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SubjectRe: [PATCH] block/genhd: Fix memory leak in error path of __alloc_disk_node()
Looks good,
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>

I think you can also add:

Fixes: 6c71013ecb7e ("block: partition: convert percpu ref")

On Wed, Nov 27, 2019 at 02:40:57AM +0000, Keita Suzuki wrote:
>'disk->part_tbl' is malloced in disk_expand_part_tbl() and should be
>freed before leaving from the error handling cases. However, current code
>does not free this, causing a memory leak. Add disk_replace_part_tbl()
>before freeing 'disk'.
>
>I have tested this by randomly causing failures to the target code,
>and verified on kmemleak that this memory leak does occur.
>
>unreferenced object 0xffff888006dad500 (size 64):
> comm "systemd-udevd", pid 116, jiffies 4294895558 (age 121.716s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [<00000000eec79bf3>] disk_expand_part_tbl+0xab/0x170
> [<00000000624e7d03>] __alloc_disk_node+0xb1/0x1c0
> [<00000000ca3f4185>] 0xffffffffc01b8584
> [<000000006f88a6ee>] do_one_initcall+0x8b/0x2a4
> [<0000000016058199>] do_init_module+0xfd/0x380
> [<00000000b6fde336>] load_module+0x3fae/0x4240
> [<00000000c523d013>] __do_sys_finit_module+0x11a/0x1b0
> [<00000000f07bba26>] do_syscall_64+0x6d/0x1e0
> [<00000000979467fd>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
>Signed-off-by: Keita Suzuki <keitasuzuki.park@sslab.ics.keio.ac.jp>
>---
> block/genhd.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/block/genhd.c b/block/genhd.c
>index ff6268970ddc..8c4b63d7f507 100644
>--- a/block/genhd.c
>+++ b/block/genhd.c
>@@ -1504,6 +1504,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
> */
> seqcount_init(&disk->part0.nr_sects_seq);
> if (hd_ref_init(&disk->part0)) {
>+ disk_replace_part_tbl(disk, NULL);
> hd_free_part(&disk->part0);
> kfree(disk);
> return NULL;
>--
>2.17.1
>

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