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.
Unified · Split
| @@ -496,10 +496,9 @@ static void zram_meta_free(struct zram_meta *meta, u64 disksize) · 495 unmodified lines | ||
| 496 | 496 | kfree(meta); |
| 497 | 497 | } |
| 498 | 498 | |
| 499 | −static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize) | |
| 499 | +static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize) | |
| 500 | 500 | { |
| 501 | 501 | size_t num_pages; |
| 502 | − char pool_name[8]; | |
| 503 | 502 | struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL); |
| 504 | 503 | |
| 505 | 504 | if (!meta) |
| @@ -512,7 +511,6 @@ static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize) · 6 unmodified lines | ||
| 512 | 511 | goto out_error; |
| 513 | 512 | } |
| 514 | 513 | |
| 515 | − snprintf(pool_name, sizeof(pool_name), "zram%d", device_id); | |
| 516 | 514 | meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM); |
| 517 | 515 | if (!meta->mem_pool) { |
| 518 | 516 | pr_err("Error creating memory pool\n"); |
| @@ -1031,7 +1029,7 @@ static ssize_t disksize_store(struct device *dev, · 512 unmodified lines | ||
| 1031 | 1029 | return -EINVAL; |
| 1032 | 1030 | |
| 1033 | 1031 | disksize = PAGE_ALIGN(disksize); |
| 1034 | − meta = zram_meta_alloc(zram->disk->first_minor, disksize); | |
| 1032 | + meta = zram_meta_alloc(zram->disk->disk_name, disksize); | |
| 1035 | 1033 | if (!meta) |
| 1036 | 1034 | return -ENOMEM; |
| 1037 | 1035 | |