Merge remote-tracking branch 'net/master'

Merge branch 'next' into for-linus

Prepare input updates for 5.12 merge window.

Merge tag 'v5.11' into next

Merge with mainline to get latest APIs and device tree bindings.

Merge tag 'amba-make-remove-return-void' of https://git.pengutronix.de/git/ukl/linux into devel-stable

Tag for adaptions to struct amba_driver::remove changing prototype

Merge branch 'cpuidle-fix' into fixes

Merge drm/drm-next into drm-intel-gt-next

Backmerging to get a common base for merging topic branches between
drm-intel-next and drm-intel-gt-next.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@l

Merge drm/drm-next into drm-intel-gt-next

Backmerging to get a common base for merging topic branches between
drm-intel-next and drm-intel-gt-next.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

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Merge drm/drm-next into drm-intel-next

sync-up to not fall too much behind.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Merge branch 'for-linus' into for-next

Back-merge of 5.11-devel branch for syncing the result changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Merge tag 'asoc-fix-v5.11-rc2' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.11

A collection of mostly driver specific fixes, plus a maintainers

Merge tag 'asoc-fix-v5.11-rc2' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.11

A collection of mostly driver specific fixes, plus a maintainership
update for TI and a fix for DAPM driver removal paths.

show more ...

Merge drm/drm-next into drm-misc-next

Staying in sync to drm-next, and to be able to pull ttm fixes.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

Merge tag 'v5.11-rc1' into spi-5.11

Linux 5.11-rc1

Merge tag 'v5.11-rc1' into regulator-5.11

Linux 5.11-rc1

Merge tag 'v5.11-rc1' into asoc-5.11

Linux 5.11-rc1

Merge remote-tracking branch 'torvalds/master' into perf/core

To pick up fixes and check what UAPI headers need to be synched.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull exec-update-lock update from Eric Biederman:
"The key point of this is to tra

Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull exec-update-lock update from Eric Biederman:
"The key point of this is to transform exec_update_mutex into a
rw_semaphore so readers can be separated from writers.

This makes it easier to understand what the holders of the lock are
doing, and makes it harder to contend or deadlock on the lock.

The real deadlock fix wound up in perf_event_open"

* 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
exec: Transform exec_update_mutex into a rw_semaphore

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Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull execve updates from Eric Biederman:
"This set of changes ultimately fixes the interaction

Merge branch 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull execve updates from Eric Biederman:
"This set of changes ultimately fixes the interaction of posix file
lock and exec. Fundamentally most of the change is just moving where
unshare_files is called during exec, and tweaking the users of
files_struct so that the count of files_struct is not unnecessarily
played with.

Along the way fcheck and related helpers were renamed to more
accurately reflect what they do.

There were also many other small changes that fell out, as this is the
first time in a long time much of this code has been touched.

Benchmarks haven't turned up any practical issues but Al Viro has
observed a possibility for a lot of pounding on task_lock. So I have
some changes in progress to convert put_files_struct to always rcu
free files_struct. That wasn't ready for the merge window so that will
have to wait until next time"

* 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
exec: Move io_uring_task_cancel after the point of no return
coredump: Document coredump code exclusively used by cell spufs
file: Remove get_files_struct
file: Rename __close_fd_get_file close_fd_get_file
file: Replace ksys_close with close_fd
file: Rename __close_fd to close_fd and remove the files parameter
file: Merge __alloc_fd into alloc_fd
file: In f_dupfd read RLIMIT_NOFILE once.
file: Merge __fd_install into fd_install
proc/fd: In fdinfo seq_show don't use get_files_struct
bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
file: Implement task_lookup_next_fd_rcu
kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
proc/fd: In tid_fd_mode use task_lookup_fd_rcu
file: Implement task_lookup_fd_rcu
file: Rename fcheck lookup_fd_rcu
file: Replace fcheck_files with files_lookup_fd_rcu
file: Factor files_lookup_fd_locked out of fcheck_files
file: Rename __fcheck_files to files_lookup_fd_raw
...

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exec: Transform exec_update_mutex into a rw_semaphore

Recently syzbot reported[0] that there is a deadlock amongst the users
of exec_update_mutex. The problematic lock ordering found by lockdep
was

exec: Transform exec_update_mutex into a rw_semaphore

Recently syzbot reported[0] that there is a deadlock amongst the users
of exec_update_mutex. The problematic lock ordering found by lockdep
was:

perf_event_open (exec_update_mutex -> ovl_i_mutex)
chown (ovl_i_mutex -> sb_writes)
sendfile (sb_writes -> p->lock)
by reading from a proc file and writing to overlayfs
proc_pid_syscall (p->lock -> exec_update_mutex)

While looking at possible solutions it occured to me that all of the
users and possible users involved only wanted to state of the given
process to remain the same. They are all readers. The only writer is
exec.

There is no reason for readers to block on each other. So fix
this deadlock by transforming exec_update_mutex into a rw_semaphore
named exec_update_lock that only exec takes for writing.

Cc: Jann Horn <jannh@google.com>
Cc: Vasiliy Kulikov <segoon@openwall.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christopher Yeoh <cyeoh@au1.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Fixes: eea9673250db ("exec: Add exec_update_mutex to replace cred_guard_mutex")
[0] https://lkml.kernel.org/r/00000000000063640c05ade8e3de@google.com
Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/87ft4mbqen.fsf@x220.int.ebiederm.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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exec: Move unshare_files and guarantee files_struct.count is correct

A while ago it was reported that posix file locking goes wrong when a
multi-threaded process calls exec. I looked into the histo

exec: Move unshare_files and guarantee files_struct.count is correct

A while ago it was reported that posix file locking goes wrong when a
multi-threaded process calls exec. I looked into the history and this
is definitely a regression, that should be fixed if we can.

This set of changes cleanups of the code in exec so hopefully this code
will not regress again. Then it adds helpers and fixes the users of
files_struct so the reference count is only incremented if COPY_FILES is
passed to clone (or if io_uring takes a reference). Then it removes
helpers (get_files_struct, __install_fd, __alloc_fd, __close_fd) that
are no longer needed and if used would encourage code that increments
the count of files_struct somewhere besides in clone when COPY_FILES is
passed.

In addition to fixing the bug in exec and simplifing the code this set
of changes by virtue of getting files_struct.count correct it optimizes
fdget. With proc and other places not temporarily increasing the count
on files_struct __fget_light should succeed more often in being able to
return a struct file without touching it's reference count.

Fixing the count in files_struct was suggested by Oleg[1].

For those that are interested in the history of this issue I have
included as much of it as I could find in the first change.

Since v1:

- Renamed the functions
__fcheck_files -> files_lookup_fd_raw
fcheck_files -> files_lookup_fd_locked
fcheck_files -> files_lookup_fd_rcu
fcheck_files -> lookup_fd_rcu
fcheck_task -> task_lookup_fd_rcu
fnext_task -> task_lookup_next_fd_rcu
__close_fd_get_file -> close_fd_get_file

- Simplified get_file_raw_ptr

- Removed ksys_close

- Examined the penalty for taking task_lock. The helper
task_lookup_next_fd_rcu takes task_lock each iteration. Concern was
expressed that this might be a problem. The function tid_fd_mode
isn called from tid_fd_revalidate which is called when ever a file
descriptor file is stat'ed, opened, or otherwise accessed. The
function tid_fd_mode histrocally called get_files_struct which took
and dropped task_lock. So the volume of task_lock calls is already
proportional to the number of file descriptors. A micro benchmark
did not see the move to task_lookup_next_fd_rcu making a difference
in performance. Which suggests that the change to taking the task
lock for every file descriptor found in task_lookup_next_fd will not
be a problem.

- Reviewed the code for conflicts with io_uring (especially the
removal of get_files_struct). To my surprise no conflicts were
found as io_uring does not use standard helpers but instead rolls
it's own version of get_files_struct by hand.

Documentation/filesystems/files.rst | 8 +-
arch/powerpc/platforms/cell/spufs/coredump.c | 2 +-
drivers/android/binder.c | 2 +-
fs/autofs/dev-ioctl.c | 5 +-
fs/coredump.c | 5 +-
fs/exec.c | 29 +++----
fs/file.c | 124 +++++++++++++--------------
fs/io_uring.c | 2 +-
fs/locks.c | 14 +--
fs/notify/dnotify/dnotify.c | 2 +-
fs/open.c | 2 +-
fs/proc/fd.c | 48 ++++-------
include/linux/fdtable.h | 40 +++++----
include/linux/syscalls.h | 12 ---
kernel/bpf/syscall.c | 20 +----
kernel/bpf/task_iter.c | 44 +++-------
kernel/fork.c | 12 +--
kernel/kcmp.c | 29 ++-----
18 files changed, 153 insertions(+), 247 deletions(-)

Eric W. Biederman (25):
exec: Don't open code get_close_on_exec
exec: Move unshare_files to fix posix file locking during exec
exec: Simplify unshare_files
exec: Remove reset_files_struct
kcmp: In kcmp_epoll_target use fget_task
bpf: In bpf_task_fd_query use fget_task
proc/fd: In proc_fd_link use fget_task
file: Rename __fcheck_files to files_lookup_fd_raw
file: Factor files_lookup_fd_locked out of fcheck_files
file: Replace fcheck_files with files_lookup_fd_rcu
file: Rename fcheck lookup_fd_rcu
file: Implement task_lookup_fd_rcu
proc/fd: In tid_fd_mode use task_lookup_fd_rcu
kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
file: Implement task_lookup_next_fd_rcu
proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
proc/fd: In fdinfo seq_show don't use get_files_struct
file: Merge __fd_install into fd_install
file: In f_dupfd read RLIMIT_NOFILE once.
file: Merge __alloc_fd into alloc_fd
file: Rename __close_fd to close_fd and remove the files parameter
file: Replace ksys_close with close_fd
file: Rename __close_fd_get_file close_fd_get_file
file: Remove get_files_struct

[1] https://lkml.kernel.org/r/20180915160423.GA31461@redhat.com
v1: https://lkml.kernel.org/r/87ft8l6ic3.fsf@x220.int.ebiederm.org
Reported-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Daniel P. Berrangé <berrange@redhat.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/87r1on1v62.fsf@x220.int.ebiederm.org
Link: https://lists.openvz.org/pipermail/criu/2020-November/045123.html
Link: https://marc.info/?l=openvz-criu&m=160591423214257
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

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kcmp: In get_file_raw_ptr use task_lookup_fd_rcu

Modify get_file_raw_ptr to use task_lookup_fd_rcu. The helper
task_lookup_fd_rcu does the work of taking the task lock and verifying
that task->file

kcmp: In get_file_raw_ptr use task_lookup_fd_rcu

Modify get_file_raw_ptr to use task_lookup_fd_rcu. The helper
task_lookup_fd_rcu does the work of taking the task lock and verifying
that task->files != NULL and then calls files_lookup_fd_rcu. So let
use the helper to make a simpler implementation of get_file_raw_ptr.

Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>
Link: https://lkml.kernel.org/r/20201120231441.29911-13-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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file: Replace fcheck_files with files_lookup_fd_rcu

This change renames fcheck_files to files_lookup_fd_rcu. All of the
remaining callers take the rcu_read_lock before calling this function
so the

file: Replace fcheck_files with files_lookup_fd_rcu

This change renames fcheck_files to files_lookup_fd_rcu. All of the
remaining callers take the rcu_read_lock before calling this function
so the _rcu suffix is appropriate. This change also tightens up the
debug check to verify that all callers hold the rcu_read_lock.

All callers that used to call files_check with the files->file_lock
held have now been changed to call files_lookup_fd_locked.

This change of name has helped remind me of which locks and which
guarantees are in place helping me to catch bugs later in the
patchset.

The need for better names became apparent in the last round of
discussion of this set of changes[1].

[1] https://lkml.kernel.org/r/CAHk-=wj8BQbgJFLa+J0e=iT-1qpmCRTbPAJ8gd6MJQ=kbRPqyQ@mail.gmail.com
Link: https://lkml.kernel.org/r/20201120231441.29911-9-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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kcmp: In kcmp_epoll_target use fget_task

Use the helper fget_task and simplify the code.

As well as simplifying the code this removes one unnecessary increment of
struct files_struct. This unneces

kcmp: In kcmp_epoll_target use fget_task

Use the helper fget_task and simplify the code.

As well as simplifying the code this removes one unnecessary increment of
struct files_struct. This unnecessary increment of files_struct.count can
result in exec unnecessarily unsharing files_struct and breaking posix
locks, and it can result in fget_light having to fallback to fget reducing
performance.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
v1: https://lkml.kernel.org/r/20200817220425.9389-4-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20201120231441.29911-4-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

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Merge branch 'master' into for-next

Sync with Linus' branch in order to be able to apply fixups
of more recent patches.

Merge branch 'next' into for-linus

Prepare input updates for 5.9 merge window.

Merge branch 'elan-i2c' into next

Bring in update to Elan touchpad driver to support newer touchpads with
higher resolution.

Merge branches 'for-5.7/upstream-fixes', 'for-5.8/apple', 'for-5.8/asus', 'for-5.8/core', 'for-5.8/intel-ish', 'for-5.8/logitech', 'for-5.8/mcp2221' and 'for-5.8/multitouch' into for-linus