History

meiravgri 2e854bccc6 Fix async safety in signal handlers (#12658 ) see discussion from after https://github.com/redis/redis/pull/12453 was merged ---- This PR replaces signals that are not considered async-signal-safe (AS-safe) with safe calls. #### 1. serverLog() and serverLogFromHandler() `serverLog` uses unsafe calls. It was decided that we will avoid `serverLog` calls by the signal handlers when: * The signal is not fatal, such as SIGALRM. In these cases, we prefer using `serverLogFromHandler` which is the safe version of `serverLog`. Note they have different prompts: `serverLog`: `62220:M 26 Oct 2023 14:39:04.526 # <msg>` `serverLogFromHandler`: `62220:signal-handler (1698331136) <msg>` * The code was added recently. Calls to `serverLog` by the signal handler have been there ever since Redis exists and it hasn't caused problems so far. To avoid regression, from now we should use `serverLogFromHandler` #### 2. `snprintf` `fgets` and `strtoul`(base = 16) --------> `_safe_snprintf`, `fgets_async_signal_safe`, `string_to_hex` The safe version of `snprintf` was taken from [here](`8cfc4ca5e7/src/mc_util.c (L754)`) #### 3. fopen(), fgets(), fclose() --------> open(), read(), close() #### 4. opendir(), readdir(), closedir() --------> open(), syscall(SYS_getdents64), close() #### 5. Threads_mngr sync mechanisms * waiting for the thread to generate stack trace: semaphore --------> busy-wait * `globals_rw_lock` was removed: as we are not using malloc and the semaphore anymore we don't need to protect `ThreadsManager_cleanups`. #### 6. Stacktraces buffer The initial problem was that we were not able to safely call malloc within the signal handler. To solve that we created a buffer on the stack of `writeStacktraces` and saved it in a global pointer, assuming that under normal circumstances, the function `writeStacktraces` would complete before any thread attempted to write to it. However, if threads lag behind, they might access this global pointer after it no longer belongs to the `writeStacktraces` stack, potentially corrupting memory. To address this, various solutions were discussed [here](https://github.com/redis/redis/pull/12658#discussion_r1390442896) Eventually, we decided to create a pipe at server startup that will remain valid as long as the process is alive. We chose this solution due to its minimal memory usage, and since `write()` and `read()` are atomic operations. It ensures that stack traces from different threads won't mix. The stacktraces collection process is now as follows: * Cleaning the pipe to eliminate writes of late threads from previous runs. * Each thread writes to the pipe its stacktrace * Waiting for all the threads to mark completion or until a timeout (2 sec) is reached * Reading from the pipe to print the stacktraces. #### 7. Changes that were considered and eventually were dropped * replace watchdog timer with a POSIX timer: according to [settimer man](https://linux.die.net/man/2/setitimer) > POSIX.1-2008 marks getitimer() and setitimer() obsolete, recommending the use of the POSIX timers API ([timer_gettime](https://linux.die.net/man/2/timer_gettime)(2), [timer_settime](https://linux.die.net/man/2/timer_settime)(2), etc.) instead. However, although it is supposed to conform to POSIX std, POSIX timers API is not supported on Mac. You can take a look here at the Linux implementation: [here](`c7562ee135`) To avoid messing up the code, and uncertainty regarding compatibility, it was decided to drop it for now. * avoid using sds (uses malloc) in logConfigDebugInfo It was considered to print config info instead of using sds, however apparently, `logConfigDebugInfo` does more than just print the sds, so it was decided this fix is out of this issue scope. #### 8. fix Signal mask check The check `signum & sig_mask` intended to indicate whether the signal is blocked by the thread was incorrect. Actually, the bit position in the signal mask corresponds to the signal number. We fixed this by changing the condition to: `sig_mask & (1L << (sig_num - 1))` #### 9. Unrelated changes both `fork.tcl `and `util.tcl` implemented a function called `count_log_message` expecting different parameters. This caused confusion when trying to run daily tests with additional test parameters to run a specific test. The `count_log_message` in `fork.tcl` was removed and the calls were replaced with calls to `count_log_message` located in `util.tcl` --------- Co-authored-by: Ozan Tezcan <ozantezcan@gmail.com> Co-authored-by: Oran Agra <oran@redislabs.com>		2023-11-23 13:22:20 +02:00
..
assets	fix `GEORADIUS[BYMEMBER]` `STORE` & `STOREDIST` args spec (#12151 )	2023-05-09 14:24:37 +03:00
cluster	Fix timing issue in CLUSTER SLAVE / REPLICAS consistent test (#12774 )	2023-11-19 11:09:33 +02:00
helpers	When redis-cli received ASK, it didn't handle it (#8930 )	2021-08-02 14:59:08 +03:00
integration	Fix async safety in signal handlers (#12658 )	2023-11-23 13:22:20 +02:00
modules	Before evicted and before expired server events are not executed inside an execution unit. (#12733 )	2023-11-08 09:28:22 +02:00
sentinel	Fix flaky SENTINEL RESET test (#12437 )	2023-08-10 08:58:52 +03:00
support	Replace cluster metadata with slot specific dictionaries (#11695 )	2023-10-14 23:58:26 -07:00
tmp	minor fixes to the new test suite, html doc updated	2010-05-14 18:48:33 +02:00
unit	Fix async safety in signal handlers (#12658 )	2023-11-23 13:22:20 +02:00
README.md	Make assert_refcount skip the OBJECT REFCOUNT check with needs:debug tag (#11487 )	2022-11-22 16:38:27 +02:00
instances.tcl	Add reply_schema to command json files (internal for now) (#10273 )	2023-03-11 10:14:16 +02:00
test_helper.tcl	Dump server logs when corrupt fuzzer reports crash (#12612 )	2023-09-27 09:08:18 +03:00

README.md

Redis Test Suite

The normal execution mode of the test suite involves starting and manipulating local redis-server instances, inspecting process state, log files, etc.

The test suite also supports execution against an external server, which is enabled using the --host and --port parameters. When executing against an external server, tests tagged external:skip are skipped.

There are additional runtime options that can further adjust the test suite to match different external server configurations:

Option	Impact
`--singledb`	Only use database 0, don't assume others are supported.
`--ignore-encoding`	Skip all checks for specific encoding.
`--ignore-digest`	Skip key value digest validations.
`--cluster-mode`	Run in strict Redis Cluster compatibility mode.
`--large-memory`	Enables tests that consume more than 100mb

Tags

Tags are applied to tests to classify them according to the subsystem they test, but also to indicate compatibility with different run modes and required capabilities.

Tags can be applied in different context levels:

start_server context
tags context that bundles several tests together
A single test context.

The following compatibility and capability tags are currently used:

Tag	Indicates
`external:skip`	Not compatible with external servers.
`cluster:skip`	Not compatible with `--cluster-mode`.
`large-memory`	Test that requires more than 100mb
`tls:skip`	Not compatible with `--tls`.
`needs:repl`	Uses replication and needs to be able to `SYNC` from server.
`needs:debug`	Uses the `DEBUG` command or other debugging focused commands (like `OBJECT REFCOUNT`).
`needs:pfdebug`	Uses the `PFDEBUG` command.
`needs:config-maxmemory`	Uses `CONFIG SET` to manipulate memory limit, eviction policies, etc.
`needs:config-resetstat`	Uses `CONFIG RESETSTAT` to reset statistics.
`needs:reset`	Uses `RESET` to reset client connections.
`needs:save`	Uses `SAVE` or `BGSAVE` to create an RDB file.

When using an external server (--host and --port), filtering using the external:skip tags is done automatically.

When using --cluster-mode, filtering using the cluster:skip tag is done automatically.

When not using --large-memory, filtering using the largemem:skip tag is done automatically.

In addition, it is possible to specify additional configuration. For example, to run tests on a server that does not permit SYNC use:

./runtest --host <host> --port <port> --tags -needs:repl