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* Add refcnt_take_if_gt()Matt Dunwoodie2021-04-131-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function (or of similar nature) is required to safely use a refcnt and smr_entry together. Such functions exist on other platforms as kref_get_unless_zero (on Linux) and refcount_acquire_if_gt (on FreeBSD). The following diagram details the following situation with and without refcnt_take_if_gt in 3 cases, with the first showing the "invalid" use of refcnt_take. Situation: Thread #1 is removing the global referenc (o). Thread #2 wants to reference an object (r), using a thread pointer (t). Case: 1) refcnt_take after Thread #1 has released "o" 2) refcnt_take_if_gt before Thread #1 has released "o" 3) refcnt_take_if_gt after Thread #1 has released "o" Data: struct obj { struct smr_entry smr; struct refcnt refcnt; } *o, *r, *t1, *t2; Thread #1 | Thread #2 ---------------------------------+------------------------------------ | r = NULL; rw_enter_write(&lock); | smr_read_enter(); | t1 = SMR_PTR_GET_LOCKED(&o); | t2 = SMR_PTR_GET(&o); SMR_PTR_SET_LOCKED(&o, NULL); | | if (refcnt_rele(&t1->refcnt) | smr_call(&t1->smr, free, t1); | | if (t2 != NULL) { | refcnt_take(&t2->refcnt); | r = t2; | } rw_exit_write(&lock); | smr_read_exit(); ..... // called by smr_thread | free(t1); | ..... | // use after free | *r ---------------------------------+------------------------------------ | r = NULL; rw_enter_write(&lock); | smr_read_enter(); | t1 = SMR_PTR_GET_LOCKED(&o); | t2 = SMR_PTR_GET(&o); SMR_PTR_SET_LOCKED(&o, NULL); | | if (refcnt_rele(&t1->refcnt) | smr_call(&t1->smr, free, t1); | | if (t2 != NULL && | refcnt_take_if_gt(&t2->refcnt, 0)) | r = t2; rw_exit_write(&lock); | smr_read_exit(); ..... // called by smr_thread | // we don't have a valid reference free(t1); | assert(r == NULL); ---------------------------------+------------------------------------ | r = NULL; rw_enter_write(&lock); | smr_read_enter(); | t1 = SMR_PTR_GET_LOCKED(&o); | t2 = SMR_PTR_GET(&o); SMR_PTR_SET_LOCKED(&o, NULL); | | if (t2 != NULL && | refcnt_take_if_gt(&t2->refcnt, 0)) | r = t2; if (refcnt_rele(&t1->refcnt) | smr_call(&t1->smr, free, t1); | rw_exit_write(&lock); | smr_read_exit(); ..... | // we need to put our reference | if (refcnt_rele(&t2->refcnt)) | smr_call(&t2->smr, free, t2); ..... // called by smr_thread | free(t1); | ---------------------------------+------------------------------------ Currently it uses atomic_add_int_nv to atomically read the refcnt, but I'm open to suggestions for better ways. The atomic_cas_uint is used to ensure that refcnt hasn't been modified since reading `old`.
* makes `struct execsw' to:semarie2021-03-211-2/+2
| | | | | | | - use C99-style initialization (grep works better with that) - use const as execsw is not modified during runtime ok mpi@
* regenmvs2021-03-182-4/+4
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* Fix bit position of ORPHAN in PS_BITS.visa2021-03-171-2/+2
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* Kill SINGLE_PTRACE and use SINGLE_SUSPEND which has almost the same semanticmpi2021-03-121-2/+1
| | | | | | | | single_thread_set() is modified to explicitly indicated when waiting until sibling threads are parked is required. This is obviously not required if a traced thread is switching away from a CPU after handling a STOP signal. ok claudio@
* spellingjsg2021-03-107-14/+14
| | | | ok gnezdo@ semarie@ mpi@
* Early daemons like dhcpleased(8), slaacd(8), unwind(8), resolvd(8)bluhm2021-03-091-3/+3
| | | | | | | | | | | | | are started before syslogd(8). This resulted in ugly sendsyslog(2) dropped logs and the real message was lost. Create a temporary stash for log messages within the kernel. It has a limited size of 100 messages, and each message is truncated to 8192 bytes. When the stash is exhausted, the well-known dropped message is generated with a counter. After syslogd(8) has setup everything, it sends a debug line through libc to flush the kernel stash. Then syslogd receives all messages from the kernel before the usual logs. OK deraadt@ visa@
* Merge issignal() and CURSIG() in preparation for turning it mp-safe.mpi2021-03-041-13/+2
| | | | | | This makes appear some redundant & racy checks. ok semarie@
* let m_copydata use a void * instead of caddr_tdlg2021-02-251-2/+2
| | | | | | | i'm not a fan of having to cast to caddr_t when we have modern inventions like void *s we can take advantage of. ok claudio@ mvs@ bluhm@
* kqueue: Revise filterops interfacevisa2021-02-241-11/+69
| | | | | | | | | | | | | | | | | Extend kqueue's filterops interface with new callbacks so that it becomes easier to use with fine-grained locking. The new interface delegates the serialization of kn_event access to event sources. Now kqueue uses filterops callbacks to read or write kn_event. This hides event sources' locking patterns from kqueue, and allows clean implementation of atomic read-and-clear for EV_CLEAR, for instance. There are so many existing filterops instances that converting all of them in one go is tricky. This patch adds a wrapper mechanism that kqueue uses when the new callbacks are missing. The new filterops interface has been influenced by XNU's kqueue. OK mpi@ semarie@
* remove unused malloc_roundup()jsg2021-02-231-2/+1
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* Release mbuf(9) chain with a simple m_freem(9) loop in sorflush().mvs2021-02-181-2/+1
| | | | | | | | | | | | Passing local copy of socket to sbrelease() is too complicated to just free receive buffer. We don't allocate large object on the stack. Also we don't pass unlocked socket to soassertlocked() within sbdrop(). This was not triggered because we lock the whole layer with one lock. Also sorflush() is now private to kern/uipc_socket.c, so it's definition was made to be in accordance. ok claudio@ mpi@
* Move single_thread_set() out of KERNEL_LOCK().mpi2021-02-151-2/+2
| | | | | | | Use the SCHED_LOCK() to ensure `ps_thread' isn't being modified by a sibling when entering tsleep(9) w/o KERNEL_LOCK(). ok visa@
* Move UNIX domain sockets out of kernel lock. The new `unp_lock' rwlock(9)mvs2021-02-101-14/+21
| | | | | | | | used as solock()'s backend to protect the whole layer. With feedback from mpi@. ok bluhm@ claudio@
* Revert the convertion of per-process thread into a SMR_TAILQ.mpi2021-02-081-15/+6
| | | | | We did not reach a consensus about using SMR to unlock single_thread_set() so there's no point in keeping this change.
* Simplify sleep_setup API to two operations in preparation for splittingmpi2021-02-082-11/+4
| | | | | | | | | | | | the SCHED_LOCK(). Putting a thread on a sleep queue is reduce to the following: sleep_setup(); /* check condition or release lock */ sleep_finish(); Previous version ok cheloha@, jmatthew@, ok claudio@
* 6.9-betaderaadt2021-02-061-3/+3
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* Remove last remnants of ASU ac_flag from accounting.rob2021-02-041-2/+1
| | | | OK deraadt@, bluhm@
* Remove obsolete vnode operation vector declarations.visa2021-02-011-6/+1
| | | | OK bluhm@, claudio@, mpi@, semarie@
* introduce ujoy(4), a restricted subset of uhid(4) for gamecontrollers.thfr2021-01-231-1/+9
| | | | | | | | This includes ujoy_hid_is_collection() to work around limitations of hid_is_collection() until this can be combined without fallout. input, testing with 8bitdo controller, and ok brynet@ PS4 controller testing, fix for hid_is_collection, and ok mglocker@
* Mark `ps_oppid' as atomic.mvs2021-01-181-2/+2
| | | | ok mpi@
* regenmvs2021-01-182-4/+4
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* Revert wrong commit.mvs2021-01-182-4/+4
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* Convert ifunit() to if_unit(9).mvs2021-01-182-4/+4
| | | | ok sashan@
* Cache parent's pid as `ps_ppid' and use it instead of `ps_pptr->ps_pid'.mvs2021-01-171-1/+2
| | | | | | This allows us to unlock getppid(2). ok mpi@
* kqueue: Revise fd close notificationvisa2021-01-172-3/+4
| | | | | | | | | | | | | | | | | | Deliver file descriptor close notification for __EV_POLL knotes through struct kevent that kqueue_scan() returns. This replaces the previous way of returning EBADF from kqueue_scan(), making it easier to determine what exactly has changed. When a file descriptor is closed, its __EV_POLL knotes are turned into one-shot events and queued for delivery. These knotes are "unregistered" as they are reachable only through the queue of active events. This reduces interference with the normal workings of kqueue. However, more care is needed to avoid leaking knotes. In addition, the unregistering removes a limit on the number of issued knotes. To prevent accumulation of pending fd close notifications, kqpoll_init() flushes the active queue at the start of a kqpoll scan. OK mpi@
* Replace SB_KNOTE and sb_flagsintr with direct checking of klist.visa2021-01-171-6/+3
| | | | OK mpi@ as part of a larger diff
* kernel, sysctl(8): remove dead variable: tickadjcheloha2021-01-132-4/+2
| | | | | | | | | | | | | | | | | | | | The global "tickadj" variable is a remnant of the old NTP adjustment code we used in the kernel before the current timecounter subsystem was imported from FreeBSD circa 2004 or 2005. Fifteen years hence it is completely vestigial and we can remove it. We probably should have removed it long ago but I guess it slipped through the cracks. FreeBSD removed it in 2002: https://cgit.freebsd.org/src/commit/?id=e1d970f1811e5e1e9c912c032acdcec6521b2a6d NetBSD and DragonflyBSD can probably remove it, too. We export tickadj via the kern.clockrate sysctl(2), so update sysctl.2 and sysctl(8) accordingly. Hypothetically this change could break someone's sysctl(8) parsing script. I don't think that's very likely. ok mvs@
* New rw_obj_init() API providing reference-counted rwlock.mpi2021-01-111-1/+23
| | | | | | | Original port from NetBSD by guenther@, required for upcoming amap & anon locking. ok kettenis@
* Simplify sleep signal handling a bit by introducing sleep_signal_check().claudio2021-01-111-3/+2
| | | | | | | The common code is moved to sleep_signal_check() and instead of multiple state variables for sls_sig and sls_unwind only one sls_sigerr is set. This simplifies the checks in sleep_finish_signal() a great bit. Idea from and OK mpi@
* pool(9): remove tickscheloha2021-01-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | Change the pool(9) timeouts to use the system uptime instead of ticks. - Change the timeouts from variables to macros so we can use SEC_TO_NSEC(). This means these timeouts are no longer patchable via ddb(4). dlg@ does not think this will be a problem, as the timeout intervals have not changed in years. - Use low-res time to keep things fast. Add a local copy of getnsecuptime() to subr_pool.c to keep the diff small. We will need to move getnsecuptime() into kern_tc.c and document it later if we ever have other users elsewhere in the kernel. - Rename ph_tick -> ph_timestamp and pr_cache_tick -> pr_cache_timestamp. Prompted by tedu@ some time ago, but the effort stalled (may have been my fault). Input from kettenis@ and dlg@. Special thanks to mpi@ for help with struct shuffling. This change does not increase the size of struct pool_page_header or struct pool. ok dlg@ mpi@
* Add singly-linked tail queue macros from FreeBSD.millert2020-12-301-1/+98
| | | | | | These are essentially equivalent to the simple queue macros from NetBSD but predate them and are more widely available on other systems. OK mpi@ denis@
* Analog to the the kern.audio.record sysctl parameter for audio(4)mglocker2020-12-281-2/+15
| | | | | | | | | | | devices, introduce kern.video.record for video(4) devices. By default kern.video.record will be set to zero, blanking all data delivered by device drivers which attach to video(4). The idea was initially proposed by Laurence Tratt <laurie AT tratt DOT net>. ok mpi@
* Make NET_LOCK() assertions conditional to DIAGNOSTICvisa2020-12-271-1/+8
| | | | | | This saves about 2.5 KiB off amd64's RAMDISK after gzip compression. OK deraadt@, mpi@, cheloha@
* Refactor klist insertion and removalvisa2020-12-251-1/+3
| | | | | | | | | | | | Rename klist_{insert,remove}() to klist_{insert,remove}_locked(). These functions assume that the caller has locked the klist. The current state of locking remains intact because the kernel lock is still used with all klists. Add new functions klist_insert() and klist_remove() that lock the klist internally. This allows some code simplification. OK mpi@
* Small smr_grace_wait() optimizationvisa2020-12-251-1/+2
| | | | | | | | | | | | Make the SMR thread maintain an explicit system-wide grace period and make CPUs observe the current grace period when crossing a quiescent state. This lets the SMR thread avoid a forced context switch for CPUs that have already entered the latest grace period. This change provides a small improvement in smr_grace_wait()'s performance in terms of context switching. OK mpi@, anton@
* tsleep(9): add global "nowake" channel for threads avoiding wakeup(9)cheloha2020-12-241-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It would be convenient if there were a channel a thread could sleep on to indicate they do not want any wakeup(9) broadcasts. The easiest way to do this is to add an "int nowake" to kern_synch.c and extern it in sys/systm.h. You use it like this: #include <sys/systm.h> tsleep_nsec(&nowait, ...); There is now no need to handroll a local dead channel, e.g. int chan; tsleep_nsec(&chan, ...); which expands the stack. Local dead channels will be replaced with &nowake in later patches. One possible problem with this "one global channel" approach is sleep queue congestion. If you have lots of threads sleeping on &nowake you might slow down a wakeup(9) on a different channel that hashes into the same queue. Unsure how much of problem this actually is, if at all. NetBSD and FreeBSD have a "pause" interface in the kernel that chooses a suitable channel automatically. To keep things simple and avoid adding a new interface we will start with this global channel. Discussed with mpi@, claudio@, kettenis@, and deraadt@. Basically designed by kettenis@, who vetoed my other proposals. Bugs caught by deraadt@, tb@, and patrick@.
* Introduce klistopsvisa2020-12-201-1/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch extends struct klist with a callback descriptor and an argument. The main purpose of this is to let the kqueue subsystem assert when a klist should be locked, and operate the klist lock in klist_invalidate(). Access to a knote list of a kqueue-monitored object has to be serialized somehow. Because the object often has a lock for protecting its state, and because the object often acquires this lock at the latest in its f_event callback function, it makes sense to use this lock also for the knote lists. The existing uses of NOTE_SUBMIT already show a pattern that is likely to become more prevalent. There could be an embedded lock in klist. However, such a lock would be redundant in many cases. The code cannot rely on a single lock type (mutex, rwlock, something else) because the needs of monitored objects vary. In addition, an embedded lock would introduce new lock order constraints. Note that the patch does not rule out use of dedicated klist locks. The patch introduces a way to associate lock operations with a klist. The caller can provide a custom implementation, or use a ready-made interface with a mutex or rwlock. For compatibility with old code, the new code falls back to using the kernel lock if no specific klist initialization has been done. The existing code already relies on implicit initialization of klist. Sadly, this change increases the size of struct klist. dlg@ thinks this is not fatal, though. OK mpi@
* Add fd close notification for kqueue-based poll() and select()visa2020-12-181-1/+2
| | | | | | | | | | When the file descriptor of an __EV_POLL-flagged knote is closed, post EBADF through the kqueue instance to the caller of kqueue_scan(). This lets kqueue-based poll() and select() preserve their current behaviour of returning EBADF when a polled file descriptor is closed concurrently. OK mpi@
* Make knote_{activate,remove}() internal to kern_event.c.visa2020-12-181-3/+1
| | | | OK mpi@
* Add helpers around rw_status(9) to help checking if a lock is held.mpi2020-12-151-1/+24
| | | | ok visa@
* Rename the macro MCLGETI to MCLGETL and removes the dead parameter ifp.jan2020-12-121-2/+2
| | | | | | OK dlg@, bluhm@ No Opinion mpi@ Not against it claudio@
* Add kernel-only per-thread kqueue & helpers to initialize and free it.mpi2020-12-092-2/+8
| | | | | | This will soon be used by select(2) and poll(2). ok anton@, visa@
* Convert the per-process thread list into a SMR_TAILQ.mpi2020-12-071-6/+15
| | | | | | | Currently all iterations are done under KERNEL_LOCK() and therefor use the *_LOCKED() variant. From and ok claudio@
* Refactor kqueue_scan() so it can be used by other syscalls.mpi2020-12-071-2/+2
| | | | | | | Stop iterating in the function and instead copy the returned events to userland after every call. ok visa@
* Hoist DTYPE_* out of #ifdef _KERNEL.martijn2020-12-021-6/+9
| | | | | | Similar to what NetBSD and FreeBSD have done. OK guenther@
* Change kqueue_scan() to keep track of collected events in the given context.mpi2020-11-251-1/+4
| | | | | | | | | | | | | | It is now possible to call the function multiple times to collect events. For that, the end marker has to be preserved between calls because otherwise the scan might collect an event more than once. If a collected event gets reactivated during scanning, it will be added at the tail of the queue, out of reach because of the end marker. This is required to implement select(2) and poll(2) on top of kqueue_scan(). Done & originally committed by visa@ in r1.143, in snap for more than 2 weeks. ok visa@, anton@
* Fix comment _SYS_VIDEOIO_H -> _SYS_VIDEOIO_H_mglocker2020-11-201-2/+2
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* Constify dktypenames and fstypenames in libc.guenther2020-11-141-3/+3
| | | | | | Adjust variable declaration in disklabel to match. ok millert@ deraadt@
* setitimer(2): ITIMER_REAL: protect state with per-process mutex ps_mtxcheloha2020-11-101-3/+3
| | | | | | | | | | | | | | | | | | | | To unlock getitimer(2) and setitimer(2) we need to protect the per-process ITIMER_REAL state with something other than the kernel lock. As the ITIMER_REAL timeout callback realitexpire() runs at IPL_SOFTCLOCK the per-process mutex ps_mtx is appropriate. In setitimer() we need to use ps_mtx instead of the global itimer_mtx if the given timer is ITIMER_REAL. Easy. The ITIMER_REAL timeout callback routine realitexpire() is trickier. When we enter ps_mtx during the callback we need to check if the timer was cancelled or rescheduled. A thread from the process can call setitimer(2) at the exact moment the callback is about to run from timeout_run() (see kern_timeout.c). Update the locking annotation in sys/proc.h accordingly. ok anton@
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