git: 1616f7d4b57b - stable/14 - bhyve: avoid a potential deadlock

From: Corvin Köhne <corvink_at_FreeBSD.org>
Date: Tue, 12 Nov 2024 07:55:40 UTC
The branch stable/14 has been updated by corvink:

URL: https://cgit.FreeBSD.org/src/commit/?id=1616f7d4b57bd463431ee2af7710b4f9d96db6ea

commit 1616f7d4b57bd463431ee2af7710b4f9d96db6ea
Author:     Pierre Pronchery <khorben@defora.org>
AuthorDate: 2024-08-05 07:46:01 +0000
Commit:     Corvin Köhne <corvink@FreeBSD.org>
CommitDate: 2024-11-12 07:54:21 +0000

    bhyve: avoid a potential deadlock
    
    This unlocks a mutex in an error path, that would otherwise remain locked and
    potentially cause a deadlock later on.
    
    Reported by:            Coverity Scan
    CID:                    1521334
    Reviewed by:            corvink, markj
    MFC after:              1 week
    Sponsored by:           The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D45401
    
    (cherry picked from commit 1f3bfc60550cdd019f00bf6d274db762fda4ed2c)
---
 usr.sbin/bhyve/tpm_intf_crb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/usr.sbin/bhyve/tpm_intf_crb.c b/usr.sbin/bhyve/tpm_intf_crb.c
index 6aeafe7f0ec1..95cd8b1aae31 100644
--- a/usr.sbin/bhyve/tpm_intf_crb.c
+++ b/usr.sbin/bhyve/tpm_intf_crb.c
@@ -349,8 +349,10 @@ tpm_crb_mem_handler(struct vcpu *vcpu __unused, const int dir,
 			pthread_mutex_lock(&crb->mutex);
 			tpm_crb_mmiocpy(&start, val, size);
 
-			if (!start.start || crb->regs.ctrl_start.start)
+			if (!start.start || crb->regs.ctrl_start.start) {
+				pthread_mutex_unlock(&crb->mutex);
 				break;
+			}
 
 			crb->regs.ctrl_start.start = true;