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authorEric W. Biederman <ebiederm@xmission.com>2022-06-21 14:38:52 -0500
committerEric W. Biederman <ebiederm@xmission.com>2022-07-20 10:23:51 -0500
commitd80f7d7b2c75c5954d335dffbccca62a5002c3e0 (patch)
tree323d202b5875f926c9b35f660ed3c1aa6334183d /kernel/fork.c
parentcbe9dac379047730e39c7e570eddd27124b0d2dc (diff)
signal: Guarantee that SIGNAL_GROUP_EXIT is set on process exit
Track how many threads have not started exiting and when the last thread starts exiting set SIGNAL_GROUP_EXIT. This guarantees that SIGNAL_GROUP_EXIT will get set when a process exits. In practice this achieves nothing as glibc's implementation of _exit calls sys_group_exit then sys_exit. While glibc's implemenation of pthread_exit calls exit (which cleansup and calls _exit) if it is the last thread and sys_exit if it is the last thread. This means the only way the kernel might observe a process that does not set call exit_group is if the language runtime does not use glibc. With more cleanups I hope to move the decrement of quick_threads earlier. Link: https://lkml.kernel.org/r/87bkukd4tc.fsf_-_@email.froward.int.ebiederm.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 9d44f2d46c69..67813b25a567 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1692,6 +1692,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
return -ENOMEM;
sig->nr_threads = 1;
+ sig->quick_threads = 1;
atomic_set(&sig->live, 1);
refcount_set(&sig->sigcnt, 1);
@@ -2444,6 +2445,7 @@ static __latent_entropy struct task_struct *copy_process(
__this_cpu_inc(process_counts);
} else {
current->signal->nr_threads++;
+ current->signal->quick_threads++;
atomic_inc(&current->signal->live);
refcount_inc(&current->signal->sigcnt);
task_join_group_stop(p);