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| author | Oleg Nesterov <oleg@redhat.com> | 2014-12-10 15:55:08 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-10 17:41:17 -0800 |
| commit | 175aed3f8d38b87d3287bb765c794205f2b511de (patch) | |
| tree | 81365f68bb26d9c14cc6059990ca0deb6b6af941 /kernel/exit.c | |
| parent | 3750ef979cfa1296630aa9f23e265c1bd721498a (diff) | |
| download | linux-stable-175aed3f8d38b87d3287bb765c794205f2b511de.tar.gz linux-stable-175aed3f8d38b87d3287bb765c794205f2b511de.tar.bz2 linux-stable-175aed3f8d38b87d3287bb765c794205f2b511de.zip | |
exit: reparent: document the ->has_child_subreaper checks
Swap the "init_task" and same_thread_group() checks. This way it is more
simple to document these checks and we can remove the link to the previous
discussion on lkml.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Sterling Alexander <stalexan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index a4204aaba8a2..576949ce5665 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -495,18 +495,16 @@ static struct task_struct *find_new_reaper(struct task_struct *father) if (father->signal->has_child_subreaper) { struct task_struct *reaper; - /* - * Find the first ancestor marked as child_subreaper. - * Note that the code below checks same_thread_group(reaper, - * pid_ns->child_reaper). This is what we need to DTRT in a - * PID namespace. However we still need the check above, see - * http://marc.info/?l=linux-kernel&m=131385460420380 + * Find the first ->is_child_subreaper ancestor in our pid_ns. + * We start from father to ensure we can not look into another + * namespace, this is safe because all its threads are dead. */ for (reaper = father; - reaper != &init_task; + !same_thread_group(reaper, pid_ns->child_reaper); reaper = reaper->real_parent) { - if (same_thread_group(reaper, pid_ns->child_reaper)) + /* call_usermodehelper() descendants need this check */ + if (reaper == &init_task) break; if (!reaper->signal->is_child_subreaper) continue; |