coredump: elf_core_dump: skip kernel threads
linux_binfmt->core_dump() runs before the process does exit_aio(), this
means that we can hit the kernel thread which shares the same ->mm.
Afaics, nothing really bad can happen, but perhaps it makes sense to fix
this minor bug.
It is sad we have to iterate over all threads in system and use
GFP_ATOMIC. Hopefully we can kill theses ugly do_each_thread()s, but this
needs some nontrivial changes in mm_struct and do_coredump.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 639d2d8..bad7d87 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1520,6 +1520,9 @@
rcu_read_lock();
do_each_thread(g, p)
if (p->mm == dump_task->mm) {
+ if (p->flags & PF_KTHREAD)
+ continue;
+
t = kzalloc(offsetof(struct elf_thread_core_info,
notes[info->thread_notes]),
GFP_ATOMIC);
@@ -1724,6 +1727,9 @@
rcu_read_lock();
do_each_thread(g, p)
if (current->mm == p->mm && current != p) {
+ if (p->flags & PF_KTHREAD)
+ continue;
+
ets = kzalloc(sizeof(*ets), GFP_ATOMIC);
if (!ets) {
rcu_read_unlock();
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index d051a32..71bcc4b 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1626,6 +1626,9 @@
rcu_read_lock();
do_each_thread(g,p)
if (current->mm == p->mm && current != p) {
+ if (p->flags & PF_KTHREAD)
+ continue;
+
tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
if (!tmp) {
rcu_read_unlock();