+ zram-validate-parameters-in-each-backends-setup_params.patch added to mm-new branch

The patch titled
     Subject: zram: validate parameters in each backend's setup_params
has been added to the -mm mm-new branch.  Its filename is
     zram-validate-parameters-in-each-backends-setup_params.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-validate-parameters-in-each-backends-setup_params.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
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fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Haoqin Huang <[email protected]>
Subject: zram: validate parameters in each backend's setup_params
Date: Tue, 4 Aug 2026 17:38:40 +0800

Dict and level parameters are silently accepted even for backends that do
not support them.  Validate these parameters in each backend's
.setup_params() to reject unsupported combinations and out-of-range levels
with a specific error message.

Link: https://lore.kernel.org/[email protected]
Signed-off-by: Haoqin Huang <[email protected]>
Signed-off-by: Rongwei Wang <[email protected]>
Reviewed-by: Sergey Senozhatsky <[email protected]>
Tested-by: Sergey Senozhatsky <[email protected]>
Cc: David Sterba <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Nick Terrell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 drivers/block/zram/backend_842.c     |    8 ++++++++
 drivers/block/zram/backend_deflate.c |   13 ++++++++++++-
 drivers/block/zram/backend_lz4.c     |    6 +++++-
 drivers/block/zram/backend_lz4hc.c   |   12 +++++++++++-
 drivers/block/zram/backend_lzo.c     |    8 ++++++++
 drivers/block/zram/backend_lzorle.c  |    8 ++++++++
 drivers/block/zram/backend_zstd.c    |    7 ++++++-
 7 files changed, 58 insertions(+), 4 deletions(-)

--- a/drivers/block/zram/backend_842.c~zram-validate-parameters-in-each-backends-setup_params
+++ a/drivers/block/zram/backend_842.c
@@ -15,6 +15,14 @@ static void release_params_842(struct zc
 
 static int setup_params_842(struct zcomp_params *params)
 {
+	if (params->dict_sz) {
+		pr_err("dictionary is not supported\n");
+		return -EOPNOTSUPP;
+	}
+	if (params->level != ZCOMP_PARAM_NOT_SET) {
+		pr_err("compression level is not supported\n");
+		return -EOPNOTSUPP;
+	}
 	return 0;
 }
 
--- a/drivers/block/zram/backend_deflate.c~zram-validate-parameters-in-each-backends-setup_params
+++ a/drivers/block/zram/backend_deflate.c
@@ -24,8 +24,19 @@ static void deflate_release_params(struc
 
 static int deflate_setup_params(struct zcomp_params *params)
 {
-	if (params->level == ZCOMP_PARAM_NOT_SET)
+	if (params->dict_sz) {
+		pr_err("dictionary is not supported\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (params->level == ZCOMP_PARAM_NOT_SET) {
 		params->level = Z_DEFAULT_COMPRESSION;
+	} else if (params->level < Z_DEFAULT_COMPRESSION ||
+		   params->level > Z_BEST_COMPRESSION) {
+		pr_err("invalid compression level %d\n", params->level);
+		return -EINVAL;
+	}
+
 	if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET) {
 		params->deflate.winbits = DEFLATE_DEF_WINBITS;
 	} else {
--- a/drivers/block/zram/backend_lz4.c~zram-validate-parameters-in-each-backends-setup_params
+++ a/drivers/block/zram/backend_lz4.c
@@ -32,8 +32,12 @@ static int lz4_setup_params(struct zcomp
 	LZ4_stream_t *dict_stream;
 	int ret;
 
-	if (params->level == ZCOMP_PARAM_NOT_SET)
+	if (params->level == ZCOMP_PARAM_NOT_SET) {
 		params->level = LZ4_ACCELERATION_DEFAULT;
+	} else if (params->level < LZ4_ACCELERATION_DEFAULT) {
+		pr_err("invalid compression level %d\n", params->level);
+		return -EINVAL;
+	}
 
 	if (!params->dict || !params->dict_sz)
 		return 0;
--- a/drivers/block/zram/backend_lz4hc.c~zram-validate-parameters-in-each-backends-setup_params
+++ a/drivers/block/zram/backend_lz4hc.c
@@ -22,8 +22,18 @@ static void lz4hc_release_params(struct
 
 static int lz4hc_setup_params(struct zcomp_params *params)
 {
-	if (params->level == ZCOMP_PARAM_NOT_SET)
+	if (params->level == ZCOMP_PARAM_NOT_SET) {
 		params->level = LZ4HC_DEFAULT_CLEVEL;
+	} else if (params->level < 1 || params->level > LZ4HC_MAX_CLEVEL) {
+		/*
+		 * Use < 1 rather than < LZ4HC_MIN_CLEVEL here because
+		 * LZ4HC_compress_generic() only clamps levels below 1
+		 * (levels 1 and 2 are valid). LZ4HC_MIN_CLEVEL (3) is
+		 * advisory and not enforced by the library.
+		 */
+		pr_err("invalid compression level %d\n", params->level);
+		return -EINVAL;
+	}
 
 	return 0;
 }
--- a/drivers/block/zram/backend_lzo.c~zram-validate-parameters-in-each-backends-setup_params
+++ a/drivers/block/zram/backend_lzo.c
@@ -14,6 +14,14 @@ static void lzo_release_params(struct zc
 
 static int lzo_setup_params(struct zcomp_params *params)
 {
+	if (params->dict_sz) {
+		pr_err("dictionary is not supported\n");
+		return -EOPNOTSUPP;
+	}
+	if (params->level != ZCOMP_PARAM_NOT_SET) {
+		pr_err("compression level is not supported\n");
+		return -EOPNOTSUPP;
+	}
 	return 0;
 }
 
--- a/drivers/block/zram/backend_lzorle.c~zram-validate-parameters-in-each-backends-setup_params
+++ a/drivers/block/zram/backend_lzorle.c
@@ -14,6 +14,14 @@ static void lzorle_release_params(struct
 
 static int lzorle_setup_params(struct zcomp_params *params)
 {
+	if (params->dict_sz) {
+		pr_err("dictionary is not supported\n");
+		return -EOPNOTSUPP;
+	}
+	if (params->level != ZCOMP_PARAM_NOT_SET) {
+		pr_err("compression level is not supported\n");
+		return -EOPNOTSUPP;
+	}
 	return 0;
 }
 
--- a/drivers/block/zram/backend_zstd.c~zram-validate-parameters-in-each-backends-setup_params
+++ a/drivers/block/zram/backend_zstd.c
@@ -60,8 +60,13 @@ static int zstd_setup_params(struct zcom
 		return -ENOMEM;
 
 	params->drv_data = zp;
-	if (params->level == ZCOMP_PARAM_NOT_SET)
+	if (params->level == ZCOMP_PARAM_NOT_SET) {
 		params->level = zstd_default_clevel();
+	} else if (params->level < zstd_min_clevel() ||
+		   params->level > zstd_max_clevel()) {
+		pr_err("invalid compression level %d\n", params->level);
+		goto error;
+	}
 
 	zp->cprm = zstd_get_params(params->level, PAGE_SIZE);
 
_

Patches currently in -mm which might be from [email protected] are

zram-do-not-release-zstd-global-params-from-error-paths.patch
zram-reject-zero-size-dictionary.patch
zram-add-pr_fmt-to-backend-files.patch
zram-validate-parameters-in-each-backends-setup_params.patch
zram-reset-per-priority-params-when-changing-algorithm-before-init.patch