path: root/kernel/sys.c
diff options
authorAmnon Shiloh <>2013-04-30 15:28:48 -0700
committerLinus Torvalds <>2013-04-30 17:04:09 -0700
commit52b3694157e3aa6df871e283115652ec6f2d31e0 (patch)
tree80b1c1d6a1ddce73ba722375a44143fa318aa50c /kernel/sys.c
parent22145aa1f65c2bb4a008bc29054349a4a6c4f565 (diff)
kernel/sys.c: make prctl(PR_SET_MM) generally available
The purpose of this patch is to allow privileged processes to set their own per-memory memory-region fields: start_code, end_code, start_data, end_data, start_brk, brk, start_stack, arg_start, arg_end, env_start, env_end. This functionality is needed by any application or package that needs to reconstruct Linux processes, that is, to start them in any way other than by means of an "execve()" from an executable file. This includes: 1. Restoring processes from a checkpoint-file (by all potential user-level checkpointing packages, not only CRIU's). 2. Restarting processes on another node after process migration. 3. Starting duplicated copies of a running process (for reliability and high-availablity). 4. Starting a process from an executable format that is not supported by Linux, thus requiring a "manual execve" by a user-level utility. 5. Similarly, starting a process from a networked and/or crypted executable that, for confidentiality, licensing or other reasons, may not be written to the local file-systems. The code that does that was already included in the Linux kernel by the CRIU group, in the form of "prctl(PR_SET_MM)", but prior to this was enclosed within their private "#ifdef CONFIG_CHECKPOINT_RESTORE", which is normally disabled. The patch removes those ifdefs. Signed-off-by: Amnon Shiloh <> Cc: Cyrill Gorcunov <> Cc: Pavel Emelyanov <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'kernel/sys.c')
1 files changed, 2 insertions, 8 deletions
diff --git a/kernel/sys.c b/kernel/sys.c
index e30eba430b96..afd0f7e125c9 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1857,7 +1857,6 @@ SYSCALL_DEFINE1(umask, int, mask)
return mask;
static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
struct fd exe;
@@ -2051,17 +2050,12 @@ out:
return error;
static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
return put_user(me->clear_child_tid, tid_addr);
-static int prctl_set_mm(int opt, unsigned long addr,
- unsigned long arg4, unsigned long arg5)
- return -EINVAL;
static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
return -EINVAL;