0
   MNT=/mnt/nullb0
   FILES=100000
   THREADS=$(nproc --all)

   echo "performance" | \
       tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

   umount $DEV &> /dev/null
   mkfs.btrfs -f $DEV
   mount $DEV $MNT

   OPTS="-S 0 -L 5 -n $FILES -s 0 -t $THREADS -k"
   for ((i = 1; i <= $THREADS; i++)); do
        OPTS="$OPTS -d $MNT/d$i"
   done

   fs_mark $OPTS

   umount $MNT

Before this change:

   FSUse%        Count         Size    Files/sec     App Overhead
       10      1200000            0     180894.0         10705410
       16      2400000            0     228211.4         10765738
       23      3600000            0     215969.6         11011072
       30      4800000            0     199077.1         11145587
       46      6000000            0     176624.1         11658470

After this change:

   FSUse%        Count         Size    Files/sec     App Overhead
       10      1200000            0     185312.3         10708377
       16      2400000            0     229320.4         10858013
       23      3600000            0     217958.7         11006167
       30      4800000            0     205122.9         11112899
       46      6000000            0     178039.1         11438852
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

When creating a snapshot we first check with btrfs_lookup_dir_item() if
there is a name collision in the parent directory and then return an error
if there's a collision. Then later on when trying to insert a dir item for
the snapshot we BUG_ON() if the return value is -EEXIST or -EOVERFLOW:

  static noinline int create_pending_snapshot(...)
  {
     (...)

     /* check if there is a file/dir which has the same name. */
     dir_item = btrfs_lookup_dir_item(...);
     (...)

     ret = btrfs_insert_dir_item(...);
     /* We have check then name at the beginning, so it is impossible. */
     BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
     if (ret) {
        btrfs_abort_transaction(trans, ret);
        goto fail;
     }

     (...)
  }

It's impossible to get the -EEXIST because we previously checked for a
potential collision with btrfs_lookup_dir_item() and we know that after
that no one could have added a colliding name because at this point the
transaction is in its critical section, state TRANS_STATE_COMMIT_DOING,
so no one can join this transaction to add a colliding name and neither
can anyone start a new transaction to do that.

As for the -EOVERFLOW, that can't happen as long as we have the extended
references feature enabled, which is a mkfs default for many years now.

In either case, the BUG_ON() is excessive as we can properly deal with
any error and can abort the transaction and jump to the 'fail' label,
in which case we'll also get the useful stack trace (just like a BUG_ON())
from the abort if the error is either -EEXIST or -EOVERFLOW.

So remove the BUG_ON().
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Pull btrfs fixes from David Sterba:
 "Two more fixes, both have some visible effects on user space:

   - add check if quotas are enabled when passing qgroup inheritance
     info, this affects snapper that could fail to create a snapshot

   - do check for leaf/node flag WRITTEN earlier so that nodes are
     completely validated before access, this used to be done by
     integrity checker but it's been removed and left an unhandled case"

* tag 'for-6.9-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: make sure that WRITTEN is set on all metadata blocks
  btrfs: qgroup: do not check qgroup inherit if qgroup is disabled

This reverts commit 07ed11af.

Stephen Rostedt reports:
 "I went to run my tests on my VMs and the tests hung on boot up.
  Unfortunately, the most I ever got out was:

  [   93.607888] Testing event system initcall: OK
  [   93.667730] Running tests on all trace events:
  [   93.669757] Testing all events: OK
  [   95.631064] ------------[ cut here ]------------
  Timed out after 60 seconds"

and further debugging points to a possible circular locking dependency
between the console_owner locking and the worker pool locking.

Reverting the commit allows Steve's VM to boot to completion again.

[ This may obviously result in the "[TTM] Buffer eviction failed"
  messages again, which was the reason for that original revert. But at
  this point this seems preferable to a non-booting system... ]
Reported-and-bisected-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20240502081641.457aa25f@gandalf.local.home/Acked-by: Maxime Ripard <mripard@kernel.org>
Cc: Alex Constantino <dreaming.about.electric.sheep@gmail.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Timo Lindfors <timo.lindfors@iki.fi>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull slab fixes from Vlastimil Babka:

 - Fix for cleanup infrastructure (Dan Carpenter)

   This makes the __free(kfree) cleanup hooks not crash on error
   pointers.

 - SLUB fix for freepointer checking (Nicolas Bouchinet)

   This fixes a recently introduced bug that manifests when
   init_on_free, CONFIG_SLAB_FREELIST_HARDENED and consistency checks
   (slub_debug=F) are all enabled, and results in false-positive
   freepointer corrupt reports for caches that store freepointer outside
   of the object area.

* tag 'slab-for-6.9-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  mm/slab: make __free(kfree) accept error pointers
  mm/slub: avoid zeroing outside-object freepointer for single free

Merge tag 'auxdisplay-v6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/andy/linux-auxdisplay

Pull auxdisplay fixes from Andy Shevchenko:

 - A couple of non-critical build fixes to Character LCD library

 - Miscellaneous fixes here and there

* tag 'auxdisplay-v6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/andy/linux-auxdisplay:
  auxdisplay: charlcd: Don't rebuild when CONFIG_PANEL_BOOT_MESSAGE=y
  auxdisplay: charlcd: Add missing MODULE_DESCRIPTION()
  auxdisplay: seg-led-gpio: Convert to platform remove callback returning void
  auxdisplay: linedisp: Group display drivers together

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>

Pull cxl fix from Dave Jiang:
 "Add missing RCH support for endpoint access_coordinate calculation.

  A late bug was reported by Robert Richter that the Restricted CXL Host
  (RCH) support was missing in the CXL endpoint access_coordinate
  calculation.

  The missing support causes the topology iterator to stumble over a
  NULL pointer and triggers a kernel OOPS on a platform with CXL 1.1
  support.

  The fix bypasses RCH topology as the access_coordinate calculation is
  not necessary since RCH does not support hotplug and the memory region
  exported should be covered by the HMAT table already.

  A unit test is also added to cxl_test to check against future
  regressions on the topology iterator"

* tag 'cxl-fixes-6.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
  cxl: Fix cxl_endpoint_get_perf_coordinate() support for RCH

Pull xen fixes from Juergen Gross:
 "Two fixes when running as Xen PV guests for issues introduced in the
  6.9 merge window, both related to apic id handling"

* tag 'for-linus-6.9a-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen: return a sane initial apic id when running as PV guest
  x86/xen/smp_pv: Register the boot CPU APIC properly

Pull EFI fix from Ard Biesheuvel:
 "This works around a shortcoming in the memory acceptation API, which
  may apparently hog the CPU for long enough to trigger the softlockup
  watchdog.

  Note that this only affects confidential VMs running under the Intel
  TDX hypervisor, which is why I accepted this for now, but this should
  obviously be fixed properly in the future"

* tag 'efi-urgent-for-v6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi/unaccepted: touch soft lockup during memory accept

Pull block fixes from Jens Axboe:
 "Nothing major in here - an nvme pull request with mostly auth/tcp
  fixes, and a single fix for ublk not setting segment count and size
  limits"

* tag 'block-6.9-20240503' of git://git.kernel.dk/linux:
  nvme-tcp: strict pdu pacing to avoid send stalls on TLS
  nvmet: fix nvme status code when namespace is disabled
  nvmet-tcp: fix possible memory leak when tearing down a controller
  nvme: cancel pending I/O if nvme controller is in terminal state
  nvmet-auth: replace pr_debug() with pr_err() to report an error.
  nvmet-auth: return the error code to the nvmet_auth_host_hash() callers
  nvme: find numa distance only if controller has valid numa id
  ublk: remove segment count and size limits
  nvme: fix warn output about shared namespaces without CONFIG_NVME_MULTIPATH

Pull sound fixes from Takashi Iwai:
 "As usual in a late stage, we received a fair amount of fixes for ASoC,
  and it became bigger than wished. But all fixes are rather device-
  specific, and they look pretty safe to apply.

  A major par of changes are series of fixes for ASoC meson and SOF
  drivers as well as for Realtek and Cirrus codecs. In addition, recent
  emu10k1 regression fixes and usual HD-audio quirks are included"

* tag 'sound-6.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (46 commits)
  ALSA: hda/realtek: Fix build error without CONFIG_PM
  ALSA: hda/realtek: Fix conflicting PCI SSID 17aa:386f for Lenovo Legion models
  ALSA: hda/realtek - Set GPIO3 to default at S4 state for Thinkpad with ALC1318
  ALSA: hda: intel-sdw-acpi: fix usage of device_get_named_child_node()
  ALSA: hda: intel-dsp-config: harden I2C/I2S codec detection
  ASoC: cs35l56: fix usages of device_get_named_child_node()
  ASoC: da7219-aad: fix usage of device_get_named_child_node()
  ASoC: meson: cards: select SND_DYNAMIC_MINORS
  ASoC: meson: axg-tdm: add continuous clock support
  ASoC: meson: axg-tdm-interface: manage formatters in trigger
  ASoC: meson: axg-card: make links nonatomic
  ASoC: meson: axg-fifo: use threaded irq to check periods
  ALSA: hda/realtek: Fix mute led of HP Laptop 15-da3001TU
  ALSA: emu10k1: make E-MU FPGA writes potentially more reliable
  ALSA: emu10k1: fix E-MU dock initialization
  ALSA: emu10k1: use mutex for E-MU FPGA access locking
  ALSA: emu10k1: move the whole GPIO event handling to the workqueue
  ALSA: emu10k1: factor out snd_emu1010_load_dock_firmware()
  ALSA: emu10k1: fix E-MU card dock presence monitoring
  ASoC: rt715-sdca: volume step modification
  ...

Pull drm fixes from Dave Airlie:
 "Weekly fixes, mostly made up from amdgpu and some panel changes.

  Otherwise xe, nouveau, vmwgfx and a couple of others, all seems pretty
  on track.

  amdgpu:
   - Fix VRAM memory accounting
   - DCN 3.1 fixes
   - DCN 2.0 fix
   - DCN 3.1.5 fix
   - DCN 3.5 fix
   - DCN 3.2.1 fix
   - DP fixes
   - Seamless boot fix
   - Fix call order in amdgpu_ttm_move()
   - Fix doorbell regression
   - Disable panel replay temporarily

  amdkfd:
   - Flush wq before creating kfd process

  xe:
   - Fix UAF on rebind worker
   - Fix ADL-N display integration

  imagination:
   - fix page-count macro

  nouveau:
   - avoid page-table allocation failures
   - fix firmware memory allocation

  panel:
   - ili9341: avoid OF for device properties; respect deferred probe;
     fix usage of errno codes

  ttm:
   - fix status output

  vmwgfx:
   - fix legacy display unit
   - fix read length in fence signalling"

* tag 'drm-fixes-2024-05-03' of https://gitlab.freedesktop.org/drm/kernel: (25 commits)
  drm/xe/display: Fix ADL-N detection
  drm/panel: ili9341: Use predefined error codes
  drm/panel: ili9341: Respect deferred probe
  drm/panel: ili9341: Correct use of device property APIs
  drm/xe/vm: prevent UAF in rebind_work_func()
  drm/amd/display: Disable panel replay by default for now
  drm/amdgpu: fix doorbell regression
  drm/amdkfd: Flush the process wq before creating a kfd_process
  drm/amd/display: Disable seamless boot on 128b/132b encoding
  drm/amd/display: Fix DC mode screen flickering on DCN321
  drm/amd/display: Add VCO speed parameter for DCN31 FPU
  drm/amdgpu: once more fix the call oder in amdgpu_ttm_move() v2
  drm/amd/display: Allocate zero bw after bw alloc enable
  drm/amd/display: Fix incorrect DSC instance for MST
  drm/amd/display: Atom Integrated System Info v2_2 for DCN35
  drm/amd/display: Add dtbclk access to dcn315
  drm/amd/display: Ensure that dmcub support flag is set for DCN20
  drm/amd/display: Handle Y carry-over in VCP X.Y calculation
  drm/amdgpu: Fix VRAM memory accounting
  drm/vmwgfx: Fix invalid reads in fence signaled events
  ...