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| author | Pavel Emelyanov <xemul@parallels.com> | 2012-01-13 02:20:27 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-13 05:13:11 +0100 |
| commit | b8f566b04d3cddd192cfd2418ae6d54ac6353792 (patch) | |
| tree | 32a5bf86548cd43feff4822d800b6a99e157b5d7 /kernel/pid.c | |
| parent | kdump: add udev events for memory online/offline (diff) | |
| download | linux-b8f566b04d3cddd192cfd2418ae6d54ac6353792.tar.xz linux-b8f566b04d3cddd192cfd2418ae6d54ac6353792.zip | |
sysctl: add the kernel.ns_last_pid control
The sysctl works on the current task's pid namespace, getting and setting
its last_pid field.
Writing is allowed for CAP_SYS_ADMIN-capable tasks thus making it possible
to create a task with desired pid value. This ability is required badly
for the checkpoint/restore in userspace.
This approach suits all the parties for now.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/pid.c')
| -rw-r--r-- | kernel/pid.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/pid.c b/kernel/pid.c index fa5f72227e5f..ce8e00deaccb 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -137,7 +137,9 @@ static int pid_before(int base, int a, int b) } /* - * We might be racing with someone else trying to set pid_ns->last_pid. + * We might be racing with someone else trying to set pid_ns->last_pid + * at the pid allocation time (there's also a sysctl for this, but racing + * with this one is OK, see comment in kernel/pid_namespace.c about it). * We want the winner to have the "later" value, because if the * "earlier" value prevails, then a pid may get reused immediately. * |