LU-14733 o2iblnd: Move racy NULL assignment
From: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
kiblnd_fmr_pool_unmap() can race map and subsequent processing
because of this flaw in unmap:
if (frd) {
frd->frd_valid = false;
spin_lock(&fps->fps_lock);
list_add_tail(&frd->frd_list, &fpo->fast_reg.fpo_pool_list);
spin_unlock(&fps->fps_lock);
fmr->fmr_frd = NULL;
}
The fmr can be pulled off the list in kiblnd_fmr_pool_unmap() on
another CPU an fmr_frd could be in a state of flux and
potentially be seen incorrectly later on as the kib_tx is processed.
Fix my moving the fmr_frd assignment to before the fmr is added to the
list.
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Change-Id: Ibddf132a363ecfe9db3cc06287cec873c021d2fb
---
lnet/klnds/o2iblnd/o2iblnd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lnet/klnds/o2iblnd/o2iblnd.c b/lnet/klnds/o2iblnd/o2iblnd.c
index b28c5b2..f3028b4 100644
--- a/lnet/klnds/o2iblnd/o2iblnd.c
+++ b/lnet/klnds/o2iblnd/o2iblnd.c
@@ -1751,10 +1751,10 @@ kiblnd_fmr_pool_unmap(struct kib_fmr *fmr, int status)
if (frd) {
frd->frd_valid = false;
+ fmr->fmr_frd = NULL;
spin_lock(&fps->fps_lock);
list_add_tail(&frd->frd_list, &fpo->fast_reg.fpo_pool_list);
spin_unlock(&fps->fps_lock);
- fmr->fmr_frd = NULL;
}
}
fmr->fmr_pool = NULL;