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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/litmus-tests/rcu/RCU+sync+free.litmus | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/litmus-tests/rcu/RCU+sync+free.litmus')
-rw-r--r-- | Documentation/litmus-tests/rcu/RCU+sync+free.litmus | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/litmus-tests/rcu/RCU+sync+free.litmus b/Documentation/litmus-tests/rcu/RCU+sync+free.litmus new file mode 100644 index 000000000..4ee67e12f --- /dev/null +++ b/Documentation/litmus-tests/rcu/RCU+sync+free.litmus @@ -0,0 +1,42 @@ +C RCU+sync+free + +(* + * Result: Never + * + * This litmus test demonstrates that an RCU reader can never see a write that + * follows a grace period, if it did not see writes that precede that grace + * period. + * + * This is a typical pattern of RCU usage, where the write before the grace + * period assigns a pointer, and the writes following the grace period destroy + * the object that the pointer used to point to. + * + * This is one implication of the RCU grace-period guarantee, which says (among + * other things) that an RCU read-side critical section cannot span a grace period. + *) + +{ +int x = 1; +int *y = &x; +int z = 1; +} + +P0(int *x, int *z, int **y) +{ + int *r0; + int r1; + + rcu_read_lock(); + r0 = rcu_dereference(*y); + r1 = READ_ONCE(*r0); + rcu_read_unlock(); +} + +P1(int *x, int *z, int **y) +{ + rcu_assign_pointer(*y, z); + synchronize_rcu(); + WRITE_ONCE(*x, 0); +} + +exists (0:r0=x /\ 0:r1=0) |