From 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:05:51 +0200 Subject: Adding upstream version 5.10.209. Signed-off-by: Daniel Baumann --- .../powerpc/mm/large_vm_fork_separation.c | 87 ++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 tools/testing/selftests/powerpc/mm/large_vm_fork_separation.c (limited to 'tools/testing/selftests/powerpc/mm/large_vm_fork_separation.c') diff --git a/tools/testing/selftests/powerpc/mm/large_vm_fork_separation.c b/tools/testing/selftests/powerpc/mm/large_vm_fork_separation.c new file mode 100644 index 000000000..2363a7f3a --- /dev/null +++ b/tools/testing/selftests/powerpc/mm/large_vm_fork_separation.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0+ +// +// Copyright 2019, Michael Ellerman, IBM Corp. +// +// Test that allocating memory beyond the memory limit and then forking is +// handled correctly, ie. the child is able to access the mappings beyond the +// memory limit and the child's writes are not visible to the parent. + +#include +#include +#include +#include +#include +#include + +#include "utils.h" + + +#ifndef MAP_FIXED_NOREPLACE +#define MAP_FIXED_NOREPLACE MAP_FIXED // "Should be safe" above 512TB +#endif + + +static int test(void) +{ + int p2c[2], c2p[2], rc, status, c, *p; + unsigned long page_size; + pid_t pid; + + page_size = sysconf(_SC_PAGESIZE); + SKIP_IF(page_size != 65536); + + // Create a mapping at 512TB to allocate an extended_id + p = mmap((void *)(512ul << 40), page_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE, -1, 0); + if (p == MAP_FAILED) { + perror("mmap"); + printf("Error: couldn't mmap(), confirm kernel has 4TB support?\n"); + return 1; + } + + printf("parent writing %p = 1\n", p); + *p = 1; + + FAIL_IF(pipe(p2c) == -1 || pipe(c2p) == -1); + + pid = fork(); + if (pid == 0) { + FAIL_IF(read(p2c[0], &c, 1) != 1); + + pid = getpid(); + printf("child writing %p = %d\n", p, pid); + *p = pid; + + FAIL_IF(write(c2p[1], &c, 1) != 1); + FAIL_IF(read(p2c[0], &c, 1) != 1); + exit(0); + } + + c = 0; + FAIL_IF(write(p2c[1], &c, 1) != 1); + FAIL_IF(read(c2p[0], &c, 1) != 1); + + // Prevent compiler optimisation + barrier(); + + rc = 0; + printf("parent reading %p = %d\n", p, *p); + if (*p != 1) { + printf("Error: BUG! parent saw child's write! *p = %d\n", *p); + rc = 1; + } + + FAIL_IF(write(p2c[1], &c, 1) != 1); + FAIL_IF(waitpid(pid, &status, 0) == -1); + FAIL_IF(!WIFEXITED(status) || WEXITSTATUS(status)); + + if (rc == 0) + printf("success: test completed OK\n"); + + return rc; +} + +int main(void) +{ + return test_harness(test, "large_vm_fork_separation"); +} -- cgit v1.2.3