4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann <arnd@xxxxxxxx> commit 4c1baad223906943b595a887305f2e8124821dad upstream. Running the compaction_test sometimes results in out-of-memory failures. When I debugged this, it turned out that the code to reset the number of hugepages to the initial value is simply broken since we write into an open sysctl file descriptor multiple times without seeking back to the start. Adding the lseek here fixes the problem. Cc: stable@xxxxxxxxxxxxxxx Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> Link: https://bugs.linaro.org/show_bug.cgi?id=3145 Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/vm/compaction_test.c | 2 ++ 1 file changed, 2 insertions(+) --- a/tools/testing/selftests/vm/compaction_test.c +++ b/tools/testing/selftests/vm/compaction_test.c @@ -136,6 +136,8 @@ int check_compaction(unsigned long mem_f printf("No of huge pages allocated = %d\n", (atoi(nr_hugepages))); + lseek(fd, 0, SEEK_SET); + if (write(fd, initial_nr_hugepages, strlen(initial_nr_hugepages)) != strlen(initial_nr_hugepages)) { perror("Failed to write value to /proc/sys/vm/nr_hugepages\n");