Pull scheduler updates from Ingo Molnar:
"Debuggability:
- Change most occurances of BUG_ON() to WARN_ON_ONCE()
- Reorganize & fix TASK_ state comparisons, turn it into a bitmap
- Update/fix misc scheduler debugging facilities
Load-balancing & regular scheduling:
- Improve the behavior of the scheduler in presence of lot of
SCHED_IDLE tasks - in particular they should not impact other
scheduling classes.
- Optimize task load tracking, cleanups & fixes
- Clean up & simplify misc load-balancing code
Freezer:
- Rewrite the core freezer to behave better wrt thawing and be
simpler in general, by replacing PF_FROZEN with TASK_FROZEN &
fixing/adjusting all the fallout.
Deadline scheduler:
- Fix the DL capacity-aware code
- Factor out dl_task_is_earliest_deadline() &
replenish_dl_new_period()
- Relax/optimize locking in task_non_contending()
Cleanups:
- Factor out the update_current_exec_runtime() helper
- Various cleanups, simplifications"
* tag 'sched-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
sched: Fix more TASK_state comparisons
sched: Fix TASK_state comparisons
sched/fair: Move call to list_last_entry() in detach_tasks
sched/fair: Cleanup loop_max and loop_break
sched/fair: Make sure to try to detach at least one movable task
sched: Show PF_flag holes
freezer,sched: Rewrite core freezer logic
sched: Widen TAKS_state literals
sched/wait: Add wait_event_state()
sched/completion: Add wait_for_completion_state()
sched: Add TASK_ANY for wait_task_inactive()
sched: Change wait_task_inactive()s match_state
freezer,umh: Clean up freezer/initrd interaction
freezer: Have {,un}lock_system_sleep() save/restore flags
sched: Rename task_running() to task_on_cpu()
sched/fair: Cleanup for SIS_PROP
sched/fair: Default to false in test_idle_cores()
sched/fair: Remove useless check in select_idle_core()
sched/fair: Avoid double search on same cpu
sched/fair: Remove redundant check in select_idle_smt()
...
Rewrite the core freezer to behave better wrt thawing and be simpler
in general.
By replacing PF_FROZEN with TASK_FROZEN, a special block state, it is
ensured frozen tasks stay frozen until thawed and don't randomly wake
up early, as is currently possible.
As such, it does away with PF_FROZEN and PF_FREEZER_SKIP, freeing up
two PF_flags (yay!).
Specifically; the current scheme works a little like:
freezer_do_not_count();
schedule();
freezer_count();
And either the task is blocked, or it lands in try_to_freezer()
through freezer_count(). Now, when it is blocked, the freezer
considers it frozen and continues.
However, on thawing, once pm_freezing is cleared, freezer_count()
stops working, and any random/spurious wakeup will let a task run
before its time.
That is, thawing tries to thaw things in explicit order; kernel
threads and workqueues before doing bringing SMP back before userspace
etc.. However due to the above mentioned races it is entirely possible
for userspace tasks to thaw (by accident) before SMP is back.
This can be a fatal problem in asymmetric ISA architectures (eg ARMv9)
where the userspace task requires a special CPU to run.
As said; replace this with a special task state TASK_FROZEN and add
the following state transitions:
TASK_FREEZABLE -> TASK_FROZEN
__TASK_STOPPED -> TASK_FROZEN
__TASK_TRACED -> TASK_FROZEN
The new TASK_FREEZABLE can be set on any state part of TASK_NORMAL
(IOW. TASK_INTERRUPTIBLE and TASK_UNINTERRUPTIBLE) -- any such state
is already required to deal with spurious wakeups and the freezer
causes one such when thawing the task (since the original state is
lost).
The special __TASK_{STOPPED,TRACED} states *can* be restored since
their canonical state is in ->jobctl.
With this, frozen tasks need an explicit TASK_FROZEN wakeup and are
free of undue (early / spurious) wakeups.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220822114649.055452969@infradead.org
A transaction of type BINDER_TYPE_WEAK_HANDLE can fail to increment the
reference for a node. In this case, the target proc normally releases
the failed reference upon close as expected. However, if the target is
dying in parallel the call will race with binder_deferred_release(), so
the target could have released all of its references by now leaving the
cleanup of the new failed reference unhandled.
The transaction then ends and the target proc gets released making the
ref->proc now a dangling pointer. Later on, ref->node is closed and we
attempt to take spin_lock(&ref->proc->inner_lock), which leads to the
use-after-free bug reported below. Let's fix this by cleaning up the
failed reference on the spot instead of relying on the target to do so.
==================================================================
BUG: KASAN: use-after-free in _raw_spin_lock+0xa8/0x150
Write of size 4 at addr ffff5ca207094238 by task kworker/1:0/590
CPU: 1 PID: 590 Comm: kworker/1:0 Not tainted 5.19.0-rc8 #10
Hardware name: linux,dummy-virt (DT)
Workqueue: events binder_deferred_func
Call trace:
dump_backtrace.part.0+0x1d0/0x1e0
show_stack+0x18/0x70
dump_stack_lvl+0x68/0x84
print_report+0x2e4/0x61c
kasan_report+0xa4/0x110
kasan_check_range+0xfc/0x1a4
__kasan_check_write+0x3c/0x50
_raw_spin_lock+0xa8/0x150
binder_deferred_func+0x5e0/0x9b0
process_one_work+0x38c/0x5f0
worker_thread+0x9c/0x694
kthread+0x188/0x190
ret_from_fork+0x10/0x20
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Cc: stable <stable@kernel.org> # 4.14+
Link: https://lore.kernel.org/r/20220801182511.3371447-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The patchset in [1] exported some definitions to binder_internal.h in
order to make the debugfs entries such as 'stats' and 'transaction_log'
available in a binderfs instance. However, the DEFINE_SHOW_ATTRIBUTE
macro expands into a static function/variable pair, which in turn get
redefined each time a source file includes this internal header.
This problem was made evident after a report from the kernel test robot
<lkp@intel.com> where several W=1 build warnings are seen in downstream
kernels. See the following example:
include/../drivers/android/binder_internal.h:111:23: warning: 'binder_stats_fops' defined but not used [-Wunused-const-variable=]
111 | DEFINE_SHOW_ATTRIBUTE(binder_stats);
| ^~~~~~~~~~~~
include/linux/seq_file.h:174:37: note: in definition of macro 'DEFINE_SHOW_ATTRIBUTE'
174 | static const struct file_operations __name ## _fops = { \
| ^~~~~~
This patch fixes the above issues by moving back the definitions into
binder.c and instead creates an array of the debugfs entries which is
more convenient to share with binderfs and iterate through.
[1] https://lore.kernel.org/all/20190903161655.107408-1-hridya@google.com/
Fixes: 0e13e452da ("binder: Add stats, state and transactions files")
Fixes: 03e2e07e38 ("binder: Make transaction_log available in binderfs")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220701182041.2134313-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the target process is busy, incoming oneway transactions are
queued in the async_todo list. If the clients continue sending extra
oneway transactions while the target process is frozen, this queue can
become too large to accommodate new transactions. That's why binder
driver introduced ONEWAY_SPAM_DETECTION to detect this situation. It's
helpful to debug the async binder buffer exhausting issue, but the
issue itself isn't solved directly.
In real cases applications are designed to send oneway transactions
repeatedly, delivering updated inforamtion to the target process.
Typical examples are Wi-Fi signal strength and some real time sensor
data. Even if the apps might only care about the lastet information,
all outdated oneway transactions are still accumulated there until the
frozen process is thawed later. For this kind of situations, there's
no existing method to skip those outdated transactions and deliver the
latest one only.
This patch introduces a new transaction flag TF_UPDATE_TXN. To use it,
use apps can set this new flag along with TF_ONE_WAY. When such an
oneway transaction is to be queued into the async_todo list of a frozen
process, binder driver will check if any previous pending transactions
can be superseded by comparing their code, flags and target node. If
such an outdated pending transaction is found, the latest transaction
will supersede that outdated one. This effectively prevents the async
binder buffer running out and saves unnecessary binder read workloads.
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Li Li <dualli@google.com>
Link: https://lore.kernel.org/r/20220526220018.3334775-2-dualli@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull file descriptor fix from Al Viro:
"Fix for breakage in #work.fd this window"
* tag 'pull-work.fd-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix the breakage in close_fd_get_file() calling conventions change
It used to grab an extra reference to struct file rather than
just transferring to caller the one it had removed from descriptor
table. New variant doesn't, and callers need to be adjusted.
Reported-and-tested-by: syzbot+47dd250f527cb7bebf24@syzkaller.appspotmail.com
Fixes: 6319194ec5 ("Unify the primitives for file descriptor closing")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull file descriptor updates from Al Viro.
- Descriptor handling cleanups
* tag 'pull-18-rc1-work.fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
Unify the primitives for file descriptor closing
fs: remove fget_many and fput_many interface
io_uring_enter(): don't leave f.flags uninitialized
Commit 9474be34a7 ("binder: add failed transaction logging info")
dereferences target_{proc,thread} after they have been potentially
freed by binder_proc_dec_tmpref() and binder_thread_dec_tmpref().
This patch delays the release of the two references after their last
usage. Fixes the following two errors reported by smatch:
drivers/android/binder.c:3562 binder_transaction() error: dereferencing freed memory 'target_proc'
drivers/android/binder.c:3563 binder_transaction() error: dereferencing freed memory 'target_thread'
Fixes: 9474be34a7 ("binder: add failed transaction logging info")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220517185817.598872-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently we have 3 primitives for removing an opened file from descriptor
table - pick_file(), __close_fd_get_file() and close_fd_get_file(). Their
calling conventions are rather odd and there's a code duplication for no
good reason. They can be unified -
1) have __range_close() cap max_fd in the very beginning; that way
we don't need separate way for pick_file() to report being past the end
of descriptor table.
2) make {__,}close_fd_get_file() return file (or NULL) directly, rather
than returning it via struct file ** argument. Don't bother with
(bogus) return value - nobody wants that -ENOENT.
3) make pick_file() return NULL on unopened descriptor - the only caller
that used to care about the distinction between descriptor past the end
of descriptor table and finding NULL in descriptor table doesn't give
a damn after (1).
4) lift ->files_lock out of pick_file()
That actually simplifies the callers, as well as the primitives themselves.
Code duplication is also gone...
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Converting binder_debug() and binder_user_error() macros into functions
reduces the overall object size by 16936 bytes when cross-compiled with
aarch64-linux-gnu-gcc 11.2.0:
$ size drivers/android/binder.o.{old,new}
text data bss dec hex filename
77935 6168 20264 104367 197af drivers/android/binder.o.old
65551 1616 20264 87431 15587 drivers/android/binder.o.new
This is particularly beneficial to functions binder_transaction() and
binder_thread_write() which repeatedly use these macros and are both
part of the critical path for all binder transactions.
$ nm --size vmlinux.{old,new} |grep ' binder_transaction$'
0000000000002f60 t binder_transaction
0000000000002358 t binder_transaction
$ nm --size vmlinux.{old,new} |grep binder_thread_write
0000000000001c54 t binder_thread_write
00000000000014a8 t binder_thread_write
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220429235644.697372-5-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Provide a userspace mechanism to pull precise error information upon
failed operations. Extending the current error codes returned by the
interfaces allows userspace to better determine the course of action.
This could be for instance, retrying a failed transaction at a later
point and thus offloading the error handling from the driver.
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20220429235644.697372-3-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some android userspace is sending BINDER_TYPE_FDA objects with
num_fds=0. Like the previous patch, this is reproducible when
playing a video.
Before commit 09184ae9b5 BINDER_TYPE_FDA objects with num_fds=0
were 'correctly handled', as in no fixup was performed.
After commit 09184ae9b5 we aggregate fixup and skip regions in
binder_ptr_fixup structs and distinguish between the two by using
the skip_size field: if it's 0, then it's a fixup, otherwise skip.
When processing BINDER_TYPE_FDA objects with num_fds=0 we add a
skip region of skip_size=0, and this causes issues because now
binder_do_deferred_txn_copies will think this was a fixup region.
To address that, return early from binder_translate_fd_array to
avoid adding an empty skip region.
Fixes: 09184ae9b5 ("binder: defer copies of pre-patched txn data")
Acked-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Alessandro Astone <ales.astone@gmail.com>
Link: https://lore.kernel.org/r/20220415120015.52684-1-ales.astone@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When handling BINDER_TYPE_FDA object we are pushing a parent fixup
with a certain skip_size but no scatter-gather copy object, since
the copy is handled standalone.
If BINDER_TYPE_FDA is the last children the scatter-gather copy
loop will never stop to skip it, thus we are left with an item in
the parent fixup list. This will trigger the BUG_ON().
This is reproducible in android when playing a video.
We receive a transaction that looks like this:
obj[0] BINDER_TYPE_PTR, parent
obj[1] BINDER_TYPE_PTR, child
obj[2] BINDER_TYPE_PTR, child
obj[3] BINDER_TYPE_FDA, child
Fixes: 09184ae9b5 ("binder: defer copies of pre-patched txn data")
Acked-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Alessandro Astone <ales.astone@gmail.com>
Link: https://lore.kernel.org/r/20220415120015.52684-2-ales.astone@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the fixes in here as well, and also resolve some merge conflicts
in:
drivers/misc/eeprom/at25.c
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
wake_up_poll() uses nr_exclusive=1, so it's not guaranteed to wake up
all exclusive waiters. Yet, POLLFREE *must* wake up all waiters. epoll
and aio poll are fortunately not affected by this, but it's very
fragile. Thus, the new function wake_up_pollfree() has been introduced.
Convert binder to use wake_up_pollfree().
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: f5cb779ba1 ("ANDROID: binder: remove waitqueue when thread exits.")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20211209010455.42744-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
binder_uintptr_t is not the same as uintptr_t, so converting it into a
pointer requires a second cast:
drivers/android/binder.c: In function 'binder_translate_fd_array':
drivers/android/binder.c:2511:28: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
2511 | sender_ufda_base = (void __user *)sender_uparent->buffer + fda->parent_offset;
| ^
Fixes: 656e01f3ab ("binder: read pre-translated fds from sender buffer")
Acked-by: Todd Kjos <tkjos@google.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20211207122448.1185769-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
BINDER_TYPE_PTR objects point to memory areas in the
source process to be copied into the target buffer
as part of a transaction. This implements a scatter-
gather model where non-contiguous memory in a source
process is "gathered" into a contiguous region in
the target buffer.
The data can include pointers that must be fixed up
to correctly point to the copied data. To avoid making
source process pointers visible to the target process,
this patch defers the copy until the fixups are known
and then copies and fixeups are done together.
There is a special case of BINDER_TYPE_FDA which applies
the fixup later in the target process context. In this
case the user data is skipped (so no untranslated fds
become visible to the target).
Reviewed-by: Martijn Coenen <maco@android.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/20211130185152.437403-5-tkjos@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
