Add `--enable-asan` and `--enable-ubsan` switches

`configure` now accepts `--enable-asan` and `--enable-ubsan` switches
which results in passing `-fsanitize=address`
and `-fsanitize=undefined`, respectively, to the compiler. Those
flags are enabled in GitHub workflows for ZTS and zloop. Errors
reported by both instrumentations are corrected, except for:

- Memory leak reporting is (temporarily) suppressed. The cost of
  fixing them is relatively high compared to the gains.

- Checksum computing functions in `module/zcommon/zfs_fletcher*`
  have UBSan errors suppressed. It is completely impractical
  to enforce 64-byte payload alignment there due to performance
  impact.

- There's no ASan heap poisoning in `module/zstd/lib/zstd.c`. A custom
  memory allocator is used there rendering that measure
  unfeasible.

- Memory leaks detection has to be suppressed for `cmd/zvol_id`.
  `zvol_id` is run by udev with the help of `ptrace(2)`. Tracing is
  incompatible with memory leaks detection.

Reviewed-by: Ahelenia Ziemiańska <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: szubersk <[email protected]>
Closes #12928 

2 files changed, 3 insertions, 10 deletions

diff --git a/module/zstd/lib/zstd.c b/module/zstd/lib/zstd.c
index 2766e5b74..b57a9ef40 100644
--- a/module/zstd/lib/zstd.c
+++ b/module/zstd/lib/zstd.c
@@ -279,12 +279,9 @@ intptr_t __msan_test_shadow(const volatile void *x, size_t size);
 #endif
 
 /* detects whether we are being compiled under asan */
-#if defined (__has_feature)
-#  if __has_feature(address_sanitizer)
-#    define ADDRESS_SANITIZER 1
-#  endif
-#elif defined(__SANITIZE_ADDRESS__)
+#if defined (ZFS_ASAN_ENABLED)
 #  define ADDRESS_SANITIZER 1
+#  define ZSTD_ASAN_DONT_POISON_WORKSPACE
 #endif
 
 #if defined (ADDRESS_SANITIZER)
diff --git a/module/zstd/zfs_zstd.c b/module/zstd/zfs_zstd.c
index 2c698716c..9ff9ec3ec 100644
--- a/module/zstd/zfs_zstd.c
+++ b/module/zstd/zfs_zstd.c
@@ -207,11 +207,7 @@ static struct zstd_pool *zstd_mempool_dctx;
  * and while ASAN does this, KASAN defines that and does not. So to avoid
  * changing the external code, we do this.
  */
-#if defined(__has_feature)
-#if __has_feature(address_sanitizer)
-#define	ADDRESS_SANITIZER 1
-#endif
-#elif defined(__SANITIZE_ADDRESS__)
+#if defined(ZFS_ASAN_ENABLED)
 #define	ADDRESS_SANITIZER 1
 #endif
 #if defined(_KERNEL) && defined(ADDRESS_SANITIZER)