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authorEddy Wu <itseddy0402@gmail.com>2020-11-07 09:47:22 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-11-08 22:18:39 +0300
commitb4e00444cab4c3f3fec876dc0cccc8cbb0d1a948 (patch)
tree72e12c5023507b955eed888011eca19f579a38ed /kernel/fork.c
parent9dbc1c03eeb534b82647cccb059aca0685d449a7 (diff)
downloadlinux-b4e00444cab4c3f3fec876dc0cccc8cbb0d1a948.tar.xz
fork: fix copy_process(CLONE_PARENT) race with the exiting ->real_parent
current->group_leader->exit_signal may change during copy_process() if current->real_parent exits. Move the assignment inside tasklist_lock to avoid the race. Signed-off-by: Eddy Wu <eddy_wu@trendmicro.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 32083db7a2a2..6d266388d380 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2167,14 +2167,9 @@ static __latent_entropy struct task_struct *copy_process(
/* ok, now we should be set up.. */
p->pid = pid_nr(pid);
if (clone_flags & CLONE_THREAD) {
- p->exit_signal = -1;
p->group_leader = current->group_leader;
p->tgid = current->tgid;
} else {
- if (clone_flags & CLONE_PARENT)
- p->exit_signal = current->group_leader->exit_signal;
- else
- p->exit_signal = args->exit_signal;
p->group_leader = p;
p->tgid = p->pid;
}
@@ -2218,9 +2213,14 @@ static __latent_entropy struct task_struct *copy_process(
if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
p->real_parent = current->real_parent;
p->parent_exec_id = current->parent_exec_id;
+ if (clone_flags & CLONE_THREAD)
+ p->exit_signal = -1;
+ else
+ p->exit_signal = current->group_leader->exit_signal;
} else {
p->real_parent = current;
p->parent_exec_id = current->self_exec_id;
+ p->exit_signal = args->exit_signal;
}
klp_copy_process(p);