kernel/linux.git/drivers/block/null_blk, branch v6.19.11

null_blk: fix kmemleak by releasing references to fault configfs items

2026-01-13T14:24:37+00:00

When CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION is enabled, the null-blk driver sets up fault injection support by creating the timeout_inject, requeue_inject, and init_hctx_fault_inject configfs items as children of the top-level nullbX configfs group. However, when the nullbX device is removed, the references taken to these fault-config configfs items are not released. As a result, kmemleak reports a memory leak, for example: unreferenced object 0xc00000021ff25c40 (size 32): comm "mkdir", pid 10665, jiffies 4322121578 hex dump (first 32 bytes): 69 6e 69 74 5f 68 63 74 78 5f 66 61 75 6c 74 5f init_hctx_fault_ 69 6e 6a 65 63 74 00 88 00 00 00 00 00 00 00 00 inject.......... backtrace (crc 1a018c86): __kmalloc_node_track_caller_noprof+0x494/0xbd8 kvasprintf+0x74/0xf4 config_item_set_name+0xf0/0x104 config_group_init_type_name+0x48/0xfc fault_config_init+0x48/0xf0 0xc0080000180559e4 configfs_mkdir+0x304/0x814 vfs_mkdir+0x49c/0x604 do_mkdirat+0x314/0x3d0 sys_mkdir+0xa0/0xd8 system_call_exception+0x1b0/0x4f0 system_call_vectored_common+0x15c/0x2ec Fix this by explicitly releasing the references to the fault-config configfs items when dropping the reference to the top-level nullbX configfs group. Cc: stable@vger.kernel.org Reviewed-by: Chaitanya Kulkarni Fixes: bb4c19e030f4 ("block: null_blk: make fault-injection dynamically configurable per device") Signed-off-by: Nilay Shroff Signed-off-by: Jens Axboe

null_blk: fix zone read length beyond write pointer

2025-11-12T17:02:56+00:00

Fix up the divisor calculating the number of zone sectors being read and handle a read that straddles the zone write pointer. The length is rounded up a sector boundary, so be sure to truncate any excess bytes off to avoid copying past the data segment. Fixes: 3451cf34f51bb70 ("null_blk: allow byte aligned memory offsets") Signed-off-by: Keith Busch Tested-by: Bart van Assche Signed-off-by: Jens Axboe

null_blk: allow byte aligned memory offsets

2025-11-06T23:28:55+00:00

Allowing byte aligned memory provides a nice testing ground for direct-io. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Damien Le Moal Reviewed-by: Chaitanya Kulkarni Tested-by: Hans Holmberg Signed-off-by: Jens Axboe

null_blk: single kmap per bio segment

2025-11-06T23:27:36+00:00

Rather than kmap the the request bio segment for each sector, do the mapping just once. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Damien Le Moal Reviewed-by: Chaitanya Kulkarni Tested-by: Hans Holmberg Signed-off-by: Jens Axboe

null_blk: consistently use blk_status_t

2025-11-06T23:27:21+00:00

No need to mix errno and blk_status_t error types. Just use the standard block layer type. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Damien Le Moal Reviewed-by: Chaitanya Kulkarni Tested-by: Hans Holmberg Signed-off-by: Jens Axboe

null_blk: simplify copy_from_nullb

2025-11-06T23:27:21+00:00

It always returns success, so the code that saves the errors status, but proceeds without checking it looks a bit odd. Clean this up. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Damien Le Moal Reviewed-by: Chaitanya Kulkarni Tested-by: Hans Holmberg Signed-off-by: Jens Axboe

block: introduce disk_report_zone()

2025-11-05T15:07:21+00:00

Commit b76b840fd933 ("dm: Fix dm-zoned-reclaim zone write pointer alignment") introduced an indirect call for the callback function of a report zones executed with blkdev_report_zones(). This is necessary so that the function disk_zone_wplug_sync_wp_offset() can be called to refresh a zone write plug zone write pointer offset after a write error. However, this solution makes following the path of a zone information harder to understand. Clean this up by introducing the new blk_report_zones_args structure to define a zone report callback and its private data and introduce the helper function disk_report_zone() which calls both disk_zone_wplug_sync_wp_offset() and the zone report user callback function for all zones of a zone report. This helper function must be called by all block device drivers that implement the report zones block operation in order to correctly report a zone information. All block device drivers supporting the report_zones block operation are updated to use this new scheme. Signed-off-by: Damien Le Moal Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Chaitanya Kulkarni Reviewed-by: Hannes Reinecke Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe

null_blk: Fix the description of the cache_size module argument

2025-09-08T14:06:10+00:00

When executing modinfo null_blk, there is an error in the description of module parameter mbps, and the output information of cache_size is incomplete.The output of modinfo before and after applying this patch is as follows: Before: [...] parm: cache_size:ulong [...] parm: mbps:Cache size in MiB for memory-backed device. Default: 0 (none) (uint) [...] After: [...] parm: cache_size:Cache size in MiB for memory-backed device. Default: 0 (none) (ulong) [...] parm: mbps:Limit maximum bandwidth (in MiB/s). Default: 0 (no limit) (uint) [...] Fixes: 058efe000b31 ("null_blk: add module parameters for 4 options") Signed-off-by: Genjian Zhang Reviewed-by: Damien Le Moal Signed-off-by: Jens Axboe

null_blk: use memzero_page()

2025-07-10T05:42:08+00:00

memzero_page() is the new name for zero_user(). Link: https://lkml.kernel.org/r/20250612143443.2848197-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Alex Markuze Cc: Christoph Hellwig Cc: Ilya Dryomov Cc: Ira Weiny Cc: Jens Axboe Cc: Xiubo Li Cc: Dan Carpenter Cc: Viacheslav Dubeyko Signed-off-by: Andrew Morton

null_blk: Use strscpy() instead of strscpy_pad() in null_add_dev()

2025-04-11T13:10:46+00:00

blk_mq_alloc_disk() already zero-initializes the destination buffer, making strscpy() sufficient for safely copying the disk's name. The additional NUL-padding performed by strscpy_pad() is unnecessary. If the destination buffer has a fixed length, strscpy() automatically determines its size using sizeof() when the argument is omitted. This makes the explicit size argument unnecessary. The source string is also NUL-terminated and meets the __must_be_cstr() requirement of strscpy(). No functional changes intended. Signed-off-by: Thorsten Blum Reviewed-by: Zhu Yanjun Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20250410154727.883207-1-thorsten.blum@linux.dev Signed-off-by: Jens Axboe