From: Guillem Jover Currently a user process cannot rise its own oom_adj value (i.e. unprotecting itself from the OOM killer). As this value is stored in the task structure it gets inherited and the unprivileged childs will be unable to rise it. The EPERM will be handled by the generic proc fs layer, as only processes with the proper caps or the owner of the process will be able to write to the file. So we allow only the processes with CAP_SYS_RESOURCE to lower the value, otherwise it will get an EACCES which seems more appropriate than EPERM. Signed-off-by: Guillem Jover Acked-by: Andrea Arcangeli Signed-off-by: Andrew Morton --- fs/proc/base.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff -puN fs/proc/base.c~allowing-user-processes-to-rise-their-oom_adj-value fs/proc/base.c --- a/fs/proc/base.c~allowing-user-processes-to-rise-their-oom_adj-value +++ a/fs/proc/base.c @@ -681,8 +681,6 @@ static ssize_t oom_adjust_write(struct f char buffer[PROC_NUMBUF], *end; int oom_adjust; - if (!capable(CAP_SYS_RESOURCE)) - return -EPERM; memset(buffer, 0, sizeof(buffer)); if (count > sizeof(buffer) - 1) count = sizeof(buffer) - 1; @@ -697,6 +695,10 @@ static ssize_t oom_adjust_write(struct f task = get_proc_task(file->f_dentry->d_inode); if (!task) return -ESRCH; + if (oom_adjust < task->oomkilladj && !capable(CAP_SYS_RESOURCE)) { + put_task_struct(task); + return -EACCES; + } task->oomkilladj = oom_adjust; put_task_struct(task); if (end - buffer == 0) _