CVE-2022-49522 mmc: jz4740: Apply DMA engine limits to maximum segment size

Medium 5.5 Published 26 Feb 2025 Updated 11 May 2026

A missing DMA segment size limit in the Linux kernel MMC driver can trigger kernel warnings and potential instability when DMA API debugging is enabled.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2022-49522?

CVE-2022-49522 is a medium-severity denial of service vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

mmc: jz4740: Apply DMA engine limits to maximum segment size

Do what is done in other DMA-enabled MMC host drivers (cf. host/mmci.c) and limit the maximum segment size based on the DMA engine's capabilities. This is needed to avoid warnings like the following with CONFIG_DMA_API_DEBUG=y.

------------[ cut here ]------------ WARNING: CPU: 0 PID: 21 at kernel/dma/debug.c:1162 debug_dma_map_sg+0x2f4/0x39c DMA-API: jz4780-dma 13420000.dma-controller: mapping sg segment longer than device claims to support [len=98304] [max=65536] CPU: 0 PID: 21 Comm: kworker/0:1H Not tainted 5.18.0-rc1 #19 Workqueue: kblockd blk_mq_run_work_fn Stack : 81575aec 00000004 80620000 80620000 80620000 805e7358 00000009 801537ac 814c832c 806276e3 806e34b4 80620000 81575aec 00000001 81575ab8 09291444 00000000 00000000 805e7358 81575958 ffffffea 8157596c 00000000 636f6c62 6220646b 80387a70 0000000f 6d5f6b6c 80620000 00000000 81575ba4 00000009 805e170c 80896640 00000001 00010000 00000000 00000000 00006098 806e0000 ... Call Trace: [<80107670>] show_stack+0x84/0x120 [<80528cd8>] __warn+0xb8/0xec [<80528d78>] warn_slowpath_fmt+0x6c/0xb8 [<8016f1d4>] debug_dma_map_sg+0x2f4/0x39c [<80169d4c>] __dma_map_sg_attrs+0xf0/0x118 [<8016a27c>] dma_map_sg_attrs+0x14/0x28 [<804f66b4>] jz4740_mmc_prepare_dma_data+0x74/0xa4 [<804f6714>] jz4740_mmc_pre_request+0x30/0x54 [<804f4ff4>] mmc_blk_mq_issue_rq+0x6e0/0x7bc [<804f5590>] mmc_mq_queue_rq+0x220/0x2d4 [<8038b2c0>] blk_mq_dispatch_rq_list+0x480/0x664 [<80391040>] blk_mq_do_dispatch_sched+0x2dc/0x370 [<80391468>] __blk_mq_sched_dispatch_requests+0xec/0x164 [<80391540>] blk_mq_sched_dispatch_requests+0x44/0x94 [<80387900>] __blk_mq_run_hw_queue+0xb0/0xcc [<80134c14>] process_one_work+0x1b8/0x264 [<80134ff8>] worker_thread+0x2ec/0x3b8 [<8013b13c>] kthread+0x104/0x10c [<80101dcc>] ret_from_kernel_thread+0x14/0x1c

---[ end trace 0000000000000000 ]---

Which versions are affected by CVE-2022-49522?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2022-49522?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2022-49522 being exploited?

There is no known exploitation of CVE-2022-49522 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as DEBIAN-CVE-2022-49522, GHSA-gqc7-5rv7-5pv6, UBUNTU-CVE-2022-49522.