/* * 32-bit test to check vDSO mremap. * * Copyright (c) 2016 Dmitry Safonov * Suggested-by: Andrew Lutomirski * * This program is free software; you can redistribute it and/or modify * it under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ /* * Can be built statically: * gcc -Os -Wall -static -m32 test_mremap_vdso.c */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #define PAGE_SIZE 4096 static int try_to_remap(void *vdso_addr, unsigned long size) { void *dest_addr, *new_addr; /* Searching for memory location where to remap */ dest_addr = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); if (dest_addr == MAP_FAILED) { printf("[WARN]\tmmap failed (%d): %m\n", errno); return 0; } printf("[NOTE]\tMoving vDSO: [%p, %#lx] -> [%p, %#lx]\n", vdso_addr, (unsigned long)vdso_addr + size, dest_addr, (unsigned long)dest_addr + size); fflush(stdout); new_addr = mremap(vdso_addr, size, size, MREMAP_FIXED|MREMAP_MAYMOVE, dest_addr); if ((unsigned long)new_addr == (unsigned long)-1) { munmap(dest_addr, size); if (errno == EINVAL) { printf("[NOTE]\tvDSO partial move failed, will try with bigger size\n"); return -1; /* Retry with larger */ } printf("[FAIL]\tmremap failed (%d): %m\n", errno); return 1; } return 0; } int main(int argc, char **argv, char **envp) { pid_t child; child = fork(); if (child == -1) { printf("[WARN]\tfailed to fork (%d): %m\n", errno); return 1; } if (child == 0) { unsigned long vdso_size = PAGE_SIZE; unsigned long auxval; int ret = -1; auxval = getauxval(AT_SYSINFO_EHDR); printf("\tAT_SYSINFO_EHDR is %#lx\n", auxval); if (!auxval || auxval == -ENOENT) { printf("[WARN]\tgetauxval failed\n"); return 0; } /* Simpler than parsing ELF header */ while (ret < 0) { ret = try_to_remap((void *)auxval, vdso_size); vdso_size += PAGE_SIZE; } /* Glibc is likely to explode now - exit with raw syscall */ asm volatile ("int $0x80" : : "a" (__NR_exit), "b" (!!ret)); } else { int status; if (waitpid(child, &status, 0) != child || !WIFEXITED(status)) { printf("[FAIL]\tmremap() of the vDSO does not work on this kernel!\n"); return 1; } else if (WEXITSTATUS(status) != 0) { printf("[FAIL]\tChild failed with %d\n", WEXITSTATUS(status)); return 1; } printf("[OK]\n"); } return 0; } option value='4'>4space:mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-12 21:58:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-12 21:58:13 -0800
commite7aa8c2eb11ba69b1b69099c3c7bd6be3087b0ba (patch)
treef63906f41699c8e38af9d12b063e2ceab0286ef2 /fs/cifs/fscache.h
parente34bac726d27056081d0250c0e173e4b155aa340 (diff)
parent868c97a846a73e937d835b09b8c885a69df50ec8 (diff)
Merge tag 'docs-4.10' of git://git.lwn.net/linuxHEADmaster
Pull documentation update from Jonathan Corbet: "These are the documentation changes for 4.10. It's another busy cycle for the docs tree, as the sphinx conversion continues. Highlights include: - Further work on PDF output, which remains a bit of a pain but should be more solid now. - Five more DocBook template files converted to Sphinx. Only 27 to go... Lots of plain-text files have also been converted and integrated. - Images in binary formats have been replaced with more source-friendly versions. - Various bits of organizational work, including the renaming of various files discussed at the kernel summit. - New documentation for the device_link mechanism. ... and, of course, lots of typo fixes and small updates" * tag 'docs-4.10' of git://git.lwn.net/linux: (193 commits) dma-buf: Extract dma-buf.rst Update Documentation/00-INDEX docs: 00-INDEX: document directories/files with no docs docs: 00-INDEX: remove non-existing entries docs: 00-INDEX: add missing entries for documentation files/dirs docs: 00-INDEX: consolidate process/ and admin-guide/ description scripts: add a script to check if Documentation/00-INDEX is sane Docs: change sh -> awk in REPORTING-BUGS Documentation/core-api/device_link: Add initial documentation core-api: remove an unexpected unident ppc/idle: Add documentation for powersave=off Doc: Correct typo, "Introdution" => "Introduction" Documentation/atomic_ops.txt: convert to ReST markup Documentation/local_ops.txt: convert to ReST markup Documentation/assoc_array.txt: convert to ReST markup docs-rst: parse-headers.pl: cleanup the documentation docs-rst: fix media cleandocs target docs-rst: media/Makefile: reorganize the rules docs-rst: media: build SVG from graphviz files docs-rst: replace bayer.png by a SVG image ...
Diffstat (limited to 'fs/cifs/fscache.h')