| Message ID | 20181013133929.28653-1-mpe@ellerman.id.au (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | selftests/vm: Add a test for MAP_FIXED_NOREPLACE | expand |
On Sat, Oct 13, 2018 at 6:39 AM, Michael Ellerman <mpe@ellerman.id.au> wrote: > Add a test for MAP_FIXED_NOREPLACE, based on some code originally by > Jann Horn. This would have caught the overlap bug reported by Daniel Micay. > > I originally suggested to Michal that we create MAP_FIXED_NOREPLACE, but > instead of writing a selftest I spent my time bike-shedding whether it > should be called MAP_FIXED_SAFE/NOCLOBBER/WEAK/NEW .. mea culpa. LOL. :) Reviewed-by: Kees Cook <keescook@chromium.org> -Kees > > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > --- > tools/testing/selftests/vm/.gitignore | 1 + > tools/testing/selftests/vm/Makefile | 1 + > .../selftests/vm/map_fixed_noreplace.c | 206 ++++++++++++++++++ > 3 files changed, 208 insertions(+) > create mode 100644 tools/testing/selftests/vm/map_fixed_noreplace.c > > diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore > index af5ff83f6d7f..31b3c98b6d34 100644 > --- a/tools/testing/selftests/vm/.gitignore > +++ b/tools/testing/selftests/vm/.gitignore > @@ -13,3 +13,4 @@ mlock-random-test > virtual_address_range > gup_benchmark > va_128TBswitch > +map_fixed_noreplace > diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile > index e94b7b14bcb2..6e67e726e5a5 100644 > --- a/tools/testing/selftests/vm/Makefile > +++ b/tools/testing/selftests/vm/Makefile > @@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark > TEST_GEN_FILES += hugepage-mmap > TEST_GEN_FILES += hugepage-shm > TEST_GEN_FILES += map_hugetlb > +TEST_GEN_FILES += map_fixed_noreplace > TEST_GEN_FILES += map_populate > TEST_GEN_FILES += mlock-random-test > TEST_GEN_FILES += mlock2-tests > diff --git a/tools/testing/selftests/vm/map_fixed_noreplace.c b/tools/testing/selftests/vm/map_fixed_noreplace.c > new file mode 100644 > index 000000000000..d91bde511268 > --- /dev/null > +++ b/tools/testing/selftests/vm/map_fixed_noreplace.c > @@ -0,0 +1,206 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +/* > + * Test that MAP_FIXED_NOREPLACE works. > + * > + * Copyright 2018, Jann Horn <jannh@google.com> > + * Copyright 2018, Michael Ellerman, IBM Corporation. > + */ > + > +#include <sys/mman.h> > +#include <errno.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <unistd.h> > + > +#ifndef MAP_FIXED_NOREPLACE > +#define MAP_FIXED_NOREPLACE 0x100000 > +#endif > + > +#define BASE_ADDRESS (256ul * 1024 * 1024) > + > + > +static void dump_maps(void) > +{ > + char cmd[32]; > + > + snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid()); > + system(cmd); > +} > + > +int main(void) > +{ > + unsigned long flags, addr, size, page_size; > + char *p; > + > + page_size = sysconf(_SC_PAGE_SIZE); > + > + flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE; > + > + // Check we can map all the areas we need below > + errno = 0; > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error: couldn't map the space we need for the test\n"); > + return 1; > + } > + > + errno = 0; > + if (munmap((void *)addr, 5 * page_size) != 0) { > + dump_maps(); > + printf("Error: munmap failed!?\n"); > + return 1; > + } > + printf("unmap() successful\n"); > + > + errno = 0; > + addr = BASE_ADDRESS + page_size; > + size = 3 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error: first mmap() failed unexpectedly\n"); > + return 1; > + } > + > + /* > + * Exact same mapping again: > + * base | free | new > + * +1 | mapped | new > + * +2 | mapped | new > + * +3 | mapped | new > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:1: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Second mapping contained within first: > + * > + * base | free | > + * +1 | mapped | > + * +2 | mapped | new > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS + (2 * page_size); > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:2: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Overlap end of existing mapping: > + * base | free | > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | new > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS + (3 * page_size); > + size = 2 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:3: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Overlap start of existing mapping: > + * base | free | new > + * +1 | mapped | new > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = 2 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:4: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Adjacent to start of existing mapping: > + * base | free | new > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error:5: mmap() failed when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Adjacent to end of existing mapping: > + * base | free | > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS + (4 * page_size); > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error:6: mmap() failed when it shouldn't have\n"); > + return 1; > + } > + > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + if (munmap((void *)addr, size) != 0) { > + dump_maps(); > + printf("Error: munmap failed!?\n"); > + return 1; > + } > + printf("unmap() successful\n"); > + > + printf("OK\n"); > + return 0; > +} > -- > 2.17.1 >
On 10/13/2018 07:39 AM, Michael Ellerman wrote: > Add a test for MAP_FIXED_NOREPLACE, based on some code originally by > Jann Horn. This would have caught the overlap bug reported by Daniel Micay. > > I originally suggested to Michal that we create MAP_FIXED_NOREPLACE, but > instead of writing a selftest I spent my time bike-shedding whether it > should be called MAP_FIXED_SAFE/NOCLOBBER/WEAK/NEW .. mea culpa. > > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > --- Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> -- Khalid > tools/testing/selftests/vm/.gitignore | 1 + > tools/testing/selftests/vm/Makefile | 1 + > .../selftests/vm/map_fixed_noreplace.c | 206 ++++++++++++++++++ > 3 files changed, 208 insertions(+) > create mode 100644 tools/testing/selftests/vm/map_fixed_noreplace.c > > diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore > index af5ff83f6d7f..31b3c98b6d34 100644 > --- a/tools/testing/selftests/vm/.gitignore > +++ b/tools/testing/selftests/vm/.gitignore > @@ -13,3 +13,4 @@ mlock-random-test > virtual_address_range > gup_benchmark > va_128TBswitch > +map_fixed_noreplace > diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile > index e94b7b14bcb2..6e67e726e5a5 100644 > --- a/tools/testing/selftests/vm/Makefile > +++ b/tools/testing/selftests/vm/Makefile > @@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark > TEST_GEN_FILES += hugepage-mmap > TEST_GEN_FILES += hugepage-shm > TEST_GEN_FILES += map_hugetlb > +TEST_GEN_FILES += map_fixed_noreplace > TEST_GEN_FILES += map_populate > TEST_GEN_FILES += mlock-random-test > TEST_GEN_FILES += mlock2-tests > diff --git a/tools/testing/selftests/vm/map_fixed_noreplace.c b/tools/testing/selftests/vm/map_fixed_noreplace.c > new file mode 100644 > index 000000000000..d91bde511268 > --- /dev/null > +++ b/tools/testing/selftests/vm/map_fixed_noreplace.c > @@ -0,0 +1,206 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +/* > + * Test that MAP_FIXED_NOREPLACE works. > + * > + * Copyright 2018, Jann Horn <jannh@google.com> > + * Copyright 2018, Michael Ellerman, IBM Corporation. > + */ > + > +#include <sys/mman.h> > +#include <errno.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <unistd.h> > + > +#ifndef MAP_FIXED_NOREPLACE > +#define MAP_FIXED_NOREPLACE 0x100000 > +#endif > + > +#define BASE_ADDRESS (256ul * 1024 * 1024) > + > + > +static void dump_maps(void) > +{ > + char cmd[32]; > + > + snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid()); > + system(cmd); > +} > + > +int main(void) > +{ > + unsigned long flags, addr, size, page_size; > + char *p; > + > + page_size = sysconf(_SC_PAGE_SIZE); > + > + flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE; > + > + // Check we can map all the areas we need below > + errno = 0; > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error: couldn't map the space we need for the test\n"); > + return 1; > + } > + > + errno = 0; > + if (munmap((void *)addr, 5 * page_size) != 0) { > + dump_maps(); > + printf("Error: munmap failed!?\n"); > + return 1; > + } > + printf("unmap() successful\n"); > + > + errno = 0; > + addr = BASE_ADDRESS + page_size; > + size = 3 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error: first mmap() failed unexpectedly\n"); > + return 1; > + } > + > + /* > + * Exact same mapping again: > + * base | free | new > + * +1 | mapped | new > + * +2 | mapped | new > + * +3 | mapped | new > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:1: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Second mapping contained within first: > + * > + * base | free | > + * +1 | mapped | > + * +2 | mapped | new > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS + (2 * page_size); > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:2: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Overlap end of existing mapping: > + * base | free | > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | new > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS + (3 * page_size); > + size = 2 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:3: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Overlap start of existing mapping: > + * base | free | new > + * +1 | mapped | new > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = 2 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:4: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Adjacent to start of existing mapping: > + * base | free | new > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error:5: mmap() failed when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Adjacent to end of existing mapping: > + * base | free | > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS + (4 * page_size); > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error:6: mmap() failed when it shouldn't have\n"); > + return 1; > + } > + > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + if (munmap((void *)addr, size) != 0) { > + dump_maps(); > + printf("Error: munmap failed!?\n"); > + return 1; > + } > + printf("unmap() successful\n"); > + > + printf("OK\n"); > + return 0; > +} >
On Sun 14-10-18 00:39:29, Michael Ellerman wrote: > Add a test for MAP_FIXED_NOREPLACE, based on some code originally by > Jann Horn. This would have caught the overlap bug reported by Daniel Micay. > > I originally suggested to Michal that we create MAP_FIXED_NOREPLACE, but > instead of writing a selftest I spent my time bike-shedding whether it > should be called MAP_FIXED_SAFE/NOCLOBBER/WEAK/NEW .. mea culpa. You wer one of those to provide a useful feedback actually. So no reason to feel sorry. I should have been forced to write a test case instead. No idea why I haven't considered that myself actually. So I steal your culpa here. > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Thanks for doing this! Acked-by: Michal Hocko <mhocko@suse.com> > --- > tools/testing/selftests/vm/.gitignore | 1 + > tools/testing/selftests/vm/Makefile | 1 + > .../selftests/vm/map_fixed_noreplace.c | 206 ++++++++++++++++++ > 3 files changed, 208 insertions(+) > create mode 100644 tools/testing/selftests/vm/map_fixed_noreplace.c > > diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore > index af5ff83f6d7f..31b3c98b6d34 100644 > --- a/tools/testing/selftests/vm/.gitignore > +++ b/tools/testing/selftests/vm/.gitignore > @@ -13,3 +13,4 @@ mlock-random-test > virtual_address_range > gup_benchmark > va_128TBswitch > +map_fixed_noreplace > diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile > index e94b7b14bcb2..6e67e726e5a5 100644 > --- a/tools/testing/selftests/vm/Makefile > +++ b/tools/testing/selftests/vm/Makefile > @@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark > TEST_GEN_FILES += hugepage-mmap > TEST_GEN_FILES += hugepage-shm > TEST_GEN_FILES += map_hugetlb > +TEST_GEN_FILES += map_fixed_noreplace > TEST_GEN_FILES += map_populate > TEST_GEN_FILES += mlock-random-test > TEST_GEN_FILES += mlock2-tests > diff --git a/tools/testing/selftests/vm/map_fixed_noreplace.c b/tools/testing/selftests/vm/map_fixed_noreplace.c > new file mode 100644 > index 000000000000..d91bde511268 > --- /dev/null > +++ b/tools/testing/selftests/vm/map_fixed_noreplace.c > @@ -0,0 +1,206 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +/* > + * Test that MAP_FIXED_NOREPLACE works. > + * > + * Copyright 2018, Jann Horn <jannh@google.com> > + * Copyright 2018, Michael Ellerman, IBM Corporation. > + */ > + > +#include <sys/mman.h> > +#include <errno.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <unistd.h> > + > +#ifndef MAP_FIXED_NOREPLACE > +#define MAP_FIXED_NOREPLACE 0x100000 > +#endif > + > +#define BASE_ADDRESS (256ul * 1024 * 1024) > + > + > +static void dump_maps(void) > +{ > + char cmd[32]; > + > + snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid()); > + system(cmd); > +} > + > +int main(void) > +{ > + unsigned long flags, addr, size, page_size; > + char *p; > + > + page_size = sysconf(_SC_PAGE_SIZE); > + > + flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE; > + > + // Check we can map all the areas we need below > + errno = 0; > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error: couldn't map the space we need for the test\n"); > + return 1; > + } > + > + errno = 0; > + if (munmap((void *)addr, 5 * page_size) != 0) { > + dump_maps(); > + printf("Error: munmap failed!?\n"); > + return 1; > + } > + printf("unmap() successful\n"); > + > + errno = 0; > + addr = BASE_ADDRESS + page_size; > + size = 3 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error: first mmap() failed unexpectedly\n"); > + return 1; > + } > + > + /* > + * Exact same mapping again: > + * base | free | new > + * +1 | mapped | new > + * +2 | mapped | new > + * +3 | mapped | new > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:1: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Second mapping contained within first: > + * > + * base | free | > + * +1 | mapped | > + * +2 | mapped | new > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS + (2 * page_size); > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:2: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Overlap end of existing mapping: > + * base | free | > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | new > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS + (3 * page_size); > + size = 2 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:3: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Overlap start of existing mapping: > + * base | free | new > + * +1 | mapped | new > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = 2 * page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p != MAP_FAILED) { > + dump_maps(); > + printf("Error:4: mmap() succeeded when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Adjacent to start of existing mapping: > + * base | free | new > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | > + */ > + errno = 0; > + addr = BASE_ADDRESS; > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error:5: mmap() failed when it shouldn't have\n"); > + return 1; > + } > + > + /* > + * Adjacent to end of existing mapping: > + * base | free | > + * +1 | mapped | > + * +2 | mapped | > + * +3 | mapped | > + * +4 | free | new > + */ > + errno = 0; > + addr = BASE_ADDRESS + (4 * page_size); > + size = page_size; > + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); > + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); > + > + if (p == MAP_FAILED) { > + dump_maps(); > + printf("Error:6: mmap() failed when it shouldn't have\n"); > + return 1; > + } > + > + addr = BASE_ADDRESS; > + size = 5 * page_size; > + if (munmap((void *)addr, size) != 0) { > + dump_maps(); > + printf("Error: munmap failed!?\n"); > + return 1; > + } > + printf("unmap() successful\n"); > + > + printf("OK\n"); > + return 0; > +} > -- > 2.17.1 >
Michal Hocko <mhocko@kernel.org> writes: > On Sun 14-10-18 00:39:29, Michael Ellerman wrote: >> Add a test for MAP_FIXED_NOREPLACE, based on some code originally by >> Jann Horn. This would have caught the overlap bug reported by Daniel Micay. >> >> I originally suggested to Michal that we create MAP_FIXED_NOREPLACE, but >> instead of writing a selftest I spent my time bike-shedding whether it >> should be called MAP_FIXED_SAFE/NOCLOBBER/WEAK/NEW .. mea culpa. > > You wer one of those to provide a useful feedback actually. So no reason > to feel sorry. I should have been forced to write a test case instead. > No idea why I haven't considered that myself actually. So I steal your > culpa here. Haha, plenty of culpa to go around :) Yeah we should try to always have selftests for new flags and things like this. This one was a bit special because the original point of the new flag was for the kernel to use internally, and we sort of forgot that we were also adding a user-visible flag. >> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > > Thanks for doing this! > Acked-by: Michal Hocko <mhocko@suse.com> Thanks. cheers
diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore index af5ff83f6d7f..31b3c98b6d34 100644 --- a/tools/testing/selftests/vm/.gitignore +++ b/tools/testing/selftests/vm/.gitignore @@ -13,3 +13,4 @@ mlock-random-test virtual_address_range gup_benchmark va_128TBswitch +map_fixed_noreplace diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index e94b7b14bcb2..6e67e726e5a5 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark TEST_GEN_FILES += hugepage-mmap TEST_GEN_FILES += hugepage-shm TEST_GEN_FILES += map_hugetlb +TEST_GEN_FILES += map_fixed_noreplace TEST_GEN_FILES += map_populate TEST_GEN_FILES += mlock-random-test TEST_GEN_FILES += mlock2-tests diff --git a/tools/testing/selftests/vm/map_fixed_noreplace.c b/tools/testing/selftests/vm/map_fixed_noreplace.c new file mode 100644 index 000000000000..d91bde511268 --- /dev/null +++ b/tools/testing/selftests/vm/map_fixed_noreplace.c @@ -0,0 +1,206 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Test that MAP_FIXED_NOREPLACE works. + * + * Copyright 2018, Jann Horn <jannh@google.com> + * Copyright 2018, Michael Ellerman, IBM Corporation. + */ + +#include <sys/mman.h> +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> + +#ifndef MAP_FIXED_NOREPLACE +#define MAP_FIXED_NOREPLACE 0x100000 +#endif + +#define BASE_ADDRESS (256ul * 1024 * 1024) + + +static void dump_maps(void) +{ + char cmd[32]; + + snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid()); + system(cmd); +} + +int main(void) +{ + unsigned long flags, addr, size, page_size; + char *p; + + page_size = sysconf(_SC_PAGE_SIZE); + + flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE; + + // Check we can map all the areas we need below + errno = 0; + addr = BASE_ADDRESS; + size = 5 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p == MAP_FAILED) { + dump_maps(); + printf("Error: couldn't map the space we need for the test\n"); + return 1; + } + + errno = 0; + if (munmap((void *)addr, 5 * page_size) != 0) { + dump_maps(); + printf("Error: munmap failed!?\n"); + return 1; + } + printf("unmap() successful\n"); + + errno = 0; + addr = BASE_ADDRESS + page_size; + size = 3 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p == MAP_FAILED) { + dump_maps(); + printf("Error: first mmap() failed unexpectedly\n"); + return 1; + } + + /* + * Exact same mapping again: + * base | free | new + * +1 | mapped | new + * +2 | mapped | new + * +3 | mapped | new + * +4 | free | new + */ + errno = 0; + addr = BASE_ADDRESS; + size = 5 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p != MAP_FAILED) { + dump_maps(); + printf("Error:1: mmap() succeeded when it shouldn't have\n"); + return 1; + } + + /* + * Second mapping contained within first: + * + * base | free | + * +1 | mapped | + * +2 | mapped | new + * +3 | mapped | + * +4 | free | + */ + errno = 0; + addr = BASE_ADDRESS + (2 * page_size); + size = page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p != MAP_FAILED) { + dump_maps(); + printf("Error:2: mmap() succeeded when it shouldn't have\n"); + return 1; + } + + /* + * Overlap end of existing mapping: + * base | free | + * +1 | mapped | + * +2 | mapped | + * +3 | mapped | new + * +4 | free | new + */ + errno = 0; + addr = BASE_ADDRESS + (3 * page_size); + size = 2 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p != MAP_FAILED) { + dump_maps(); + printf("Error:3: mmap() succeeded when it shouldn't have\n"); + return 1; + } + + /* + * Overlap start of existing mapping: + * base | free | new + * +1 | mapped | new + * +2 | mapped | + * +3 | mapped | + * +4 | free | + */ + errno = 0; + addr = BASE_ADDRESS; + size = 2 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p != MAP_FAILED) { + dump_maps(); + printf("Error:4: mmap() succeeded when it shouldn't have\n"); + return 1; + } + + /* + * Adjacent to start of existing mapping: + * base | free | new + * +1 | mapped | + * +2 | mapped | + * +3 | mapped | + * +4 | free | + */ + errno = 0; + addr = BASE_ADDRESS; + size = page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p == MAP_FAILED) { + dump_maps(); + printf("Error:5: mmap() failed when it shouldn't have\n"); + return 1; + } + + /* + * Adjacent to end of existing mapping: + * base | free | + * +1 | mapped | + * +2 | mapped | + * +3 | mapped | + * +4 | free | new + */ + errno = 0; + addr = BASE_ADDRESS + (4 * page_size); + size = page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p == MAP_FAILED) { + dump_maps(); + printf("Error:6: mmap() failed when it shouldn't have\n"); + return 1; + } + + addr = BASE_ADDRESS; + size = 5 * page_size; + if (munmap((void *)addr, size) != 0) { + dump_maps(); + printf("Error: munmap failed!?\n"); + return 1; + } + printf("unmap() successful\n"); + + printf("OK\n"); + return 0; +}
Add a test for MAP_FIXED_NOREPLACE, based on some code originally by Jann Horn. This would have caught the overlap bug reported by Daniel Micay. I originally suggested to Michal that we create MAP_FIXED_NOREPLACE, but instead of writing a selftest I spent my time bike-shedding whether it should be called MAP_FIXED_SAFE/NOCLOBBER/WEAK/NEW .. mea culpa. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 1 + .../selftests/vm/map_fixed_noreplace.c | 206 ++++++++++++++++++ 3 files changed, 208 insertions(+) create mode 100644 tools/testing/selftests/vm/map_fixed_noreplace.c