# HG changeset patch

# User Daiki Ueno <dueno@redhat.com>

# Date 1521731296 -3600

#      Thu Mar 22 16:08:16 2018 +0100

# Node ID 6ae3ab8a1e7b4161f3f8eee90db7a745acced408

# Parent  dedf5290c679153e5b3555ba9c711fe62323c156

Bug 1447628, devslot: avoid deadlock when re-inserting a token, r=rrelyea

diff --git a/lib/dev/devslot.c b/lib/dev/devslot.c

--- a/lib/dev/devslot.c

+++ b/lib/dev/devslot.c

@@ -96,10 +96,16 @@ nssSlot_ResetDelay(

 }

 static PRBool

-within_token_delay_period(const NSSSlot *slot)

+token_status_checked(const NSSSlot *slot)

 {

     PRIntervalTime time;

     int lastPingState = slot->lastTokenPingState;

+    /* When called from the same thread, that means

+     * nssSlot_IsTokenPresent() is called recursively through

+     * nssSlot_Refresh(). Return immediately in that case. */

+    if (slot->isPresentThread == PR_GetCurrentThread()) {

+        return PR_TRUE;

+    }

     /* Set the delay time for checking the token presence */

     if (s_token_delay_time == 0) {

         s_token_delay_time = PR_SecondsToInterval(NSSSLOT_TOKEN_DELAY_TIME);

@@ -130,7 +136,7 @@ nssSlot_IsTokenPresent(

     /* avoid repeated calls to check token status within set interval */

     PZ_Lock(slot->isPresentLock);

-    if (within_token_delay_period(slot)) {

+    if (token_status_checked(slot)) {

         CK_FLAGS ckFlags = slot->ckFlags;

         PZ_Unlock(slot->isPresentLock);

         return ((ckFlags & CKF_TOKEN_PRESENT) != 0);

@@ -146,12 +152,12 @@ nssSlot_IsTokenPresent(

     /* set up condition so only one thread is active in this part of the code at a time */

     PZ_Lock(slot->isPresentLock);

-    while (slot->inIsPresent) {

+    while (slot->isPresentThread) {

         PR_WaitCondVar(slot->isPresentCondition, 0);

     }

     /* if we were one of multiple threads here, the first thread will have

      * given us the answer, no need to make more queries of the token. */

-    if (within_token_delay_period(slot)) {

+    if (token_status_checked(slot)) {

         CK_FLAGS ckFlags = slot->ckFlags;

         PZ_Unlock(slot->isPresentLock);

         return ((ckFlags & CKF_TOKEN_PRESENT) != 0);

@@ -159,7 +165,7 @@ nssSlot_IsTokenPresent(

     /* this is the winning thread, block all others until we've determined

      * if the token is present and that it needs initialization. */

     slot->lastTokenPingState = nssSlotLastPingState_Update;

-    slot->inIsPresent = PR_TRUE;

+    slot->isPresentThread = PR_GetCurrentThread();

     PZ_Unlock(slot->isPresentLock);

@@ -257,7 +263,7 @@ done:

         slot->lastTokenPingTime = PR_IntervalNow();

         slot->lastTokenPingState = nssSlotLastPingState_Valid;

     }

-    slot->inIsPresent = PR_FALSE;

+    slot->isPresentThread = NULL;

     PR_NotifyAllCondVar(slot->isPresentCondition);

     PZ_Unlock(slot->isPresentLock);

     return isPresent;

diff --git a/lib/dev/devt.h b/lib/dev/devt.h

--- a/lib/dev/devt.h

+++ b/lib/dev/devt.h

@@ -92,7 +92,7 @@ struct NSSSlotStr {

     PK11SlotInfo *pk11slot;

     PZLock *isPresentLock;

     PRCondVar *isPresentCondition;

-    PRBool inIsPresent;

+    PRThread *isPresentThread;

 };

 struct nssSessionStr {

diff --git a/lib/pk11wrap/dev3hack.c b/lib/pk11wrap/dev3hack.c

--- a/lib/pk11wrap/dev3hack.c

+++ b/lib/pk11wrap/dev3hack.c

@@ -122,7 +122,7 @@ nssSlot_CreateFromPK11SlotInfo(NSSTrustD

     rvSlot->lock = (nss3slot->isThreadSafe) ? NULL : nss3slot->sessionLock;

     rvSlot->isPresentLock = PZ_NewLock(nssiLockOther);

     rvSlot->isPresentCondition = PR_NewCondVar(rvSlot->isPresentLock);

-    rvSlot->inIsPresent = PR_FALSE;

+    rvSlot->isPresentThread = NULL;

     rvSlot->lastTokenPingState = nssSlotLastPingState_Reset;

     return rvSlot;

 }