Messages in this thread Patch in this message | | | Date | Fri, 3 Nov 2006 21:46:11 +0200 | From | Guillem Jover <> | Subject | [PATCH] Allowing user processes to rise their oom_adj value |
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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 <guillem.jover@nokia.com> --- fs/proc/base.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c index 8df2740..955bb0a 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -682,8 +682,6 @@ 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; @@ -698,6 +696,10 @@ 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) -- 1.4.3.3 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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