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* Synchronization: Refactor Waiter to allow us to write testsGravatar Derek Mauro2023-03-20
| | | | | | | | | | | | | Instead of being only able to test the platform Waiter implementation, this allows us to be able to test all Waiter implementations that build on a specific platform. A unittest is added that tests all implementations that work for the platform, and allows us to check that the expected one is being used by printing the name of the selected implementation. PiperOrigin-RevId: 518072415 Change-Id: Ie9e6fcd9d8283b4038e6f4e68a304d2adcc04b19
* Increase the timeout of Windows for the kernel timeout tests.Gravatar Tom Rybka2023-03-16
| | | | | | | Windows tests often run in Emulation, and even with KVM we can still timeout. PiperOrigin-RevId: 517192968 Change-Id: I3b4e435f8ac8ad1e7eab6f043c051fa75efed64b
* Synchronization: Add support for true relative timeouts usingGravatar Derek Mauro2023-03-14
| | | | | | | | | | | | | | | | | | | | | | | | | | monotonic clocks on Linux when the implementation uses futexes After this change, when synchronization methods that wait are passed an absl::Duration to limit the wait time, these methods will wait for that interval, even if the system clock is changed (subject to any limitations with how CLOCK_MONOTONIC keeps track of time). In other words, an observer measuring the time with a stop watch will now see the correct interval, even if the system clock is changed. Previously, the duration was added to the current time, and methods would wait until that time was reached on the possibly changed realtime system clock. The behavior of the synchronization methods that take an absl::Time is unchanged. These methods always wait until the absolute point in time is reached and respect changes to the system clock. In other words, an observer will always see the timeout occur when a wall clock reaches that time, even if the clock is manipulated externally. Note: ABSL_PREDICT_FALSE was removed from the error case in Futex as timeouts are handled by this case, and timeouts are part of normal operation. PiperOrigin-RevId: 516534869 Change-Id: Ib70b83e4be3f9e3f1727646975a21a1d30acb242
* Synchronization: Change KernelTimeout to always store absoluteGravatar Derek Mauro2023-03-13
| | | | | | | | | | timeouts, but when a relative timeout is provided, the timeout is an absolute timeout against a steady clock (when possible). This allows methods that return relative timeouts to automatically recompute the remaining duration, for instance, on suprious wakeups. PiperOrigin-RevId: 516304139 Change-Id: I7d739cb50dd749eba5dba7ac6c34d18dc53703ed
* Rollback Mutex relative timeout support because of internal incompatibilityGravatar Abseil Team2023-03-09
| | | | | PiperOrigin-RevId: 515427893 Change-Id: I89e8756fcf400459b0226d14785c6511ad3e380b
* Synchronization: Add support for true relative timeouts usingGravatar Derek Mauro2023-03-08
| | | | | | | | | | | | | | | | | | | | | | | | | | monotonic clocks on Linux when the implementation uses futexes After this change, when synchronization methods that wait are passed an absl::Duration to limit the wait time, these methods will wait for that interval, even if the system clock is changed (subject to any limitations with how CLOCK_MONOTONIC keeps track of time). In other words, an observer measuring the time with a stop watch will now see the correct interval, even if the system clock is changed. Previously, the duration was added to the current time, and methods would wait until that time was reached on the possibly changed realtime system clock. The behavior of the synchronization methods that take an absl::Time is unchanged. These methods always wait until the absolute point in time is reached and respect changes to the system clock. In other words, an observer will always see the timeout occur when a wall clock reaches that time, even if the clock is manipulated externally. Note: ABSL_PREDICT_FALSE was removed from the error case in Futex as timeouts are handled by this case, and timeouts are part of normal operation. PiperOrigin-RevId: 515043788 Change-Id: I151127b588065bd1316273f36d7c946545c2c892
* Rollback because of internal incompatibility.Gravatar Abseil Team2023-02-28
| | | | | PiperOrigin-RevId: 512979517 Change-Id: I7fe38ed246e42e6f8eb322e15c3b299215163168
* Fix out of bounds array access when deadlock detector finds exceptionally ↵Gravatar Abseil Team2023-02-22
| | | | | | | large cycles. PiperOrigin-RevId: 511536497 Change-Id: If70a1c72ef5f7cbb4a80100c4edff459373a5d55
* Synchronization: Add support for true relative timeouts usingGravatar Derek Mauro2023-02-17
| | | | | | | | | | | | | | | | | | | | | | | | | | monotonic clocks on Linux when the implementation uses futexes After this change, when synchronization methods that wait are passed an absl::Duration to limit the wait time, these methods will wait for that interval, even if the system clock is changed (subject to any limitations with how CLOCK_MONOTONIC keeps track of time). In other words, an observer measuring the time with a stop watch will now see the correct interval, even if the system clock is changed. Previously, the duration was added to the current time, and methods would wait until that time was reached on the possibly changed realtime system clock. The behavior of the synchronization methods that take an absl::Time is unchanged. These methods always wait until the absolute point in time is reached and respect changes to the system clock. In other words, an observer will always see the timeout occur when a wall clock reaches that time, even if the clock is manipulated externally. Note: ABSL_PREDICT_FALSE was removed from the error case in Futex as timeouts are handled by this case, and timeouts are part of normal operation. PiperOrigin-RevId: 510405347 Change-Id: I0b3ea390de97014cfa353079ae2e0c1c637aca69
* Add KernelTimeout methods that convert the timeout to theGravatar Derek Mauro2023-02-16
| | | | | | | | | | | | | | | std::chrono methods used by std::condition_variable. A followup change will add an implemention of synchronization_internal::Waiter that can use std:mutex/std::condition_variable to implement the per-thread semaphore that absl::Mutex waits on. This implementation may at some point become the default on platforms such as Windows where there doesn't seem to be an easy way of supporting real absolute timeouts. In this case we can defer to their standard library to implement correct support. PiperOrigin-RevId: 510204786 Change-Id: Icf4d695013fd060abbd53dae23e71ea36f731565
* KernelTimeout optimization: Use absl::GetCurrentTimeNanos()Gravatar Derek Mauro2023-02-15
| | | | | | | instead of absl::ToUnixNanos(absl::Now()); PiperOrigin-RevId: 509829866 Change-Id: Ib34362762304ad6eb7980a1227d717069b84f656
* Rewrite KernelTimeout to support both absolute and relative timeoutsGravatar Derek Mauro2023-02-09
| | | | | | | | | | | | | | APIs that take KernelTimeout as a parameter can now query if an absolute or relative timeout was requested. If the underlying API can only use one type of timeout, the code will do a reasonable conversion. The goal is to eventually enable the possibility of using wait times that are based on monotonic clocks that are safe against system clock steps. PiperOrigin-RevId: 508541507 Change-Id: Id08bf13515f3e1bfd78d88393cde98a6fd3ef72c
* Add overrides to other functions which call Waiter::GetWaiterGravatar Abseil Team2023-02-08
| | | | | PiperOrigin-RevId: 508124592 Change-Id: Ib183e6e241c81b2760e7f849f8af8e7e2c30ea42
* Delete unused Futex methodsGravatar Derek Mauro2023-02-01
| | | | | PiperOrigin-RevId: 506323250 Change-Id: I0f7d4532c19088b011740ceff87ecec55cc34edb
* Minor formatting: Fix misplaced space.Gravatar Abseil Team2023-01-19
| | | | | PiperOrigin-RevId: 503110285 Change-Id: I59c48b1486386e2db8fb62cf8bfa1a691865f704
* Clean up the XRay annotation leftover on mutex.Gravatar Abseil Team2022-12-27
| | | | | PiperOrigin-RevId: 497998566 Change-Id: I8d43311e280a5ea46c42abed55be62cd70d4d54a
* Replace ABSL_INTERNAL_UNREACHABLE with ABSL_UNREACHABLE()Gravatar Derek Mauro2022-12-22
| | | | | PiperOrigin-RevId: 497197704 Change-Id: I3865a874e04f6f55a1ab374b03451535a86bc5a3
* Remove unneeded "friends" from KernelTimeout.Gravatar Abseil Team2022-12-21
| | | | | PiperOrigin-RevId: 496974198 Change-Id: I73b4013a2ad9fd37650d788cbd1e758b327b59d2
* Add MakeAbsNs to KernelTimeout.Gravatar Abseil Team2022-12-15
| | | | | | | | | Rather than add new friends every time a new (internal) use arises, just expose the timestamp. PiperOrigin-RevId: 495722262 Change-Id: I25d2ce64769dc58cbe634259f07c600ce6c1e714
* Fix the documentation of the atomic_hook.h registration functions to ↵Gravatar Greg Falcon2022-12-15
| | | | | | | | | | | correctly state that only the first registered hook will be honored. The comments that imply otherwise were never true, and were a leftover artifact during initial development of the feature. Also remove a TODO() I gave myself years ago; this is never going to happen and isn't worth the bother. PiperOrigin-RevId: 495687371 Change-Id: I63f8ef57d659075bf290caae0617ea61ceb2c1db
* Remove static initializer from mutex.h.Gravatar Abseil Team2022-11-30
| | | | | PiperOrigin-RevId: 491915718 Change-Id: I7469601857b5a3506163518d29f49792f3053b34
* absl: fix Mutex TSan annotationsGravatar Abseil Team2022-11-28
| | | | | | | | | TSan misses synchronization around passing PerThreadSynch between threads since it happens inside of the Mutex code (which me mostly ignore), so we need to ignore all accesses to the object. PiperOrigin-RevId: 491297912 Change-Id: I13ea2015dee5c1a3fc4315c85112902ccffccc45
* Update Condition to allocate 24 bytes for MSVC platform pointers to methods.Gravatar Abseil Team2022-11-16
| | | | | PiperOrigin-RevId: 488986942 Change-Id: I2babb7ea30d60c544f55ca9ed02d9aed23051a12
* Use AnyInvocable in internal thread_poolGravatar Abseil Team2022-11-15
| | | | | PiperOrigin-RevId: 488676817 Change-Id: I13f15bb93ab6dda4c56caf969be3c14f84ada6a0
* Force a conservative allocation for pointers to methods in Condition objects.Gravatar Abseil Team2022-11-07
| | | | | | | | | | | In order for Condition to work on Microsoft platforms, it has to store pointers to methods that are larger than we usually expect. MSVC pointers to methods from class hierarchies that employ multiple inheritance or virtual inheritance are strictly larger than pointers to methods in class hierarchies that only employ single inheritance. This change introduces an opaque declaration of a class, which is not fulfilled. This declaration is used to calculate the size of the Condition method pointer allocation. Because the declaration is of unspecified inheritance, the compiler is forced to use a conservatively large allocation, which will thereby accommodate all method pointer sizes. Because the `method_` and `function_` callbacks are only populated in mutually exclusive conditions, they can be allowed to take up the same space in the Condition object. This change combines the `method_` and `function_` fields and renames the new field to `callback_`. The constructor logic is updated to reflect the new field. PiperOrigin-RevId: 486701312 Change-Id: If06832cc26f27d91e295183e44dc29440af5f9db
* Merge pull request #1307 from KindDragon:patch-1Gravatar Copybara-Service2022-11-03
|\ | | | | | | | | PiperOrigin-RevId: 485885633 Change-Id: Idfaf6ce22a9421fe05ae38029c8a68b720ce50ba
| * Fix MSVC version checking in lifetime_test.ccGravatar Arkady Shapkin2022-11-03
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* Mutex: Fix stall on single-core systemsGravatar Abseil Team2022-10-24
| | | | | | | | | | | | | | | | | | | | | | | | | | On single-core systems, a thread could be preempted while holding an absl::Mutex, or even worse, the spin lock. If a FIFO thread wakes up and tries to acquire this lock, it might not be able to yield() to the sleeping thread. Within MutexDelay(), a yield() and a sleep(10us) are used to yield the CPU. The yield() would do nothing if the calling thread holds the highest priority in the system. The 10us sleep() may not be able to reach the scheduler either, if the system is slow enough. This code path is known to be reachable in the following scenarios: - a FIFO thread calls LockSlowLoop() with spin lock held by a normal thread - a FIFO thread calls LockWhen*() with the Mutex held by a normal thread for a long time - a FIFO thread calls Await*(), releases the Mutex to be held by a normal thread for a long time This CL adds a mutex global for the sleep time, and sets it using the return time of the a yield() call. Yield() must reach the scheduler even when it fails to yield to anyone, and would allow sleep() to do the same. A small constant multiplier (5) is also applied to overcome uncontrollable factors in the runtime and help sleep() to consistently yield to another thread. Upper and lower bounds for the sleep time is also controlled to block any unreasonable values. PiperOrigin-RevId: 483459711 Change-Id: I14efadbadaf9244a2462f377b515147bda651c89
* Change per_thread_sem_test from size medium to size large.Gravatar Evan Brown2022-10-14
| | | | | PiperOrigin-RevId: 481192073 Change-Id: I1e3296f6be4ddf73bd5c7164f4673e97a0c2c408
* Changes mutex unlock profilingGravatar Abseil Team2022-10-07
| | | | | PiperOrigin-RevId: 479667897 Change-Id: I6085df8bfcfb009806230f8d71b576a1371a4d1f
* Fix "unsafe narrowing" warnings in absl, 8/n.Gravatar Abseil Team2022-09-12
| | | | | | | | | | | | | | | Addresses failures with the following, in some files: -Wshorten-64-to-32 -Wimplicit-int-conversion -Wsign-compare -Wsign-conversion -Wtautological-unsigned-zero-compare (This specific CL focuses on .cc files in */internal/.) Bug: chromium:1292951 PiperOrigin-RevId: 473868797 Change-Id: Ibe0b76e33f9e001d59862beaac54fb47bacd39b2
* Fix "unsafe narrowing" warnings in absl, 9/n.Gravatar Abseil Team2022-09-08
| | | | | | | | | | | | | | | Addresses failures with the following, in some files: -Wshorten-64-to-32 -Wimplicit-int-conversion -Wsign-compare -Wsign-conversion -Wtautological-unsigned-zero-compare (This specific CL focuses on miscellaneous non-test source files.) Bug: chromium:1292951 PiperOrigin-RevId: 473054605 Change-Id: Ifd7b24966613ca915511a3a607095508068200b8
* Rollback of fix "unsafe narrowing" warnings in absl, 8/n.Gravatar Derek Mauro2022-09-01
| | | | | | | | | | | | | | | Addresses failures with the following, in some files: -Wshorten-64-to-32 -Wimplicit-int-conversion -Wsign-compare -Wsign-conversion -Wtautological-unsigned-zero-compare (This specific CL focuses on .cc files in */internal/.) Bug: chromium:1292951 PiperOrigin-RevId: 471561809 Change-Id: I7abd6d83706f5ca135f1ce3458192a498a6280b9
* Fix "unsafe narrowing" warnings in absl, 8/n.Gravatar Abseil Team2022-09-01
| | | | | | | | | | | | | | | Addresses failures with the following, in some files: -Wshorten-64-to-32 -Wimplicit-int-conversion -Wsign-compare -Wsign-conversion -Wtautological-unsigned-zero-compare (This specific CL focuses on .cc files in */internal/.) Bug: chromium:1292951 PiperOrigin-RevId: 471549854 Change-Id: Id685d0e4666212926f4e001b8ef4930b6a33a4cc
* Changes mutex profilingGravatar Abseil Team2022-09-01
| | | | | PiperOrigin-RevId: 471545981 Change-Id: I4d2c8b6d4f1e58976915bda78a77178b8bf80da8
* Added some more no_test.. tags to build targets for controlling testing.Gravatar Abseil Team2022-08-31
| | | | | PiperOrigin-RevId: 471256712 Change-Id: I2a1e4846a524bccd3c935a40abab0c0218afdfc0
* Remove includes which are not used directly.Gravatar Abseil Team2022-08-30
| | | | | PiperOrigin-RevId: 471030218 Change-Id: I727c7f8966fe9c96736283c8e1a13a76b3cdb53d
* Fix "unsafe narrowing" warnings in absl, 3/n.Gravatar Abseil Team2022-08-04
| | | | | | | | | | | | | | | Addresses failures with the following, in some files: -Wshorten-64-to-32 -Wimplicit-int-conversion -Wsign-compare -Wsign-conversion -Wtautological-unsigned-zero-compare (This specific CL focuses on .cc files in dirs n-t, except string.) Bug: chromium:1292951 PiperOrigin-RevId: 465287204 Change-Id: I0fe98ff78bf3c08d86992019eb626755f8b6803e
* Fix "unsafe narrowing" warnings in absl, 1/n.Gravatar Abseil Team2022-07-28
| | | | | | | | | | | | | | | Addresses failures with the following, in some files: -Wshorten-64-to-32 -Wimplicit-int-conversion -Wsign-compare -Wsign-conversion -Wtautological-unsigned-zero-compare (This specific CL focuses on .h and win32 .inc files.) Bug: chromium:1292951 PiperOrigin-RevId: 463835431 Change-Id: If8e5f7f651d5cd96035e23e4623bdb08a7fedabe
* Merge pull request #1223 from ElijahPepe:fix/implement-snprintf-safelyGravatar Copybara-Service2022-07-27
|\ | | | | | | | | PiperOrigin-RevId: 463581990 Change-Id: I47359d4d2d2fcd2365b5ff9a5c3b61b5751e4ed2
| * fix: properly create the b integerGravatar Elijah Conners2022-07-21
| | | | | | | | Signed-off-by: Elijah Conners <business@elijahpepe.com>
| * fix(mutex): safely call snprintfGravatar Elijah Conners2022-07-19
|/ | | | | | | | | | | In the PostSynchEvent() function, the pos integer uses an implementation of snprintf that is fundamentally unsafe: since the return value of snprintf is the number of characters that would have been written to the buffer, if an operation reaches the end of the buffer with more than one character discarded, the return value will be greater than the buffer size, requiring a check of the buffer's current size. Signed-off-by: Elijah Conners <business@elijahpepe.com>
* Disable tests on some platforms where they currently fail.Gravatar Tom Rybka2022-06-02
| | | | | PiperOrigin-RevId: 452542838 Change-Id: I45d80b220c0450d27423bb23504e95c25811877b
* Clarify the behaviour of `AssertHeld` and `AssertReaderHeld` when the ↵Gravatar Abseil Team2022-05-27
| | | | | | | calling thread doesn't hold the mutex. PiperOrigin-RevId: 451410449 Change-Id: Iffd4c7463f1051474debbed256703589d96a548c
* absl: fix use-after-free in Mutex/CondVarGravatar Abseil Team2022-05-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Both Mutex and CondVar signal PerThreadSem/Waiter after satisfying the wait condition, as the result the waiting thread may return w/o waiting on the PerThreadSem/Waiter at all. If the waiting thread then exits, it currently destroys Waiter object. As the result Waiter::Post can be called on already destroyed object. PerThreadSem/Waiter must be type-stable after creation and must not be destroyed. The futex-based implementation is the only one that is not affected by the bug since there is effectively nothing to destroy (maybe only UBSan/ASan could complain about calling methods on a destroyed object). Here is the problematic sequence of events: 1: void Mutex::Block(PerThreadSynch *s) { 2: while (s->state.load(std::memory_order_acquire) == PerThreadSynch::kQueued) { 3: if (!DecrementSynchSem(this, s, s->waitp->timeout)) { 4: PerThreadSynch *Mutex::Wakeup(PerThreadSynch *w) { 5: ... 6: w->state.store(PerThreadSynch::kAvailable, std::memory_order_release); 7: IncrementSynchSem(this, w); 8: ... 9: } Consider line 6 is executed, then line 2 observes kAvailable and line 3 is not called. The thread executing Mutex::Block returns from the method, acquires the mutex, releases the mutex, exits and destroys PerThreadSem/Waiter. Now Mutex::Wakeup resumes and executes line 7 on the destroyed object. Boom! CondVar uses a similar pattern. Moreover the semaphore-based Waiter implementation is not even destruction-safe (the Waiter cannot be used to signal own destruction). So even if Mutex/CondVar would always pair Waiter::Post with Waiter::Wait before destroying PerThreadSem/Waiter, it would still be subject to use-after-free bug on the semaphore. PiperOrigin-RevId: 449159939 Change-Id: I497134fa8b6ce1294a422827c5f0de0e897cea31
* absl: fix live-lock in CondVarGravatar Abseil Team2022-05-17
| | | | | | | | CondVar::WaitWithTimeout can live-lock when timeout is racing with Signal/SignalAll and Signal/SignalAll thread is not scheduled due to priorities, affinity or other scheduler artifacts. This could lead to stalls of up to tens of seconds in some cases. PiperOrigin-RevId: 449159670 Change-Id: I64bbd277c1f91964cfba3306ba8a80eeadf85f64
* Add a stress test for base_internal::ThreadIdentity reuse.Gravatar Abseil Team2022-05-16
| | | | | PiperOrigin-RevId: 449067700 Change-Id: I972b1736c28d76ed500e9ad6fd15c7a469a5825f
* Fix spelling error "charachter"Gravatar Abseil Team2022-05-11
| | | | | PiperOrigin-RevId: 448159349 Change-Id: I6b25a90d8a3b6d3a888274d156aa696d77fb042d
* Fix typo: "a the condition" -> "a condition".Gravatar Abseil Team2022-04-22
| | | | | PiperOrigin-RevId: 443723710 Change-Id: Ic39b0cf2b289efa9cd9434616949dd08a1a35117
* Export of internal Abseil changesGravatar Abseil Team2022-04-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | -- f4c7e510922668c68be4aa79a00867c3d3ca9f95 by Derek Mauro <dmauro@google.com>: Many improvements to LeakChecker builds The presence of the LeakChecker is now detected when possible. GCC users using LeakChecker in standalone mode still need to use -DLEAK_CHECKER. This is now documented in the header. The hacky targets used for testing leak checking have been removed in favor of testing in AddressSanitizer mode on Kokoro. Fixes #885 Fixes #1153 PiperOrigin-RevId: 441203393 Change-Id: Ibe64ef6b104bcaf31839ff7184e558cc86abdd1c -- 5c70a23aa83b8152ab95d2cf21662fc63c80ef7d by Abseil Team <absl-team@google.com>: Add a benchmark for stacktrace PiperOrigin-RevId: 441196473 Change-Id: I4c9aa2e797aa2cae09abfaaee3abe5c09eb62fc4 -- 50b406052273b9d5bad04a7860a96e4d5d956c02 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 441114481 Change-Id: I667af7a50d5631ca91289dd24c91ba90233e0184 -- 568b4eaac120b420bce5290179d407d2b57d5bae by Dino Radakovic <dinor@google.com>: Internal change PiperOrigin-RevId: 440894155 Change-Id: Ia587ffc65a8321126585fb363b7c0ca8cc2a0da2 -- d53948eace4f3a10ac5a6c1496dc51b81adc412c by Abseil Team <absl-team@google.com>: Explicitly give internal linkage to symbols which are not used outside of their translation units. PiperOrigin-RevId: 440424519 Change-Id: I531c5e229d443375483b7550a34f48042589a99b GitOrigin-RevId: f4c7e510922668c68be4aa79a00867c3d3ca9f95
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