no deadlock
initial: a = 1, b = 1, c = 1
| thread 1 | thread 2 |
|---|---|
| P(a) | P(c) |
| P(b) | P(b) |
| V(b) | V(b) |
| P(c) | V(c) |
| V(c) | —- |
| V(a) | —- |
thread 2 doesn’t manipulate mutex a and initial a is 1, so P(a), V(a) don’t affect deadlock status.
| thread 1 | thread 2 |
|---|---|
| P(b) | P(c) |
| V(b) | P(b) |
| P(c) | V(b) |
| V(c) | V(c) |
+
|
|
+ +----------+
V(c)| | |
| | |
+ | |
| | |
| | |
+ +----------+ | |
V(b)| | | | |
| | | | |
+ | | | |
| | | | |
| | | | |
+ +----------+ | |
P(b)| | |
| | |
+ | |
| | |
| | |
+ +----------+
P(c)|
|
+
|
|
+----+----+----+----+----+----+----+----+----+ thread 1
P(b) V(b) P(c) V(c)