diff --git a/include/os/linux/spl/sys/kmem.h b/include/os/linux/spl/sys/kmem.h
index 111924303..594425f7b 100644
--- a/include/os/linux/spl/sys/kmem.h
+++ b/include/os/linux/spl/sys/kmem.h
@@ -40,6 +40,9 @@ extern void kmem_strfree(char *str);
 
 #define	kmem_scnprintf	scnprintf
 
+#define	POINTER_IS_VALID(p)	(!((uintptr_t)(p) & 0x3))
+#define	POINTER_INVALIDATE(pp)	(*(pp) = (void *)((uintptr_t)(*(pp)) | 0x1))
+
 /*
  * Memory allocation interfaces
  */
diff --git a/include/os/linux/spl/sys/kmem_cache.h b/include/os/linux/spl/sys/kmem_cache.h
index bd0ad5052..cc9cafa84 100644
--- a/include/os/linux/spl/sys/kmem_cache.h
+++ b/include/os/linux/spl/sys/kmem_cache.h
@@ -98,9 +98,6 @@ extern struct rw_semaphore spl_kmem_cache_sem;
 #define	SPL_MAX_KMEM_ORDER_NR_PAGES	(KMALLOC_MAX_SIZE >> PAGE_SHIFT)
 #endif
 
-#define	POINTER_IS_VALID(p)		0	/* Unimplemented */
-#define	POINTER_INVALIDATE(pp)			/* Unimplemented */
-
 typedef int (*spl_kmem_ctor_t)(void *, void *, int);
 typedef void (*spl_kmem_dtor_t)(void *, void *);
 
diff --git a/module/os/freebsd/zfs/zfs_acl.c b/module/os/freebsd/zfs/zfs_acl.c
index a9318f7a0..9f735dbb5 100644
--- a/module/os/freebsd/zfs/zfs_acl.c
+++ b/module/os/freebsd/zfs/zfs_acl.c
@@ -2414,7 +2414,6 @@ zfs_zaccess(znode_t *zp, int mode, int flags, boolean_t skipaclchk, cred_t *cr,
 		 * read_acl/read_attributes
 		 */
 
-		error = 0;
 		ASSERT3U(working_mode, !=, 0);
 
 		if ((working_mode & (ACE_READ_ACL|ACE_READ_ATTRIBUTES) &&
diff --git a/module/os/freebsd/zfs/zfs_znode.c b/module/os/freebsd/zfs/zfs_znode.c
index 957530243..e691e60a8 100644
--- a/module/os/freebsd/zfs/zfs_znode.c
+++ b/module/os/freebsd/zfs/zfs_znode.c
@@ -1708,6 +1708,7 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 	}
 	ASSERT3U(version, !=, 0);
 	error = zap_update(os, moid, ZPL_VERSION_STR, 8, 1, &version, tx);
+	ASSERT0(error);
 
 	/*
 	 * Create zap object used for SA attribute registration
diff --git a/module/os/linux/spl/spl-kmem-cache.c b/module/os/linux/spl/spl-kmem-cache.c
index 4cceeb8bd..963e7a1ec 100644
--- a/module/os/linux/spl/spl-kmem-cache.c
+++ b/module/os/linux/spl/spl-kmem-cache.c
@@ -791,10 +791,8 @@ spl_kmem_cache_create(const char *name, size_t size, size_t align,
 	} else {
 		unsigned long slabflags = 0;
 
-		if (size > (SPL_MAX_KMEM_ORDER_NR_PAGES * PAGE_SIZE)) {
-			rc = EINVAL;
+		if (size > (SPL_MAX_KMEM_ORDER_NR_PAGES * PAGE_SIZE))
 			goto out;
-		}
 
 #if defined(SLAB_USERCOPY)
 		/*
@@ -815,10 +813,8 @@ spl_kmem_cache_create(const char *name, size_t size, size_t align,
 		skc->skc_linux_cache = kmem_cache_create(
 		    skc->skc_name, size, align, slabflags, NULL);
 #endif
-		if (skc->skc_linux_cache == NULL) {
-			rc = ENOMEM;
+		if (skc->skc_linux_cache == NULL)
 			goto out;
-		}
 	}
 
 	down_write(&spl_kmem_cache_sem);
diff --git a/module/os/linux/spl/spl-thread.c b/module/os/linux/spl/spl-thread.c
index b863945a1..b4ef86a5e 100644
--- a/module/os/linux/spl/spl-thread.c
+++ b/module/os/linux/spl/spl-thread.c
@@ -178,12 +178,11 @@ issig(int why)
 	sigorsets(&set, &task->blocked, &set);
 
 	spin_lock_irq(&task->sighand->siglock);
-	int ret;
 #ifdef HAVE_DEQUEUE_SIGNAL_4ARG
 	enum pid_type __type;
-	if ((ret = dequeue_signal(task, &set, &__info, &__type)) != 0) {
+	if (dequeue_signal(task, &set, &__info, &__type) != 0) {
 #else
-	if ((ret = dequeue_signal(task, &set, &__info)) != 0) {
+	if (dequeue_signal(task, &set, &__info) != 0) {
 #endif
 #ifdef HAVE_SIGNAL_STOP
 		spin_unlock_irq(&task->sighand->siglock);
diff --git a/module/os/linux/zfs/vdev_disk.c b/module/os/linux/zfs/vdev_disk.c
index 2b5c4956d..925ee9d9f 100644
--- a/module/os/linux/zfs/vdev_disk.c
+++ b/module/os/linux/zfs/vdev_disk.c
@@ -425,7 +425,7 @@ vdev_disk_dio_get(dio_request_t *dr)
 	atomic_inc(&dr->dr_ref);
 }
 
-static int
+static void
 vdev_disk_dio_put(dio_request_t *dr)
 {
 	int rc = atomic_dec_return(&dr->dr_ref);
@@ -449,14 +449,11 @@ vdev_disk_dio_put(dio_request_t *dr)
 			zio_delay_interrupt(zio);
 		}
 	}
-
-	return (rc);
 }
 
 BIO_END_IO_PROTO(vdev_disk_physio_completion, bio, error)
 {
 	dio_request_t *dr = bio->bi_private;
-	int rc;
 
 	if (dr->dr_error == 0) {
 #ifdef HAVE_1ARG_BIO_END_IO_T
@@ -470,7 +467,7 @@ BIO_END_IO_PROTO(vdev_disk_physio_completion, bio, error)
 	}
 
 	/* Drop reference acquired by __vdev_disk_physio */
-	rc = vdev_disk_dio_put(dr);
+	vdev_disk_dio_put(dr);
 }
 
 static inline void
@@ -742,7 +739,7 @@ retry:
 	if (dr->dr_bio_count > 1)
 		blk_finish_plug(&plug);
 
-	(void) vdev_disk_dio_put(dr);
+	vdev_disk_dio_put(dr);
 
 	return (error);
 }
diff --git a/module/os/linux/zfs/zfs_acl.c b/module/os/linux/zfs/zfs_acl.c
index 75638399e..db1bb9577 100644
--- a/module/os/linux/zfs/zfs_acl.c
+++ b/module/os/linux/zfs/zfs_acl.c
@@ -2581,7 +2581,6 @@ zfs_fastaccesschk_execute(znode_t *zdp, cred_t *cr)
 	}
 
 	if (uid == KUID_TO_SUID(ZTOI(zdp)->i_uid)) {
-		owner = B_TRUE;
 		if (zdp->z_mode & S_IXUSR) {
 			mutex_exit(&zdp->z_acl_lock);
 			return (0);
@@ -2591,7 +2590,6 @@ zfs_fastaccesschk_execute(znode_t *zdp, cred_t *cr)
 		}
 	}
 	if (groupmember(KGID_TO_SGID(ZTOI(zdp)->i_gid), cr)) {
-		groupmbr = B_TRUE;
 		if (zdp->z_mode & S_IXGRP) {
 			mutex_exit(&zdp->z_acl_lock);
 			return (0);
@@ -2720,7 +2718,6 @@ zfs_zaccess(znode_t *zp, int mode, int flags, boolean_t skipaclchk, cred_t *cr,
 		 * read_acl/read_attributes
 		 */
 
-		error = 0;
 		ASSERT(working_mode != 0);
 
 		if ((working_mode & (ACE_READ_ACL|ACE_READ_ATTRIBUTES) &&
diff --git a/module/os/linux/zfs/zfs_vnops_os.c b/module/os/linux/zfs/zfs_vnops_os.c
index a94af0ea3..47f132a38 100644
--- a/module/os/linux/zfs/zfs_vnops_os.c
+++ b/module/os/linux/zfs/zfs_vnops_os.c
@@ -721,7 +721,6 @@ top:
 
 		if (have_acl)
 			zfs_acl_ids_free(&acl_ids);
-		have_acl = B_FALSE;
 
 		/*
 		 * A directory entry already exists for this name.
@@ -2532,7 +2531,7 @@ out:
 		dmu_tx_commit(tx);
 		if (attrzp) {
 			if (err2 == 0 && handle_eadir)
-				err2 = zfs_setattr_dir(attrzp);
+				err = zfs_setattr_dir(attrzp);
 			zrele(attrzp);
 		}
 		zfs_znode_update_vfs(zp);
diff --git a/module/os/linux/zfs/zfs_znode.c b/module/os/linux/zfs/zfs_znode.c
index d673da384..395e2cf57 100644
--- a/module/os/linux/zfs/zfs_znode.c
+++ b/module/os/linux/zfs/zfs_znode.c
@@ -495,13 +495,11 @@ zfs_set_inode_flags(znode_t *zp, struct inode *ip)
 void
 zfs_znode_update_vfs(znode_t *zp)
 {
-	zfsvfs_t	*zfsvfs;
 	struct inode	*ip;
 	uint32_t	blksize;
 	u_longlong_t	i_blocks;
 
 	ASSERT(zp != NULL);
-	zfsvfs = ZTOZSB(zp);
 	ip = ZTOI(zp);
 
 	/* Skip .zfs control nodes which do not exist on disk. */
@@ -1885,6 +1883,7 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 	}
 	ASSERT(version != 0);
 	error = zap_update(os, moid, ZPL_VERSION_STR, 8, 1, &version, tx);
+	ASSERT(error == 0);
 
 	/*
 	 * Create zap object used for SA attribute registration
diff --git a/module/zcommon/zfs_fletcher.c b/module/zcommon/zfs_fletcher.c
index 44c8f486f..fa9b8447e 100644
--- a/module/zcommon/zfs_fletcher.c
+++ b/module/zcommon/zfs_fletcher.c
@@ -628,7 +628,7 @@ fletcher_4_kstat_data(char *buf, size_t size, void *data)
 		off += snprintf(buf + off, size - off, "%-17s", "fastest");
 		off += snprintf(buf + off, size - off, "%-15s",
 		    fletcher_4_supp_impls[fastest_stat->native]->name);
-		off += snprintf(buf + off, size - off, "%-15s\n",
+		(void) snprintf(buf + off, size - off, "%-15s\n",
 		    fletcher_4_supp_impls[fastest_stat->byteswap]->name);
 	} else {
 		ptrdiff_t id = curr_stat - fletcher_4_stat_data;
@@ -637,7 +637,7 @@ fletcher_4_kstat_data(char *buf, size_t size, void *data)
 		    fletcher_4_supp_impls[id]->name);
 		off += snprintf(buf + off, size - off, "%-15llu",
 		    (u_longlong_t)curr_stat->native);
-		off += snprintf(buf + off, size - off, "%-15llu\n",
+		(void) snprintf(buf + off, size - off, "%-15llu\n",
 		    (u_longlong_t)curr_stat->byteswap);
 	}
 
diff --git a/module/zfs/fm.c b/module/zfs/fm.c
index 3f05d7597..52ea6262a 100644
--- a/module/zfs/fm.c
+++ b/module/zfs/fm.c
@@ -380,8 +380,7 @@ zfs_zevent_wait(zfs_zevent_t *ze)
 			break;
 		}
 
-		error = cv_wait_sig(&zevent_cv, &zevent_lock);
-		if (signal_pending(current)) {
+		if (cv_wait_sig(&zevent_cv, &zevent_lock) == 0) {
 			error = SET_ERROR(EINTR);
 			break;
 		} else if (!list_is_empty(&zevent_list)) {
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index f913c3509..a1717d4d6 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -1081,7 +1081,7 @@ zfs_secpolicy_diff(zfs_cmd_t *zc, nvlist_t *innvl, cred_t *cr)
 	(void) innvl;
 	int error;
 
-	if ((error = secpolicy_sys_config(cr, B_FALSE)) == 0)
+	if (secpolicy_sys_config(cr, B_FALSE) == 0)
 		return (0);
 
 	error = zfs_secpolicy_write_perms(zc->zc_name, ZFS_DELEG_PERM_DIFF, cr);
@@ -1230,8 +1230,8 @@ zfs_secpolicy_tmp_snapshot(zfs_cmd_t *zc, nvlist_t *innvl, cred_t *cr)
 	 */
 	int error;
 
-	if ((error = zfs_secpolicy_write_perms(zc->zc_name,
-	    ZFS_DELEG_PERM_DIFF, cr)) == 0)
+	if (zfs_secpolicy_write_perms(zc->zc_name,
+	    ZFS_DELEG_PERM_DIFF, cr) == 0)
 		return (0);
 
 	error = zfs_secpolicy_snapshot_perms(zc->zc_name, cr);
@@ -1279,8 +1279,7 @@ get_nvlist(uint64_t nvl, uint64_t size, int iflag, nvlist_t **nvp)
 
 	packed = vmem_alloc(size, KM_SLEEP);
 
-	if ((error = ddi_copyin((void *)(uintptr_t)nvl, packed, size,
-	    iflag)) != 0) {
+	if (ddi_copyin((void *)(uintptr_t)nvl, packed, size, iflag) != 0) {
 		vmem_free(packed, size);
 		return (SET_ERROR(EFAULT));
 	}
@@ -2682,7 +2681,6 @@ retry:
 	pair = NULL;
 	while ((pair = nvlist_next_nvpair(genericnvl, pair)) != NULL) {
 		const char *propname = nvpair_name(pair);
-		err = 0;
 
 		propval = pair;
 		if (nvpair_type(pair) == DATA_TYPE_NVLIST) {
@@ -3095,7 +3093,7 @@ zfs_ioc_set_fsacl(zfs_cmd_t *zc)
 	/*
 	 * Verify nvlist is constructed correctly
 	 */
-	if ((error = zfs_deleg_verify_nvlist(fsaclnv)) != 0) {
+	if (zfs_deleg_verify_nvlist(fsaclnv) != 0) {
 		nvlist_free(fsaclnv);
 		return (SET_ERROR(EINVAL));
 	}
diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index 1371e5187..1511f763f 100644
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -1076,7 +1076,7 @@ zvol_create_minors_cb(const char *dsname, void *arg)
 			 * traverse snapshots only, do not traverse children,
 			 * and skip the 'dsname'
 			 */
-			error = dmu_objset_find(dsname,
+			(void) dmu_objset_find(dsname,
 			    zvol_create_snap_minor_cb, (void *)job,
 			    DS_FIND_SNAPSHOTS);
 		}
diff --git a/module/zstd/include/zstd_compat_wrapper.h b/module/zstd/include/zstd_compat_wrapper.h
index 2c4baad27..4e6561f31 100644
--- a/module/zstd/include/zstd_compat_wrapper.h
+++ b/module/zstd/include/zstd_compat_wrapper.h
@@ -73,11 +73,9 @@
 #define	FSE_buildDTable_raw zfs_FSE_buildDTable_raw
 #define	FSE_buildDTable_rle zfs_FSE_buildDTable_rle
 #define	FSE_buildDTable zfs_FSE_buildDTable
-#define	FSE_createDTable zfs_FSE_createDTable
 #define	FSE_decompress_usingDTable zfs_FSE_decompress_usingDTable
 #define	FSE_decompress_wksp zfs_FSE_decompress_wksp
 #define	FSE_decompress zfs_FSE_decompress
-#define	FSE_freeDTable zfs_FSE_freeDTable
 
 /* lib/common/pool.o: */
 #define	POOL_add zfs_POOL_add
diff --git a/module/zstd/lib/common/fse_decompress.c b/module/zstd/lib/common/fse_decompress.c
index bcc2223cc..6b3205c63 100644
--- a/module/zstd/lib/common/fse_decompress.c
+++ b/module/zstd/lib/common/fse_decompress.c
@@ -56,17 +56,6 @@
 
 
 /* Function templates */
-FSE_DTable* FSE_createDTable (unsigned tableLog)
-{
-    if (tableLog > FSE_TABLELOG_ABSOLUTE_MAX) tableLog = FSE_TABLELOG_ABSOLUTE_MAX;
-    return (FSE_DTable*)malloc( FSE_DTABLE_SIZE_U32(tableLog) * sizeof (U32) );
-}
-
-void FSE_freeDTable (FSE_DTable* dt)
-{
-    free(dt);
-}
-
 size_t FSE_buildDTable(FSE_DTable* dt, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog)
 {
     void* const tdPtr = dt+1;   /* because *dt is unsigned, 32-bits aligned on 32-bits */