Ian Neal

Crash consistency issue after acquiring bucket locks

2

## Bug Exposed by crashing after acquiring a lock from `clht_put`. https://github.com/utsaslab/RECIPE/blob/fc508ddfae1ca0d77cf3d3f1b73849e65c223f26/P-CLHT/include/clht_lb_res.h#L306-L312 - Crashing after line 311 here causes the lock to be never released, so the restarted example waits...

Crash consistency bug in clht_gc_free

2

## Bug Exposed by crashing after freeing the hash table in `clht_gc_free`. https://github.com/utsaslab/RECIPE/blob/fc508ddfae1ca0d77cf3d3f1b73849e65c223f26/P-CLHT/src/clht_gc.c#L239-L242 - `pmemobj_free` sets the PMEMoid object to NULL when freeing objects. - With the current design of...

- Make const iterator variables references (fixes `-Werror,-Wrange-loop-construct`) - Add explicit casts from `uint64_t` to `double`

Addresses and closes https://github.com/pmem/redis/issues/219 ; if `pmemobj_open` also fails, `POBJ_ROOT(...)` will cause a segfault, so check for NULL first.

https://github.com/pmem/redis/blob/4e622e75a596813fc1d2a3d1b569427302fad602/src/server.c#L4015-L4019 - If the pool is corrupted or is otherwise unopenable, [pmemobj_open(...)](https://pmem.io/pmdk/manpages/linux/v1.10/libpmemobj/pmemobj_open.3) will return NULL, causing a SEGFAULT during initialization (i.e., at POBJ_ROOT).

https://github.com/e-alizadeh/medium/blob/b84a9d6caf3805a1b67ac41d4fbcca56af17731f/notebooks/intro_to_dtw.ipynb?short_path=9837e37#L151 Should be: ```python dist[i,j] = math.sqrt((x[j]-y[i])**2) ``` Or ```python dist[i,j] = math.abs(x[j]-y[i]) ``` If I'm not mistaken.