[PATCH 3.16.y-ckt 105/130] libfc: Fix fc_exch_recv_req() error path

From: Luis Henriques
Date: Fri Sep 04 2015 - 09:20:58 EST

3.16.7-ckt17 -stable review patch. If anyone has any objections, please let me know.


From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>

commit f6979adeaab578f8ca14fdd32b06ddee0d9d3314 upstream.

Due to patch "libfc: Do not invoke the response handler after
fc_exch_done()" (commit ID 7030fd62) the lport_recv() call
in fc_exch_recv_req() is passed a dangling pointer. Avoid this
by moving the fc_frame_free() call from fc_invoke_resp() to its
callers. This patch fixes the following crash:

general protection fault: 0000 [#3] PREEMPT SMP
RIP: fc_lport_recv_req+0x72/0x280 [libfc]
Call Trace:
fc_exch_recv+0x642/0xde0 [libfc]
fcoe_percpu_receive_thread+0x46a/0x5ed [fcoe]

Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Signed-off-by: Vasu Dev <vasu.dev@xxxxxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/scsi/libfc/fc_exch.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 1b3a09473452..30f9ef0c0d4f 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -733,8 +733,6 @@ static bool fc_invoke_resp(struct fc_exch *ep, struct fc_seq *sp,
if (resp) {
resp(sp, fp, arg);
res = true;
- } else if (!IS_ERR(fp)) {
- fc_frame_free(fp);

@@ -1596,7 +1594,8 @@ static void fc_exch_recv_seq_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
* If new exch resp handler is valid then call that
* first.
- fc_invoke_resp(ep, sp, fp);
+ if (!fc_invoke_resp(ep, sp, fp))
+ fc_frame_free(fp);

@@ -1695,7 +1694,8 @@ static void fc_exch_abts_resp(struct fc_exch *ep, struct fc_frame *fp)
if (!rc)
- fc_invoke_resp(ep, sp, fp);
+ if (!fc_invoke_resp(ep, sp, fp))
+ fc_frame_free(fp);
if (has_rec)
fc_exch_timer_set(ep, ep->r_a_tov);
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