# CVE-2022-49901: blk-mq: Fix kmemleak in blk_mq_init_allocated_queue

CVE-2022-49901 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49901, released May 1, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-49901
- Priority: Routine
- CVSS: 5.5 (Moderate)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 1, 2025
- Weakness: Missing Release of Memory after Effective Lifetime
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-49901

## Description

In the Linux kernel, the following vulnerability has been resolved:  blk-mq: Fix kmemleak in blk_mq_init_allocated_queue  There is a kmemleak caused by modprobe null_blk.ko  unreferenced object 0xffff8881acb1f000 (size 1024):   comm "modprobe", pid 836, jiffies 4294971190 (age 27.068s)   hex dump (first 32 bytes):     00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .....N..........     ff ff ff ff ff ff ff ff 00 53 99 9e ff ff ff ff  .........S......   backtrace:     [<000000004a10c249>] kmalloc_node_trace+0x22/0x60     [<00000000648f7950>] blk_mq_alloc_and_init_hctx+0x289/0x350     [<00000000af06de0e>] blk_mq_realloc_hw_ctxs+0x2fe/0x3d0     [<00000000e00c1872>] blk_mq_init_allocated_queue+0x48c/0x1440     [<00000000d16b4e68>] __blk_mq_alloc_disk+0xc8/0x1c0     [<00000000d10c98c3>] 0xffffffffc450d69d     [<00000000b9299f48>] 0xffffffffc4538392     [<0000000061c39ed6>] do_one_initcall+0xd0/0x4f0     [<00000000b389383b>] do_init_module+0x1a4/0x680     [<0000000087cf3542>] load_module+0x6249/0x7110     [<00000000beba61b8>] __do_sys_finit_module+0x140/0x200     [<00000000fdcfff51>] do_syscall_64+0x35/0x80     [<000000003c0f1f71>] entry_SYSCALL_64_after_hwframe+0x46/0xb0  That is because q->ma_ops is set to NULL before blk_release_queue is called.  blk_mq_init_queue_data   blk_mq_init_allocated_queue     blk_mq_realloc_hw_ctxs       for (i = 0; i < set->nr_hw_queues; i++) {         old_hctx = xa_load(&q->hctx_table, i);         if (!blk_mq_alloc_and_init_hctx(.., i, ..))		[1]           if (!old_hctx) 	    break;        xa_for_each_start(&q->hctx_table, j, hctx, j)         blk_mq_exit_hctx(q, set, hctx, j); 			[2]      if (!q->nr_hw_queues)					[3]       goto err_hctxs;    err_exit:       q->mq_ops = NULL;			  			[4]    blk_put_queue     blk_release_queue       if (queue_is_mq(q))					[5]         blk_mq_release(q);  [1]: blk_mq_alloc_and_init_hctx failed at i != 0. [2]: The hctxs allocated by [1] are moved to q->unused_hctx_list and will be cleaned up in blk_mq_release. [3]: q->nr_hw_queues is 0. [4]: Set q->mq_ops to NULL. [5]: queue_is_mq returns false due to [4]. And blk_mq_release will not be called. The hctxs in q->unused_hctx_list are leaked.  To fix it, call blk_release_queue in exception path.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.0.8-1 | [DEBIAN-CVE-2022-49901](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49901.md) | May 1, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.0.8-1 | [DEBIAN-CVE-2022-49901](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49901.md) | May 1, 2025 |
| Linux | linux Debian 14 | 6.0.8-1 | [DEBIAN-CVE-2022-49901](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49901.md) | May 1, 2025 |

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