https://cve.radiocsirt.org Contains only the most 10 recent entries. http://www.rssboard.org/rss-specification python-feedgen en Mon, 05 Oct 2026 13:48:48 +0000 https://cve.radiocsirt.org/vuln/cve-2021-46921 <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>locking/qrwlock: Fix ordering in queued_write_lock_slowpath()</p> <p>While this code is executed with the wait_lock held, a reader can acquire the lock without holding wait_lock. The writer side loops checking the value with the atomic_cond_read_acquire(), but only truly acquires the lock when the compare-and-exchange is completed successfully which isn’t ordered. This exposes the window between the acquire and the cmpxchg to an A-B-A problem which allows reads following the lock acquisition to observe values speculatively before the write lock is truly acquired.</p> <p>We&#39;ve seen a problem in epoll where the reader does a xchg while holding the read lock, but the writer can see a value change out from under it.</p> <p>Writer | Reader -------------------------------------------------------------------------------- ep_scan_ready_list() | |- write_lock_irq() | |- queued_write_lock_slowpath() | |- atomic_cond_read_acquire() | | read_lock_irqsave(&amp;ep-&gt;lock, flags); --&gt; (observes value before unlock) | chain_epi_lockless() | | epi-&gt;next = xchg(&amp;ep-&gt;ovflist, epi); | | read_unlock_irqrestore(&amp;ep-&gt;lock, flags); | | | atomic_cmpxchg_relaxed() | |-- READ_ONCE(ep-&gt;ovflist); |</p> <p>A core can order…</p> <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>locking/qrwlock: Fix ordering in queued_write_lock_slowpath()</p> <p>While this code is executed with the wait_lock held, a reader can acquire the lock without holding wait_lock. The writer side loops checking the value with the atomic_cond_read_acquire(), but only truly acquires the lock when the compare-and-exchange is completed successfully which isn’t ordered. This exposes the window between the acquire and the cmpxchg to an A-B-A problem which allows reads following the lock acquisition to observe values speculatively before the write lock is truly acquired.</p> <p>We&#39;ve seen a problem in epoll where the reader does a xchg while holding the read lock, but the writer can see a value change out from under it.</p> <p>Writer | Reader -------------------------------------------------------------------------------- ep_scan_ready_list() | |- write_lock_irq() | |- queued_write_lock_slowpath() | |- atomic_cond_read_acquire() | | read_lock_irqsave(&amp;ep-&gt;lock, flags); --&gt; (observes value before unlock) | chain_epi_lockless() | | epi-&gt;next = xchg(&amp;ep-&gt;ovflist, epi); | | read_unlock_irqrestore(&amp;ep-&gt;lock, flags); | | | atomic_cmpxchg_relaxed() | |-- READ_ONCE(ep-&gt;ovflist); |</p> <p>A core can order…</p> https://cve.radiocsirt.org/vuln/cve-2021-46921