coredump: construct the list of coredumping threads at startup time
binfmt->core_dump() has to iterate over the all threads in system in order
to find the coredumping threads and construct the list using the
GFP_ATOMIC allocations.
With this patch each thread allocates the list node on exit_mm()'s stack and
adds itself to the list.
This allows us to do further changes:
- simplify ->core_dump()
- change exit_mm() to clear ->mm first, then wait for ->core_done.
this makes the coredumping process visible to oom_kill
- kill mm->core_done
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: 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/exec.c b/fs/exec.c
index b8ee842..fe2873b 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1604,6 +1604,8 @@
init_completion(&mm->core_done);
init_completion(&core_state->startup);
+ core_state->dumper.task = tsk;
+ core_state->dumper.next = NULL;
core_waiters = zap_threads(tsk, mm, core_state, exit_code);
up_write(&mm->mmap_sem);