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Commit 24d5288f authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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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: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 15b9f360

fs/binfmt_elf.c

+6 −0
Original line number Diff line number Diff line
@@ -1520,6 +1520,9 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, 
	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 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, 
		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();

fs/binfmt_elf_fdpic.c

+3 −0
Original line number Diff line number Diff line
@@ -1626,6 +1626,9 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs, 
		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();