pespin has submitted this change. ( 
https://gerrit.osmocom.org/c/libosmo-abis/+/38969?usp=email )

Change subject: e1_input: Guard against crash by users calling reentrant 
e1inp_sign_link_destroy()
......................................................................

e1_input: Guard against crash by users calling reentrant 
e1inp_sign_link_destroy()

Related: osmo-bsc.git Change-Id Ice71b3143f167482e4a23759012b58e9ee13bfc0
Related: osmo-bts.git Change-Id Ibc06cdc2d2cd2028b7676fa0c3211ae251cca587
Change-Id: Ib761cece68f1d809e27194bc5cc2eb15ad2ae4eb
---
M src/e1_input.c
1 file changed, 11 insertions(+), 1 deletion(-)

Approvals:
  osmith: Looks good to me, but someone else must approve
  Jenkins Builder: Verified
  laforge: Looks good to me, but someone else must approve
  fixeria: Looks good to me, approved




diff --git a/src/e1_input.c b/src/e1_input.c
index 76adbd9..066a572 100644
--- a/src/e1_input.c
+++ b/src/e1_input.c
@@ -810,7 +810,17 @@
 {
        struct msgb *msg;

-       llist_del(&link->list);
+       /* Catch upper layers behaving wrongly, calling 
e1inp_sign_link_destroy()
+        * and then during the driver->close() callback below ending up calling
+        * this function again deeper in the call stack in the same code path. 
*/
+       if (llist_empty(&link->list)) {
+               LOGP(DLINP, LOGL_ERROR, "Fix your application, "
+                    "caught reentrant e1inp_sign_link_destroy(%p)!\n", link);
+               return;
+       }
+       /* Use llist_del_init() to catch double destroy above: */
+       llist_del_init(&link->list);
+
        while (!llist_empty(&link->tx_list)) {
                msg = msgb_dequeue(&link->tx_list);
                msgb_free(msg);

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Gerrit-MessageType: merged
Gerrit-Project: libosmo-abis
Gerrit-Branch: master
Gerrit-Change-Id: Ib761cece68f1d809e27194bc5cc2eb15ad2ae4eb
Gerrit-Change-Number: 38969
Gerrit-PatchSet: 2
Gerrit-Owner: pespin <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: osmith <[email protected]>
Gerrit-Reviewer: pespin <[email protected]>

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