From b73aa56ee91cd88a4977033cfd2a18d6b25dddde Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Thu, 13 Oct 2016 15:10:49 +0200 Subject: [PATCH] scsi: libfc: safeguard against invalid exchange index The cached exchange index might be invalid, in which case we should drop down to allocate a new one. And we should not try to access an invalid exchange when responding to a BA_ABTS. Signed-off-by: Hannes Reinecke Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/scsi/libfc/fc_exch.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c index 99cc5a941997..7b47ab1389ca 100644 --- a/drivers/scsi/libfc/fc_exch.c +++ b/drivers/scsi/libfc/fc_exch.c @@ -827,14 +827,18 @@ static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport, /* peek cache of free slot */ if (pool->left != FC_XID_UNKNOWN) { - index = pool->left; - pool->left = FC_XID_UNKNOWN; - goto hit; + if (!WARN_ON(fc_exch_ptr_get(pool, pool->left))) { + index = pool->left; + pool->left = FC_XID_UNKNOWN; + goto hit; + } } if (pool->right != FC_XID_UNKNOWN) { - index = pool->right; - pool->right = FC_XID_UNKNOWN; - goto hit; + if (!WARN_ON(fc_exch_ptr_get(pool, pool->right))) { + index = pool->right; + pool->right = FC_XID_UNKNOWN; + goto hit; + } } index = pool->next_index; @@ -1782,7 +1786,10 @@ static void fc_exch_recv_bls(struct fc_exch_mgr *mp, struct fc_frame *fp) fc_frame_free(fp); break; case FC_RCTL_BA_ABTS: - fc_exch_recv_abts(ep, fp); + if (ep) + fc_exch_recv_abts(ep, fp); + else + fc_frame_free(fp); break; default: /* ignore junk */ fc_frame_free(fp); -- 2.20.1