Author: tstellar Date: Tue Nov 14 11:21:30 2017 New Revision: 318178 URL: http://llvm.org/viewvc/llvm-project?rev=318178&view=rev Log: Merging r317115:
------------------------------------------------------------------------ r317115 | jlpeyton | 2017-11-01 12:44:42 -0700 (Wed, 01 Nov 2017) | 19 lines [OpenMP] Fix race condition in omp_init_lock This is a partial fix for bug 34050. This prevents callers of omp_set_lock (which does not hold __kmp_global_lock) from ever seeing an uninitialized version of __kmp_i_lock_table.table. It does not solve a use-after-free race condition if omp_set_lock obtains a pointer to __kmp_i_lock_table.table before it is updated and then attempts to dereference afterwards. That race is far less likely and can be handled in a separate patch. The unit test usually segfaults on the current trunk revision. It passes with the patch. Patch by Adam Azarchs Differential Revision: https://reviews.llvm.org/D39439 ------------------------------------------------------------------------ Added: openmp/branches/release_50/runtime/test/lock/omp_init_lock.c Modified: openmp/branches/release_50/runtime/src/kmp_lock.cpp Modified: openmp/branches/release_50/runtime/src/kmp_lock.cpp URL: http://llvm.org/viewvc/llvm-project/openmp/branches/release_50/runtime/src/kmp_lock.cpp?rev=318178&r1=318177&r2=318178&view=diff ============================================================================== --- openmp/branches/release_50/runtime/src/kmp_lock.cpp (original) +++ openmp/branches/release_50/runtime/src/kmp_lock.cpp Tue Nov 14 11:21:30 2017 @@ -3061,11 +3061,12 @@ kmp_indirect_lock_t *__kmp_allocate_indi if (idx == __kmp_i_lock_table.size) { // Double up the space for block pointers int row = __kmp_i_lock_table.size / KMP_I_LOCK_CHUNK; - kmp_indirect_lock_t **old_table = __kmp_i_lock_table.table; - __kmp_i_lock_table.table = (kmp_indirect_lock_t **)__kmp_allocate( + kmp_indirect_lock_t **new_table = (kmp_indirect_lock_t **)__kmp_allocate( 2 * row * sizeof(kmp_indirect_lock_t *)); - KMP_MEMCPY(__kmp_i_lock_table.table, old_table, + KMP_MEMCPY(new_table, __kmp_i_lock_table.table, row * sizeof(kmp_indirect_lock_t *)); + kmp_indirect_lock_t **old_table = __kmp_i_lock_table.table; + __kmp_i_lock_table.table = new_table; __kmp_free(old_table); // Allocate new objects in the new blocks for (int i = row; i < 2 * row; ++i) Added: openmp/branches/release_50/runtime/test/lock/omp_init_lock.c URL: http://llvm.org/viewvc/llvm-project/openmp/branches/release_50/runtime/test/lock/omp_init_lock.c?rev=318178&view=auto ============================================================================== --- openmp/branches/release_50/runtime/test/lock/omp_init_lock.c (added) +++ openmp/branches/release_50/runtime/test/lock/omp_init_lock.c Tue Nov 14 11:21:30 2017 @@ -0,0 +1,42 @@ +// RUN: %libomp-compile-and-run +#include "omp_testsuite.h" +#include <stdio.h> + +// This should be slightly less than KMP_I_LOCK_CHUNK, which is 1024 +#define LOCKS_PER_ITER 1000 +#define ITERATIONS (REPETITIONS + 1) + +// This tests concurrently using locks on one thread while initializing new +// ones on another thread. This exercises the global lock pool. +int test_omp_init_lock() { + int i; + omp_lock_t lcks[ITERATIONS * LOCKS_PER_ITER]; +#pragma omp parallel for schedule(static) num_threads(NUM_TASKS) + for (i = 0; i < ITERATIONS; i++) { + int j; + omp_lock_t *my_lcks = &lcks[i * LOCKS_PER_ITER]; + for (j = 0; j < LOCKS_PER_ITER; j++) { + omp_init_lock(&my_lcks[j]); + } + for (j = 0; j < LOCKS_PER_ITER * 100; j++) { + omp_set_lock(&my_lcks[j % LOCKS_PER_ITER]); + omp_unset_lock(&my_lcks[j % LOCKS_PER_ITER]); + } + } + // Wait until all repititions are done. The test is exercising growth of + // the global lock pool, which does not shrink when no locks are allocated. + { + int j; + for (j = 0; j < ITERATIONS * LOCKS_PER_ITER; j++) { + omp_destroy_lock(&lcks[j]); + } + } + + return 0; +} + +int main() { + // No use repeating this test, since it's exercising a private global pool + // which is not reset between test iterations. + return test_omp_init_lock(); +} _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
