[Deepin-Kernel-SIG] [linux 6.6-y] [Upstream] Backport NTSYNC misc driver into v6.6#845
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[ Upstream commit 25b9cad ] ntsync uses a misc device as the simplest and least intrusive uAPI interface. Each file description on the device represents an isolated NT instance, intended to correspond to a single NT virtual machine. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20240329000621.148791-2-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.9-rc3 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit b46271e ] This corresponds to the NT syscall NtCreateSemaphore(). Semaphores are one of three types of object to be implemented in this driver, the others being mutexes and events. An NT semaphore contains a 32-bit counter, and is signaled and can be acquired when the counter is nonzero. The counter has a maximum value which is specified at creation time. The initial value of the semaphore is also specified at creation time. There are no restrictions on the maximum and initial value. Each object is exposed as an file, to which any number of fds may be opened. When all fds are closed, the object is deleted. Objects hold a pointer to the ntsync_device that created them. The device's reference count is driven by struct file. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20240329000621.148791-3-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.9-rc3 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit dc806bd ] This corresponds to the NT syscall NtReleaseSemaphore(). This increases the semaphore's internal counter by the given value, and returns the previous value. If the counter would overflow the defined maximum, the function instead fails and returns -EOVERFLOW. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20240329000621.148791-4-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.9-rc3 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit f5b335d ] The ntsync code is only partially enabled in the kernel at this point in time, creating the device node and that's about it. Don't confuse systems that expect to see a working ntsync interface by teasing it with this basic structure at this point in time, so mark the code as "broken" so that it is not built and enabled just yet. Once the rest of the code is accepted, this will be reverted so that the driver can be correctly built and used, but for now, this is the safest way forward. Reviewed-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/2024051450-abrasion-swizzle-550b@gregkh Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.10 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewer's GuideBackport the NTSYNC misc driver into Linux v6.6 by integrating the kernel implementation, UAPI, documentation, build targets, and comprehensive selftests. Sequence Diagram for NTSYNC Semaphore CreationsequenceDiagram
actor UserSpace
participant KernelDriver as "ntsync.c"
UserSpace->>KernelDriver: ioctl(fd_dev, NTSYNC_IOC_CREATE_SEM, &sem_args)
activate KernelDriver
KernelDriver->>KernelDriver: ntsync_alloc_obj(dev, NTSYNC_TYPE_SEM)
note right of KernelDriver: sem_args: initial count, max count
KernelDriver->>KernelDriver: Initialize ntsync_obj (type=SEM, count, max)
KernelDriver->>KernelDriver: ntsync_obj_get_fd(new_sem_obj)
KernelDriver-->>UserSpace: Return new_fd (for semaphore object)
deactivate KernelDriver
Sequence Diagram for NTSYNC Semaphore Release and WakesequenceDiagram
actor UserSpace
participant KernelDriver as "ntsync.c"
participant SemaphoreObject as "ntsync_obj (Semaphore)"
UserSpace->>KernelDriver: ioctl(fd_sem, NTSYNC_IOC_SEM_RELEASE, &release_count)
activate KernelDriver
KernelDriver->>SemaphoreObject: ntsync_lock_obj(sem)
activate SemaphoreObject
KernelDriver->>SemaphoreObject: prev_count = sem.u.sem.count
KernelDriver->>SemaphoreObject: sem.u.sem.count += release_count
opt sem.u.sem.count > sem.u.sem.max
SemaphoreObject-->>KernelDriver: Error (EOVERFLOW)
end
KernelDriver->>SemaphoreObject: try_wake_any_sem()
note right of SemaphoreObject: Wakes a task if sem.count > 0 and waiters exist
opt Has all_waiters (all_hint > 0)
KernelDriver->>SemaphoreObject: try_wake_all_obj()
end
SemaphoreObject-->>KernelDriver: ntsync_unlock_obj(sem)
deactivate SemaphoreObject
KernelDriver-->>UserSpace: Return (prev_count or error)
deactivate KernelDriver
Class Diagram for NTSYNC UAPI StructuresclassDiagram
direction LR
class ntsync_sem_args {
+__u32 count
+__u32 max
}
class ntsync_mutex_args {
+__u32 owner
+__u32 count
}
class ntsync_event_args {
+__u32 manual
+__u32 signaled
}
class ntsync_wait_args {
+__u64 timeout
+__u64 objs
+__u32 count
+__u32 index
+__u32 flags
+__u32 owner
+__u32 alert
+__u32 pad
}
Class Diagram for NTSYNC Kernel Driver StructuresclassDiagram
direction LR
class ntsync_obj {
+spinlock_t lock
+int dev_locked
+ntsync_type type
+file* file_ptr "struct file* file"
+ntsync_device* dev
+-- Semaphore Data (if type is SEM) --
+__u32 sem_count
+__u32 sem_max
+-- Mutex Data (if type is MUTEX) --
+__u32 mutex_count
+pid_t mutex_owner
+bool mutex_ownerdead
+-- Event Data (if type is EVENT) --
+bool event_manual
+bool event_signaled
+list_head any_waiters
+list_head all_waiters
+atomic_t all_hint
}
class ntsync_q_entry {
+list_head node
+ntsync_q* q
+ntsync_obj* obj
+__u32 index
}
class ntsync_q {
+task_struct* task
+__u32 owner
+atomic_t signaled
+bool all
+bool ownerdead
+__u32 count
+ntsync_q_entry entries[]
}
class ntsync_device {
+mutex wait_all_lock
+file* file_ptr "struct file* file"
}
ntsync_obj "*" -- "1" ntsync_device : associated_with
ntsync_q "1" -- "*" ntsync_q_entry : contains
ntsync_q_entry "1" -- "1" ntsync_q : part_of_queue
ntsync_q_entry "1" -- "1" ntsync_obj : references_object
File-Level Changes
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Pull Request Overview
This PR backports the NTSYNC misc driver into the v6.6 kernel while also removing the now‐redundant .llseek entries from multiple file_operations structures. The key changes include:
- Removal of .llseek = no_llseek from various driver file_operations.
- Updates to the Maintainers file to include the new NTSYNC driver.
- Addition of documentation for the ntsync userspace API.
Reviewed Changes
Copilot reviewed 227 out of 227 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| drivers/block/mtip32xx/mtip32xx.c | Removed redundant .llseek assignment |
| drivers/auxdisplay/charlcd.c | Removed redundant .llseek assignment |
| drivers/acpi/apei/erst-dbg.c | Removed redundant .llseek assignment |
| arch/x86/kernel/cpu/resctrl/pseudo_lock.c | Removed redundant .llseek assignment |
| arch/x86/kernel/cpu/mce/dev-mcelog.c | Removed redundant .llseek assignment |
| arch/um/drivers/hostaudio_kern.c | Removed redundant .llseek assignments |
| arch/um/drivers/harddog_kern.c | Removed redundant .llseek assignment |
| arch/s390/pci/pci_clp.c | Removed redundant .llseek assignment |
| arch/s390/kernel/sysinfo.c | Removed redundant .llseek assignment |
| arch/s390/kernel/perf_cpum_cf.c | Removed redundant .llseek assignment |
| arch/s390/kernel/debug.c | Removed redundant .llseek assignment |
| arch/s390/hypfs/inode.c | Removed redundant .llseek assignment |
| arch/s390/hypfs/hypfs_dbfs.c | Removed redundant .llseek assignment |
| arch/powerpc/platforms/cell/spufs/file.c | Removed redundant .llseek assignments (multiple spots) |
| arch/parisc/kernel/perf.c | Removed redundant .llseek assignment |
| MAINTAINERS | Added entry for NTSYNC driver |
| Documentation/watchdog/convert_drivers_to_kernel_api.rst | Removed outdated .llseek usage in example |
| Documentation/userspace-api/ntsync.rst | Added comprehensive documentation for ntsync API |
| Documentation/userspace-api/ioctl/ioctl-number.rst | Updated ioctl numbering for ntsync |
| Documentation/userspace-api/index.rst | Added ntsync to the userspace API index |
added 18 commits
June 4, 2025 00:02
[ Upstream commit d75abf2 ] Simplify the user API a bit by returning the fd as return value from the ioctl instead of through the argument pointer. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-2-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 5ec43d6 ] Use the more common "release" terminology, which is also the term used by NT, instead of "post" (which is used by POSIX). Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-3-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit b4a7b5f ] This corresponds to part of the functionality of the NT syscall NtWaitForMultipleObjects(). Specifically, it implements the behaviour where the third argument (wait_any) is TRUE, and it does not handle alertable waits. Those features have been split out into separate patches to ease review. This patch therefore implements the wait/wake infrastructure which comprises the core of ntsync's functionality. NTSYNC_IOC_WAIT_ANY is a vectored wait function similar to poll(). Unlike poll(), it "consumes" objects when they are signaled. For semaphores, this means decreasing one from the internal counter. At most one object can be consumed by this function. This wait/wake model is fundamentally different from that used anywhere else in the kernel, and for that reason ntsync does not use any existing infrastructure, such as futexes, kernel mutexes or semaphores, or wait_event(). Up to 64 objects can be waited on at once. As soon as one is signaled, the object with the lowest index is consumed, and that index is returned via the "index" field. A timeout is supported. The timeout is passed as a u64 nanosecond value, which represents absolute time measured against either the MONOTONIC or REALTIME clock (controlled by the flags argument). If U64_MAX is passed, the ioctl waits indefinitely. This ioctl validates that all objects belong to the relevant device. This is not necessary for any technical reason related to NTSYNC_IOC_WAIT_ANY, but will be necessary for NTSYNC_IOC_WAIT_ALL introduced in the following patch. Some padding fields are added for alignment and for fields which will be added in future patches (split out to ease review). Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-4-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit cdbb997 ] This is similar to NTSYNC_IOC_WAIT_ANY, but waits until all of the objects are simultaneously signaled, and then acquires all of them as a single atomic operation. Because acquisition of multiple objects is atomic, some complex locking is required. We cannot simply spin-lock multiple objects simultaneously, as that may disable preëmption for a problematically long time. Instead, modifying any object which may be involved in a wait-all operation takes a device-wide sleeping mutex, "wait_all_lock", instead of the normal object spinlock. Because wait-for-all is a rare operation, in order to optimize wait-for-any, this lock is only taken when necessary. "all_hint" is used to mark objects which are involved in a wait-for-all operation, and if an object is not, only its spinlock is taken. The locking scheme used here was written by Peter Zijlstra. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-5-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 5bc2479 ] This corresponds to the NT syscall NtCreateMutant(). An NT mutex is recursive, with a 32-bit recursion counter. When acquired via NtWaitForMultipleObjects(), the recursion counter is incremented by one. The OS records the thread which acquired it. The OS records the thread which acquired it. However, in order to keep this driver self-contained, the owning thread ID is managed by user-space, and passed as a parameter to all relevant ioctls. The initial owner and recursion count, if any, are specified when the mutex is created. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-6-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 31ca7bb ] This corresponds to the NT syscall NtReleaseMutant(). This syscall decrements the mutex's recursion count by one, and returns the previous value. If the mutex is not owned by the current task, the function instead fails and returns -EPERM. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-7-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit ecc2ee3 ] This does not correspond to any NT syscall. Rather, when a thread dies, it should be called by the NT emulator for each mutex, with the TID of the dying thread. NT mutexes are robust (in the pthread sense). When an NT thread dies, any mutexes it owned are immediately released. Acquisition of those mutexes by other threads will return a special value indicating that the mutex was abandoned, like EOWNERDEAD returned from pthread_mutex_lock(), and EOWNERDEAD is indeed used here for that purpose. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-8-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 4c7404b ] This correspond to the NT syscall NtCreateEvent(). An NT event holds a single bit of state denoting whether it is signaled or unsignaled. There are two types of events: manual-reset and automatic-reset. When an automatic-reset event is acquired via a wait function, its state is reset to unsignaled. Manual-reset events are not affected by wait functions. Whether the event is manual-reset, and its initial state, are specified at creation time. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-9-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 2dcba6f ] This corresponds to the NT syscall NtSetEvent(). This sets the event to the signaled state, and returns its previous state. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-10-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit bbb9797 ] This corresponds to the NT syscall NtResetEvent(). This sets the event to the unsignaled state, and returns its previous state. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20241213193511.457338-11-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 12b29d3 ] This corresponds to the NT syscall NtPulseEvent(). This wakes up any waiters as if the event had been set, but does not set the event, instead resetting it if it had been signalled. Thus, for a manual-reset event, all waiters are woken, whereas for an auto-reset event, at most one waiter is woken. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20241213193511.457338-12-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit a948f41 ] This corresponds to the NT syscall NtQuerySemaphore(). This returns the current count and maximum count of the semaphore. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-13-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 0b3c314 ] This corresponds to the NT syscall NtQueryMutant(). This returns the recursion count, owner, and abandoned state of the mutex. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-14-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit e864071 ] This corresponds to the NT syscall NtQueryEvent(). This returns the signaled state of the event and whether it is manual-reset. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-15-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit a138179 ] NT waits can optionally be made "alertable". This is a special channel for thread wakeup that is mildly similar to SIGIO. A thread has an internal single bit of "alerted" state, and if a thread is alerted while an alertable wait, the wait will return a special value, consume the "alerted" state, and will not consume any of its objects. Alerts are implemented using events; the user-space NT emulator is expected to create an internal ntsync event for each thread and pass that event to wait functions. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20241213193511.457338-16-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 7f853a2 ] Wine has tests for its synchronization primitives, but these are more accessible to kernel developers, and also allow us to test some edge cases that Wine does not care about. This patch adds tests for semaphore-specific ioctls NTSYNC_IOC_SEM_POST and NTSYNC_IOC_SEM_READ, and waiting on semaphores. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-17-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit ae071ae ] Test mutex-specific ioctls NTSYNC_IOC_MUTEX_UNLOCK and NTSYNC_IOC_MUTEX_READ, and waiting on mutexes. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-18-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 4455456 ] Test basic synchronous functionality of NTSYNC_IOC_WAIT_ANY, when objects are considered signaled or not signaled, and how they are affected by a successful wait. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-19-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit d168f68 ] Test basic synchronous functionality of NTSYNC_IOC_WAIT_ALL, and when objects are considered simultaneously signaled. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-20-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
…IOC_WAIT_ANY. [ Upstream commit f232798 ] Test contended "wait-for-any" waits, to make sure that scheduling and wakeup logic works correctly. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-21-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
…IOC_WAIT_ALL. [ Upstream commit 72a651c ] Test contended "wait-for-all" waits, to make sure that scheduling and wakeup logic works correctly, and that the wait only exits once objects are all simultaneously signaled. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-22-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit d2083b5 ] Test event-specific ioctls NTSYNC_IOC_EVENT_SET, NTSYNC_IOC_EVENT_RESET, NTSYNC_IOC_EVENT_PULSE, NTSYNC_IOC_EVENT_READ for manual-reset events, and waiting on manual-reset events. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-23-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit b4e4dd5 ] Test event-specific ioctls NTSYNC_IOC_EVENT_SET, NTSYNC_IOC_EVENT_RESET, NTSYNC_IOC_EVENT_PULSE, NTSYNC_IOC_EVENT_READ for auto-reset events, and waiting on auto-reset events. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-24-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit a2e5a8c ] Expand the contended wait tests, which previously only covered events and semaphores, to cover events as well. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-25-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit dd914e0 ] Test the "alert" functionality of NTSYNC_IOC_WAIT_ALL and NTSYNC_IOC_WAIT_ANY, when a wait is woken with an alert and when it is woken by an object. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-26-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit c52b9cb ] Expand the alert tests to cover alerting a thread mid-wait, to test that the relevant scheduling logic works correctly. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-27-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit a22860e ] Test a more realistic usage pattern, and one with heavy contention, in order to actually exercise ntsync's internal synchronization. This test has several threads in a tight loop acquiring a mutex, modifying some shared data, and then releasing the mutex. At the end we check if the data is consistent. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-28-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 79d42d9 ] Add myself as maintainer, supported by CodeWeavers. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20241213193511.457338-29-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 6b695a7 ] Add an overall explanation of the driver architecture, and complete and precise specification for its intended behaviour. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20241213193511.457338-30-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit c301e1f ] f5b335d ("misc: ntsync: mark driver as "broken" to prevent from building") was committed to avoid the driver being used while only part of its functionality was released. Since the rest of the functionality has now been committed, revert this. Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20241213193511.457338-31-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 0e7d523 ] struct ntsync_obj contains a reference to struct file and that reference contributes to refcount - ntsync_alloc_obj() grabs it. Normally the object is destroyed (and reference to obj->file dropped) in ntsync_obj_release(). However, in case of ntsync_obj_get_fd() failure the object is destroyed directly by its creator. That case should also drop obj->file; plain kfree(obj) is not enough there - it ends up leaking struct file * reference. Take that logics into a helper (ntsync_free_obj()) and use it in both codepaths that destroy ntsync_obj instances. Fixes: b46271e "ntsync: Introduce NTSYNC_IOC_CREATE_SEM" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20250115025002.GA1977892@ZenIV Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 970b975 ] When ntsync_obj_get_fd() fails, we free the ntsync object but forget to drop the "file" member. This was fixed for semaphores in 0e7d523, but that commit did not fix the similar leak for events and mutexes, since they were part of patches not yet in the mainline kernel. Fix those cases. Fixes: 5bc2479 "ntsync: Introduce NTSYNC_IOC_CREATE_MUTEX." Fixes: 4c7404b "ntsync: Introduce NTSYNC_IOC_CREATE_EVENT." Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20250116190717.8923-1-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit fa2e558 ] This allows ntsync to be usuable by non-root processes out of the box Signed-off-by: Mike Lothian <mike@fireburn.co.uk> Reviewed-by: Elizabeth Figura <zfigura@codeweavers.com> Link: https://lore.kernel.org/r/20250214122759.2629-2-mike@fireburn.co.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.15 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
[ Upstream commit 92527e4 ] GCC versions below 13 incorrectly detect the copy size as being static and too small to fit in the "fds" array. Work around this by explicitly calculating the size and returning EINVAL based on that, instead of based on the object count. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202502072019.LYoCR9bF-lkp@intel.com/ Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com> -- Suggested-by as per Arnd's request, but the only thing I changed was preserving array_size() [as noted by Geert in the linked thread]. I tested and found no regressions. v2: Add missing sign-off Link: https://lore.kernel.org/r/20250220192334.549167-1-zfigura@codeweavers.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Backport from v6.14 ] Signed-off-by: WangYuli <wangyuli@uniontech.com>
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Pull Request Overview
Backports the NTSYNC synchronization primitive driver into the 6.6 kernel series, including its driver, UAPI interface, selftests, and documentation while removing obsolete no_llseek entries.
- Introduces a new NTSYNC misc device driver with build and configuration integration.
- Adds a comprehensive selftest suite and updates documentation and maintenance listings.
Reviewed Changes
Copilot reviewed 13 out of 13 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| tools/testing/selftests/drivers/ntsync/config | Adds a test configuration option (note the naming discrepancy). |
| tools/testing/selftests/drivers/ntsync/Makefile | Adds build instructions for the ntsync selftest program. |
| tools/testing/selftests/drivers/ntsync/.gitignore | Configures files to be ignored for ntsync selftests. |
| tools/testing/selftests/Makefile | Includes the ntsync tests in the overall target list. |
| include/uapi/linux/ntsync.h | Provides the UAPI header with ioctl definitions for ntsync. |
| drivers/misc/Makefile | Integrates the new ntsync driver object file into the build. |
| drivers/misc/Kconfig | Introduces a Kconfig option for building the ntsync driver. |
| MAINTAINERS | Updates the maintainers file with ntsync information. |
| Documentation/userspace-api/ntsync.rst | Adds detailed documentation for the ntsync userspace API. |
| Documentation/userspace-api/ioctl/ioctl-number.rst | Allocates ioctl numbers for the new ntsync API. |
| Documentation/userspace-api/index.rst | Lists ntsync as part of the userspace API documentation. |
Comments suppressed due to low confidence (2)
tools/testing/selftests/drivers/ntsync/config:1
- The configuration option is named 'CONFIG_WINESYNC' but the driver is referred to as NTSYNC elsewhere. Consider renaming it to 'CONFIG_NTSYNC=y' for consistency.
CONFIG_WINESYNC=y
Documentation/userspace-api/ntsync.rst:51
- The term 'designaled' appears to be a typographical error. Consider replacing it with 'reset' or 'unsignaled' to improve clarity.
An auto-reset event is designaled when a wait is satisfied; a manual-reset event is not.
Member
Author
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经LLVM19手工测试，使能CONFIG_NTSYNC可通过编译。 |
![sourcery-ai[bot]](https://avatars.githubusercontent.com/in/48477?s=60&v=4){kind=small}
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Hey @Avenger-285714 - I've reviewed your changes - here's some feedback:
- The stress test uses a plain
stress_counterincremented by multiple threads without synchronization, causing a data race—switch to an atomic counter or protected update to ensure correctness. - Given the complexity of
wait_any/wait_alland the multi‐object locking protocol, consider adding a concise top‐level comment describing the lock acquisition order and invariants to aid future maintainers. - This backport spans uapi, driver implementation, docs, and a large test suite—splitting into distinct commits (core driver, uapi, tests) would simplify review and backport tracking.
Here's what I looked at during the review
- 🟡 General issues: 5 issues found
- 🟢 Security: all looks good
- 🟢 Testing: all looks good
- 🟢 Complexity: all looks good
- 🟢 Documentation: all looks good
Help me be more useful! Please click 👍 or 👎 on each comment and I'll use the feedback to improve your reviews.
| .minor = MISC_DYNAMIC_MINOR, | ||
| .name = NTSYNC_NAME, | ||
| .fops = &ntsync_fops, | ||
| .mode = 0666, |
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🚨 issue (security): World-writable device node may have security implications.
If world-writable access isn't necessary, restrict permissions or make them configurable to reduce security risks.
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| #define NTSYNC_IOC_EVENT_SET _IOR ('N', 0x88, __u32) | ||
| #define NTSYNC_IOC_EVENT_RESET _IOR ('N', 0x89, __u32) | ||
| #define NTSYNC_IOC_EVENT_PULSE _IOR ('N', 0x8a, __u32) |
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suggestion: Inconsistent use of _IOR for event set/reset/pulse ioctls.
Since these ioctls modify state and return a value, using _IOWR may better represent their bidirectional behavior.
Suggested change
| #define NTSYNC_IOC_EVENT_SET _IOR ('N', 0x88, __u32) | |
| #define NTSYNC_IOC_EVENT_RESET _IOR ('N', 0x89, __u32) | |
| #define NTSYNC_IOC_EVENT_PULSE _IOR ('N', 0x8a, __u32) | |
| #define NTSYNC_IOC_EVENT_SET _IOWR('N', 0x88, __u32) | |
| #define NTSYNC_IOC_EVENT_RESET _IOWR('N', 0x89, __u32) | |
| #define NTSYNC_IOC_EVENT_PULSE _IOWR('N', 0x8a, __u32) |
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| 'N' 80-8F uapi/linux/ntsync.h NT synchronization primitives | ||
| <mailto:wine-devel@winehq.org> |
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suggestion: Misplaced mailto link in ioctl number registry.
Consider moving the mailto link to the MAINTAINERS file or relevant driver documentation, as contact details are not typically included in the ioctl number registry.
Suggested change
| 'N' 80-8F uapi/linux/ntsync.h NT synchronization primitives | |
| <mailto:wine-devel@winehq.org> | |
| 'N' 80-8F uapi/linux/ntsync.h NT synchronization primitives |
| - Maximum count of the semaphore. | ||
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| Fails with ``EINVAL`` if ``count`` is greater than ``max``. | ||
| On success, returns a file descriptor the created semaphore. |
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nitpick (typo): Missing preposition.
Consider revising to "returns a file descriptor for the created semaphore" or "to the created semaphore." Please update similar sentences on lines 131 and 145.
Suggested implementation:
Fails with ``EINVAL`` if ``count`` is greater than ``max``.
On success, returns a file descriptor for the created semaphore.
On success, returns a file descriptor for the created mutex.
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| performed as a single atomic operation. If two threads are waiting on | ||
| an auto-reset event which is pulsed, only one will be woken. If two | ||
| threads are waiting a manual-reset event which is pulsed, both will | ||
| be woken. However, in both cases, the event will be unsignaled |
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nitpick (typo): Missing preposition.
It should be "waiting on a manual-reset event".
Suggested change
| performed as a single atomic operation. If two threads are waiting on | |
| an auto-reset event which is pulsed, only one will be woken. If two | |
| threads are waiting a manual-reset event which is pulsed, both will | |
| be woken. However, in both cases, the event will be unsignaled | |
| performed as a single atomic operation. If two threads are waiting on | |
| an auto-reset event which is pulsed, only one will be woken. If two | |
| threads are waiting on a manual-reset event which is pulsed, both will | |
| be woken. However, in both cases, the event will be unsignaled |
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| - Optional event object file descriptor. If nonzero, this | ||
| specifies an "alert" event object which, if signaled, will | ||
| terminate the wait. If nonzero, the identifier must point to a | ||
| valid event. |
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suggestion: Clarity of "identifier" for alert argument.
Consider rephrasing to "the file descriptor must refer to a valid event object" to avoid confusion with the term "identifier," which is also used for "owner."
Suggested change
| - Optional event object file descriptor. If nonzero, this | |
| specifies an "alert" event object which, if signaled, will | |
| terminate the wait. If nonzero, the identifier must point to a | |
| valid event. | |
| - Optional event object file descriptor. If nonzero, this | |
| specifies an "alert" event object which, if signaled, will | |
| terminate the wait. If nonzero, the file descriptor must refer to a | |
| valid event object. |
opsiff
approved these changes
Jun 5, 2025
|
[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: opsiff The full list of commands accepted by this bot can be found here. The pull request process is described here DetailsNeeds approval from an approver in each of these files:
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Summary by Sourcery
Backport the NTSYNC miscellaneous driver from upstream into the v6.6 kernel branch and integrate its user-space API, build configuration, documentation, and tests.
New Features:
Build:
Documentation:
Tests: