Commit f6979ade authored Jun 05, 2015 by Bart Van Assche Committed by James Bottomley Aug 12, 2015

libfc: Fix fc_exch_recv_req() error path



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]
 kthread+0x10a/0x120
 ret_from_fork+0x42/0x70

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

parent 660d0831

drivers/scsi/libfc/fc_exch.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -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);
		}

		spin_lock_bh(&ep->ex_lock);
		@@ -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);

		fc_exch_release(ep);
		return;
		@@ -1695,7 +1694,8 @@ static void fc_exch_abts_resp(struct fc_exch ep, struct fc_frame fp)
		fc_exch_hold(ep);
		if (!rc)
		fc_exch_delete(ep);
		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);
		fc_exch_release(ep);