The patch titled Subject: selftest/vm: verify mmap addr in mremap_test has been added to the -mm tree. Its filename is selftest-vm-verify-mmap-addr-in-mremap_test.patch
This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/selftest-vm-verify-mmap-addr-in-mr... and later at https://ozlabs.org/~akpm/mmotm/broken-out/selftest-vm-verify-mmap-addr-in-mr...
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------------------------------------------------------ From: Sidhartha Kumar sidhartha.kumar@oracle.com Subject: selftest/vm: verify mmap addr in mremap_test
Patch series "selftest/vm fix segfault in mremap_test".
Avoid calling mmap with requested addresses that are less than the system's mmap_min_addr. Running the test as root returns EACCES when trying to map addresses < mmap_min_addr which is not one of the error codes for the retry condition. Add a munmap call after an alignment check as the mappings are retained after the retry and can reach vm.max_map_count.
Link: https://lkml.kernel.org/r/20220414171529.62058-1-sidhartha.kumar@oracle.com Link: https://lkml.kernel.org/r/20220414171529.62058-2-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar sidhartha.kumar@oracle.com Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
--- a/tools/testing/selftests/vm/mremap_test.c~selftest-vm-verify-mmap-addr-in-mremap_test +++ a/tools/testing/selftests/vm/mremap_test.c @@ -6,6 +6,7 @@
#include <errno.h> #include <stdlib.h> +#include <stdio.h> #include <string.h> #include <sys/mman.h> #include <time.h> @@ -63,6 +64,35 @@ enum { .expect_failure = should_fail \ }
+/* Returns mmap_min_addr sysctl */ +static unsigned long long get_mmap_min_addr(void) +{ + FILE *fp; + int n_matched; + static unsigned long long addr; + + if (addr) + return addr; + + fp = fopen("/proc/sys/vm/mmap_min_addr", "r"); + if (fp == NULL) { + ksft_print_msg("Failed to open /proc/sys/vm/mmap_min_addr: %s\n", + strerror(errno)); + exit(KSFT_SKIP); + } + + n_matched = fscanf(fp, "%llu", &addr); + if (n_matched != 1) { + ksft_print_msg("Failed to read /proc/sys/vm/mmap_min_addr: %s\n", + strerror(errno)); + fclose(fp); + exit(KSFT_SKIP); + } + + fclose(fp); + return addr; +} + /* * Returns the start address of the mapping on success, else returns * NULL on failure. @@ -71,8 +101,15 @@ static void *get_source_mapping(struct c { unsigned long long addr = 0ULL; void *src_addr = NULL; + unsigned long long mmap_min_addr; + + mmap_min_addr = get_mmap_min_addr(); + retry: addr += c.src_alignment; + if (addr < mmap_min_addr) + goto retry; + src_addr = mmap((void *) addr, c.region_size, PROT_READ | PROT_WRITE, MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED, -1, 0); @@ -90,8 +127,10 @@ retry: * alignment in the tests. */ if (((unsigned long long) src_addr & (c.src_alignment - 1)) || - !((unsigned long long) src_addr & c.src_alignment)) + !((unsigned long long) src_addr & c.src_alignment)) { + munmap(src_addr, c.region_size); goto retry; + }
if (!src_addr) goto error; _
Patches currently in -mm which might be from sidhartha.kumar@oracle.com are
selftest-vm-verify-mmap-addr-in-mremap_test.patch selftest-vm-verify-remap-destination-address-in-mremap_test.patch selftest-vm-support-xfail-in-mremap_test.patch selftest-vm-add-skip-support-to-mremap_test.patch selftest-vm-clarify-error-statement-in-gup_test.patch