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author | Oleg Nesterov <oleg@redhat.com> | 2012-03-19 17:03:22 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-20 14:16:50 -0700 |
commit | e636825346b36a07ccfc8e30946d52855e21f681 (patch) | |
tree | 128c37b3102223a95ce03b856766c33e4d077114 /kernel/signal.c | |
parent | 5f8aadd8b9966d71a77bba52b9d499cc2f38269f (diff) | |
download | linux-e636825346b36a07ccfc8e30946d52855e21f681.tar.bz2 |
exit_signal: simplify the "we have changed execution domain" logic
exit_notify() checks "tsk->self_exec_id != tsk->parent_exec_id"
to handle the "we have changed execution domain" case.
We can change do_thread() to always set ->exit_signal = SIGCHLD
and remove this check to simplify the code.
We could change setup_new_exec() instead, this looks more logical
because it increments ->self_exec_id. But note that de_thread()
already resets ->exit_signal if it changes the leader, let's keep
both changes close to each other.
Note that we change ->exit_signal lockless, this changes the rules.
Thereafter ->exit_signal is not stable under tasklist but this is
fine, the only possible change is OLDSIG -> SIGCHLD. This can race
with eligible_child() but the race is harmless. We can race with
reparent_leader() which changes our ->exit_signal in parallel, but
it does the same change to SIGCHLD.
The noticeable user-visible change is that the execing task is not
"visible" to do_wait()->eligible_child(__WCLONE) right after exec.
To me this looks more logical, and this is consistent with mt case.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/signal.c')
0 files changed, 0 insertions, 0 deletions