(from https://patchwork.kernel.org/patch/9817765/)
A race existed where one thread could register
a death notification for a node, while another
thread was cleaning up that node and sending
out death notifications for its references,
causing simultaneous access to ref->death
because different locks were held.
Test: boots, manual testing
Change-Id: Iff73312f34f70374f417beba4c4c82dd33cac119
Signed-off-by: Martijn Coenen <maco@google.com>
(from https://patchwork.kernel.org/patch/9817761/)
When printing transactions there were several race conditions
that could cause a stale pointer to be deferenced. Fixed by
reading the pointer once and using it if valid (which is
safe). The transaction buffer also needed protection via proc
lock, so it is only printed if we are holding the correct lock.
Bug: 36650912
Test: tested manually
Change-Id: I78240f99cc1a070d70a841c0d84d4306e2fd528d
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817771/)
Use proc->outer_lock to protect the binder_ref structure.
The outer lock allows functions operating on the binder_ref
to do nested acquires of node and inner locks as necessary
to attach refs to nodes atomically.
Binder refs must never be accesssed without holding the
outer lock.
Change-Id: Icf6add0eddf70473b39239960b2d9a524775b53a
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817763/)
Use the inner lock to protect thread accounting fields in
proc structure: max_threads, requested_threads,
requested_threads_started and ready_threads.
Change-Id: I5a17eb68812702f803d4e2806e7887de0b3af18e
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817779/)
This makes future changes to priority inheritance
easier, since we want to be able to look at a thread's
transaction stack when selecting a thread to inherit
priority for.
It also allows us to take just a single lock in a
few paths, where we used to take two in succession.
Change-Id: Idb1b6e9faa5c669978b2b3011fe326be8aece586
Signed-off-by: Martijn Coenen <maco@google.com>
(from https://patchwork.kernel.org/patch/9817775/)
proc->threads will need to be accessed with higher
locks of other processes held so use proc->inner_lock
to protect it. proc->tmp_ref now needs to be protected
by proc->inner_lock.
Change-Id: I176cfeca16bf7c9b34b428c16405f93db81d2ff8
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817783/)
When locks for binder_ref handling are added, proc->nodes
will need to be modified while holding the outer lock
Change-Id: I17b39e981c55130c14a62fe49900eceff6e3642b
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817769/)
node->node_lock is used to protect elements of node. No
need to acquire for fields that are invariant: debug_id,
ptr, cookie.
Change-Id: Ib7738e52fa7689767f17136e18cc05ff548b5717
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817769/)
The todo lists in the proc, thread, and node structures
are accessed by other procs/threads to place work
items on the queue.
The todo lists are protected by the new proc->inner_lock.
No locks should ever be nested under these locks. As the
name suggests, an outer lock will be introduced in
a later patch.
Change-Id: I7720bacf5ebae4af177e22fcab0900d54c94c11a
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817789/)
For correct behavior we need to hold the inner lock when
dequeuing and processing node work in binder_thread_read.
We now hold the inner lock when we enter the switch statement
and release it after processing anything that might be
affected by other threads.
We also need to hold the inner lock to protect the node
weak/strong ref tracking fields as long as node->proc
is non-NULL (if it is NULL then we are guaranteed that
we don't have any node work queued).
This means that other functions that manipulate these fields
must hold the inner lock. Refactored these functions to use
the inner lock.
Change-Id: I02c5cfdd3ab6dadea7f07f2a275faf3e27be77ad
Test: tested manually
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817791/)
There are 3 main spinlocks which must be acquired in this
order:
1) proc->outer_lock : protects most fields of binder_proc,
binder_thread, and binder_ref structures. binder_proc_lock()
and binder_proc_unlock() are used to acq/rel.
2) node->lock : protects most fields of binder_node.
binder_node_lock() and binder_node_unlock() are
used to acq/rel
3) proc->inner_lock : protects the thread and node lists
(proc->threads, proc->nodes) and all todo lists associated
with the binder_proc (proc->todo, thread->todo,
proc->delivered_death and node->async_todo).
binder_inner_proc_lock() and binder_inner_proc_unlock()
are used to acq/rel
Any lock under procA must never be nested under any lock at the same
level or below on procB.
Functions that require a lock held on entry indicate which lock
in the suffix of the function name:
foo_olocked() : requires node->outer_lock
foo_nlocked() : requires node->lock
foo_ilocked() : requires proc->inner_lock
foo_iolocked(): requires proc->outer_lock and proc->inner_lock
foo_nilocked(): requires node->lock and proc->inner_lock
Change-Id: Ied42674486092a0e3bdde64356e45b2494844558
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817795/)
When obtaining a node via binder_get_node(),
binder_get_node_from_ref() or binder_new_node(),
increment node->tmp_refs to take a
temporary reference on the node to ensure the node
persists while being used. binder_put_node() must
be called to remove the temporary reference.
Change-Id: I962b39d5cd80b2d7e4786bb87236ede7914e2db7
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817781/)
Once locks are added, binder_ref's will only be accessed
safely with the proc lock held. Refactor the inc/dec paths
to make them atomic with the binder_get_ref* paths and
node inc/dec. For example, instead of:
ref = binder_get_ref(proc, handle, strong);
...
binder_dec_ref(ref, strong);
we now have:
ret = binder_dec_ref_for_handle(proc, handle, strong, &rdata);
Since the actual ref is no longer exposed to callers, a
new struct binder_ref_data is introduced which can be used
to return a copy of ref state.
Change-Id: I7de22107f8ebc967cee63251d584fceb4ea56250
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817787/)
binder_thread and binder_proc may be accessed by other
threads when processing transaction. Therefore they
must be prevented from being freed while a transaction
is in progress that references them.
This is done by introducing a temporary reference
counter for threads and procs that indicates that the
object is in use and must not be freed. binder_thread_dec_tmpref()
and binder_proc_dec_tmpref() are used to decrement
the temporary reference.
It is safe to free a binder_thread if there
is no reference and it has been released
(indicated by thread->is_dead).
It is safe to free a binder_proc if it has no
remaining threads and no reference.
A spinlock is added to the binder_transaction
to safely access and set references for t->from
and for debug code to safely access t->to_thread
and t->to_proc.
Change-Id: I0a00a0294c3e93aea8b3f141c6f18e77ad244078
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817787/)
When initiating a transaction, the target_node must
have a strong ref on it. Then we take a second
strong ref to make sure the node survives until the
transaction is complete.
Change-Id: If7429cb43eda520ab89d45df6c19327cee97c60c
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817805/)
Since errors are tracked in the return_error/return_error2
fields of the binder_thread object and BR_TRANSACTION_COMPLETEs
can be tracked either in those fields or via the thread todo
work list, it is possible for errors to be reported ahead
of the associated txn complete.
Use the thread todo work list for errors to guarantee
order. Also changed binder_send_failed_reply to pop
the transaction even if it failed to send a reply.
Bug: 37218618
Test: tested manually
Change-Id: I196cfaeed09fdcd697f8ab25eea4e04241fdb08f
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://lkml.org/lkml/2017/6/29/754)
binder_pop_transaction needs to be split into 2 pieces to
to allow the proc lock to be held on entry to dequeue the
transaction stack, but no lock when kfree'ing the transaction.
Split into binder_pop_transaction_locked and binder_free_transaction
(the actual locks are still to be added).
Change-Id: I848ae994cc27b3cd083cff2dbd1071762784f4a3
Test: tested manually
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817807/)
The log->next index for the transaction log was
not protected when incremented. This led to a
case where log->next++ resulted in an index
larger than ARRAY_SIZE(log->entry) and eventually
a bad access to memory.
Fixed by making the log index an atomic64 and
converting to an array by using "% ARRAY_SIZE(log->entry)"
Also added "complete" field to the log entry which is
written last to tell the print code whether the
entry is complete
Bug: 62038227
Test: tested manually
Change-Id: I1bb1c1a332a6ac458a626f5bedd05022b56b91f2
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817815/)
Adds protection against malicious user code freeing
the same buffer at the same time which could cause
a crash. Cannot happen under normal use.
Bug: 36650912
Change-Id: I43e078cbf31c0789aaff5ceaf8f1a94c75f79d45
Test: tested manually
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817819/)
node is always non-NULL in binder_get_ref_for_node so the
conditional and else clause are not needed
Change-Id: I23f011ba59e1869d9577e6bf28e1f1dd38f45713
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817799/)
The looper member of struct binder_thread is a bitmask
of control bits. All of the existing bits are modified
by the affected thread except for BINDER_LOOPER_STATE_NEED_RETURN
which can be modified in binder_deferred_flush() by
another thread.
To avoid adding a spinlock around all read-mod-writes to
modify a bit, the BINDER_LOOPER_STATE_NEED_RETURN flag
is replaced by a separate field in struct binder_thread.
Bug: 33250092 32225111
Change-Id: Ia4cefbdbd683c6cb17c323ba7d278de5f2ca0745
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817813/)
Currently, the transaction complete work item is queued
after the transaction. This means that it is possible
for the transaction to be handled and a reply to be
enqueued in the current thread before the transaction
complete is enqueued, which violates the protocol
with userspace who may not expect the transaction
complete. Fixed by always enqueing the transaction
complete first.
Also, once the transaction is enqueued, it is unsafe
to access since it might be freed. Currently,
t->flags is accessed to determine whether a sync
wake is needed. Changed to access tr->flags
instead.
Change-Id: I6c01566e167a39cf17c9027c3817618182e56975
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817757/)
In binder_thread_read, the BINDER_WORK_NODE command is used
to communicate the references on the node to userspace. It
can take a couple of iterations in the loop to construct
the list of commands for user space. When locking is added,
the lock would need to be release on each iteration which
means the state could change. The work item is not dequeued
during this process which prevents a simpler queue management
that can just dequeue up front and handle the work item.
Fixed by changing the BINDER_WORK_NODE algorithm in
binder_thread_read to determine which commands to send
to userspace atomically in 1 pass so it stays consistent
with the kernel view.
The work item is now dequeued immediately since only
1 pass is needed.
Change-Id: I9b4109997b2d53ba661867b14d7336cd076be06d
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817751/)
Add additional information to determine the cause of binder
failures. Adds the following to failed transaction log and
kernel messages:
return_error : value returned for transaction
return_error_param : errno returned by binder allocator
return_error_line : line number where error detected
Also, return BR_DEAD_REPLY if an allocation error indicates
a dead proc (-ESRCH)
Bug: 36406078
Change-Id: Ifc8881fa5adfcced3f2d67f9030fbd3efa3e2cab
Test: tested manually
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817755/)
Use atomics for stats to avoid needing to lock for
increments/decrements
Bug: 33250092 32225111
Change-Id: I13e69b7f0485ccf16673e25091455781e1933a98
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817811/)
With the global lock, there was a mechanism to acceess
binder driver debugging information with the global
lock disabled to debug deadlocks or other issues.
This mechanism is rarely (if ever) used anymore
and wasn't needed during the development of
fine-grained locking in the binder driver.
Removing it.
Change-Id: Ie1cf45748cefa433607a97c2ef322e7906efe0f7
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817753/)
Move the binder allocator functionality to its own file
Continuation of splitting the binder allocator from the binder
driver. Split binder_alloc functions from normal binder functions.
Add kernel doc comments to functions declared extern in
binder_alloc.h
Change-Id: I8f1a967375359078b8e63c7b6b88a752c374a64a
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817753/)
Continuation of splitting the binder allocator from the binder
driver. Separate binder_alloc functions from normal binder
functions. Protect the allocator with a separate mutex.
Bug: 33250092 32225111
Change-Id: I634637415aa03c74145159d84f1749bbe785a8f3
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817817/)
The buffer's transaction has already been freed before
binder_deferred_release. No need to do it again.
Change-Id: I412709c23879c5e45a6c7304a588bba0a5223fc3
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817745/)
The binder allocator is logically separate from the rest
of the binder drivers. Separating the data structures
to prepare for splitting into separate file with separate
locking.
Change-Id: I5ca4df567ac4b8c8d6ee2116ae67c0c1d75c9747
Signed-off-by: Todd Kjos <tkjos@google.com>
(from https://patchwork.kernel.org/patch/9817747)
Use wake_up_interruptible_sync() to hint to the scheduler binder
transactions are synchronous wakeups. Disable preemption while waking
to avoid ping-ponging on the binder lock.
Change-Id: Ic406a232d0873662f80148e37acefe5243d912a0
Signed-off-by: Todd Kjos <tkjos@google.com>
Git-commit: 443c026e90820170aa3db2c21d2933ae5922f900
Git-repo: https://android.googlesource.com/kernel/msm
Signed-off-by: Omprakash Dhyade <odhyade@codeaurora.org>
This reverts commit 6a3b9c4984.
Sigh. Confusion reigns. The rest of the preempt_disable patch is not in common, so this shouldn't be here afterall (it is in several downstream branches that therefore need this one too).
Re-reverting. We don't want the preempt_disable stuff in common since fine-grained locking is coming soon.
Change-Id: I2595516cab28041fa72f4a38692266a0f2a01ab4
This change moves all global binder state into
the context struct, thereby completely separating
the state and the locks between two different contexts.
The debugfs entries remain global, printing entries
from all contexts.
Change-Id: If8e3e2bece7bc6f974b66fbcf1d91d529ffa62f0
Signed-off-by: Martijn Coenen <maco@google.com>
The binder allocator assumes that the thread that
called binder_open will never die for the lifetime of
that proc. That thread is normally the group_leader,
however it may not be. Use the group_leader instead
of current.
Bug: 35707103
Test: Created test case to open with temporary thread
Change-Id: Id693f74b3591f3524a8c6e9508e70f3e5a80c588
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Fix following warning on 32bit ARCH build:
CC drivers/android/binder.o
drivers/android/binder.c: In function ‘binder_transaction’:
./include/linux/kern_levels.h:4:18: warning: format ‘%lld’ expects argument of type ‘long long int’,
but argument 4 has type ‘binder_size_t {aka unsigned int}’ [-Wformat=]
drivers/android/binder.c:2047:3: note: in expansion of macro ‘binder_user_error’
binder_user_error("%d:%d got transaction with unaligned buffers size, %lld\n",
^
Change-Id: I943d0d4d54f7f2a019900cc18e55bed661bec5a5
Fixes: Change-Id: I02417f28cff14688f2e1d6fcb959438fd96566cc
(android: binder: support for scatter-gather.")
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
commit 0a3ffab93fe52530602fe47cd74802cffdb19c05 upstream.
Prevent using a binder_ref with only weak references where a strong
reference is required.
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch introduces a new binder_fd_array object,
that allows us to support one or more file descriptors
embedded in a buffer that is scatter-gathered.
Change-Id: I647a53cf0d905c7be0dfd9333806982def68dd74
Signed-off-by: Martijn Coenen <maco@google.com>
Previously all data passed over binder needed
to be serialized, with the exception of Binder
objects and file descriptors.
This patchs adds support for scatter-gathering raw
memory buffers into a binder transaction, avoiding
the need to first serialize them into a Parcel.
To remain backwards compatibile with existing
binder clients, it introduces two new command
ioctls for this purpose - BC_TRANSACTION_SG and
BC_REPLY_SG. These commands may only be used with
the new binder_transaction_data_sg structure,
which adds a field for the total size of the
buffers we are scatter-gathering.
Because memory buffers may contain pointers to
other buffers, we allow callers to specify
a parent buffer and an offset into it, to indicate
this is a location pointing to the buffer that
we are fixing up. The kernel will then take care
of fixing up the pointer to that buffer as well.
Change-Id: I02417f28cff14688f2e1d6fcb959438fd96566cc
Signed-off-by: Martijn Coenen <maco@google.com>
The binder_buffer allocator currently only allocates
space for the data and offsets buffers of a Parcel.
This change allows for requesting an additional chunk
of data in the buffer, which can for example be used
to hold additional meta-data about the transaction
(eg a security context).
Change-Id: I58ab9c383a2e1a3057aae6adaa596ce867f1b157
Signed-off-by: Martijn Coenen <maco@google.com>
Moved handling of fixup for binder objects,
handles and file descriptors into separate
functions.
Change-Id: If6849f1caee3834aa87d0ab08950bb1e21ec6e38
Signed-off-by: Martijn Coenen <maco@google.com>
Add a new module parameter 'devices', that can be
used to specify the names of the binder device
nodes we want to populate in /dev.
Each device node has its own context manager, and
is therefore logically separated from all the other
device nodes.
The config option CONFIG_ANDROID_BINDER_DEVICES can
be used to set the default value of the parameter.
This approach was favored over using IPC namespaces,
mostly because we require a single process to be a
part of multiple binder contexts, which seemed harder
to achieve with namespaces.
Change-Id: I3df72b2a19b5ad5a0360e6322482db7b00a12b24
Signed-off-by: Martijn Coenen <maco@google.com>
