The patch titled
Subject: zram: fix pool name truncation
has been added to the -mm tree. Its filename is
zram-fix-pool-name-truncation.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/zram-fix-pool-name-truncation.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/zram-fix-pool-name-truncation.patch
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------------------------------------------------------
From: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Subject: zram: fix pool name truncation
zram_meta_alloc() constructs a pool name for zs_create_pool() call as
snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);
However, it defines pool name buffer to be only 8 bytes long (minus
trailing zero), which means that we can have only 1000 pool names: zram0
-- zram999.
With CONFIG_ZSMALLOC_STAT enabled an attempt to create a device zram1000
can fail if device zram100 already exists, because snprintf() will
truncate new pool name to zram100 and pass it debugfs_create_dir(),
causing:
debugfs dir <zram100> creation failed
zram: Error creating memory pool
... and so on.
Fix it by passing zram->disk->disk_name to zram_meta_alloc() instead of
divice_id. We construct zram%d name earlier and keep it as a ->disk_name,
no need to snprintf() it again.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff -puN drivers/block/zram/zram_drv.c~zram-fix-pool-name-truncation drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-fix-pool-name-truncation
+++ a/drivers/block/zram/zram_drv.c
@@ -496,10 +496,9 @@ static void zram_meta_free(struct zram_m
kfree(meta);
}
-static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize)
+static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
{
size_t num_pages;
- char pool_name[8];
struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
if (!meta)
@@ -512,7 +511,6 @@ static struct zram_meta *zram_meta_alloc
goto out_error;
}
- snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);
meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM);
if (!meta->mem_pool) {
pr_err("Error creating memory pool\n");
@@ -1031,7 +1029,7 @@ static ssize_t disksize_store(struct dev
return -EINVAL;
disksize = PAGE_ALIGN(disksize);
- meta = zram_meta_alloc(zram->disk->first_minor, disksize);
+ meta = zram_meta_alloc(zram->disk->disk_name, disksize);
if (!meta)
return -ENOMEM;
_
Patches currently in -mm which might be from sergey.senozhatsky@xxxxxxxxx are
zram-fix-pool-name-truncation.patch
mm-slab_common-allow-null-cache-pointer-in-kmem_cache_destroy.patch
mm-mempool-allow-null-pool-pointer-in-mempool_destroy.patch
mm-dmapool-allow-null-pool-pointer-in-dma_pool_destroy.patch
zsmalloc-drop-unused-variable-nr_to_migrate.patch
zsmalloc-always-keep-per-class-stats.patch
zsmalloc-introduce-zs_can_compact-function.patch
zsmalloc-cosmetic-compaction-code-adjustments.patch
zsmalloc-zram-introduce-zs_pool_stats-api.patch
zsmalloc-account-the-number-of-compacted-pages.patch
zsmalloc-use-shrinker-to-trigger-auto-compaction.patch
zsmalloc-partial-page-ordering-within-a-fullness_list.patch
zsmalloc-consider-zs_almost_full-as-migrate-source.patch
zsmalloc-use-class-pages_per_zspage.patch
zsmalloc-do-not-take-class-lock-in-zs_shrinker_count.patch
zsmalloc-remove-null-check-from-destroy_handle_cache.patch
zram-unify-error-reporting.patch
checkpatch-add-some-foo_destroy-functions-to-needless_if-tests.patch
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