Bug 2420331 (CVE-2023-53848)
| Summary: | CVE-2023-53848 kernel: md/raid5-cache: fix a deadlock in r5l_exit_log() | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | rhel-process-autobot, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A deadlock vulnerability was found in the md RAID5 cache (r5l) subsystem in the Linux kernel. In r5l_exit_log(), flush_work() is called while holding reconfig_mutex, which waits for disable_writeback_work to complete. However, r5c_disable_writeback_async() calls wait_event() which requires conf->log to be NULL, but that only happens after flush_work() returns, creating a deadlock.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
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In the Linux kernel, the following vulnerability has been resolved: md/raid5-cache: fix a deadlock in r5l_exit_log() Commit b13015af94cf ("md/raid5-cache: Clear conf->log after finishing work") introduce a new problem: // caller hold reconfig_mutex r5l_exit_log flush_work(&log->disable_writeback_work) r5c_disable_writeback_async wait_event /* * conf->log is not NULL, and mddev_trylock() * will fail, wait_event() can never pass. */ conf->log = NULL Fix this problem by setting 'config->log' to NULL before wake_up() as it used to be, so that wait_event() from r5c_disable_writeback_async() can exist. In the meantime, move forward md_unregister_thread() so that null-ptr-deref this commit fixed can still be fixed.