In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
serial: qcom_geni: fix kfifo underflow when flush precedes DMA completion IRQ<\/p>\n
When uart_flush_buffer() runs before the DMA completion IRQ is delivered,
\nthe following race can occur (all steps serialized by uart_port_lock):<\/p>\n
1. DMA starts: tx_remaining = N, kfifo contains N bytes
\n 2. DMA completes in hardware; IRQ is pending but not yet delivered
\n 3. uart_flush_buffer() acquires the port lock and calls kfifo_reset(),
\n making kfifo_len() = 0 while tx_remaining remains N
\n 4. uart_flush_buffer() releases the port lock
\n 5. DMA IRQ fires; handle_tx_dma() acquires the port lock and calls
\n uart_xmit_advance(uport, tx_remaining) on an empty kfifo<\/p>\n
uart_xmit_advance() increments kfifo->out by tx_remaining. Since
\nkfifo_reset() already set both in and out to 0, out wraps past in,
\ncausing kfifo_len() to return UART_XMIT_SIZE – tx_remaining. The next
\nstart_tx_dma() call then submits a DMA transfer of stale buffer data.<\/p>\n
Fix this by snapshotting kfifo_len() at the start of handle_tx_dma()
\nand skipping uart_xmit_advance() when fifo_len < tx_remaining, which
\nindicates the kfifo was reset by a preceding flush.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
serial: qcom_geni: fix kfifo underflow when flush precedes DMA completion IRQ<\/p>\n
When uart_flush_buffer() runs before the DMA complet<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-14937","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/14937","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14937"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14937"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14937"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}