# CVE-2022-49607: linux: In the Linux kernel, the following vulnerability has been resolved:  perf/core: Fix data race between perf_event_set_...

CVE-2022-49607 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49607, released February 26, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2022-49607
- Priority: Routine
- CVSS: 4.7 (medium)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 26, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  perf/core: Fix data race between perf_event_set_output() and perf_mmap_close()  Yang Jihing reported a race between perf_event_set_output() and perf_mmap_close():  	CPU1					CPU2  	perf_mmap_close(e2) 	  if (atomic_dec_and_test(&e2->rb->mmap_count)) // 1 - > 0 	    detach_rest = true  						ioctl(e1, IOC_SET_OUTPUT, e2) 						  perf_event_set_output(e1, e2)  	  ... 	  list_for_each_entry_rcu(e, &e2->rb->event_list, rb_entry) 	    ring_buffer_attach(e, NULL); 	    // e1 isn't yet added and 	    // therefore not detached  						    ring_buffer_attach(e1, e2->rb) 						      list_add_rcu(&e1->rb_entry, 								   &e2->rb->event_list)  After this; e1 is attached to an unmapped rb and a subsequent perf_mmap() will loop forever more:  	again: 		mutex_lock(&e->mmap_mutex); 		if (event->rb) { 			... 			if (!atomic_inc_not_zero(&e->rb->mmap_count)) { 				... 				mutex_unlock(&e->mmap_mutex); 				goto again; 			} 		}  The loop in perf_mmap_close() holds e2->mmap_mutex, while the attach in perf_event_set_output() holds e1->mmap_mutex. As such there is no serialization to avoid this race.  Change perf_event_set_output() to take both e1->mmap_mutex and e2->mmap_mutex to alleviate that problem. Additionally, have the loop in perf_mmap() detach the rb directly, this avoids having to wait for the concurrent perf_mmap_close() to get around to doing it to make progress.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.18.16-1 | [DEBIAN-CVE-2022-49607](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49607.md) | Feb 26, 2025 |
| Linux | linux Debian 13.5 (trixie) | 5.18.16-1 | [DEBIAN-CVE-2022-49607](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49607.md) | Feb 26, 2025 |
| Linux | linux Debian 14 | 5.18.16-1 | [DEBIAN-CVE-2022-49607](https://patchblox.com/security/data/fix/linux/debian-cve-2022-49607.md) | Feb 26, 2025 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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