201 lines
12 KiB
JSON
201 lines
12 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-63883",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-07-19T07:54:57.018Z",
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"datePublished": "2026-07-19T14:54:56.356Z",
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"dateUpdated": "2026-08-05T12:36:52.126Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-08-05T12:36:52.126Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nserial: qcom_geni: fix kfifo underflow when flush precedes DMA completion IRQ\n\nWhen uart_flush_buffer() runs before the DMA completion IRQ is delivered,\nthe following race can occur (all steps serialized by uart_port_lock):\n\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\n\nuart_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.\n\nFix 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."
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L",
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"baseScore": 7.3,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The bug is reachable only through local TTY syscalls (open/write/ioctl/close) on Qualcomm GENI high-speed UART device nodes (e.g. /dev/ttyHS*); it is not triggered by remote network packets or physical bus manipulation alone.\nAC:L - An attacker who can open the port controls both sides of the race by writing to start DMA TX and immediately issuing TCFLSH/TCOFLUSH (or closing the port) to call uart_flush_buffer() before the DMA completion IRQ runs, and can repeat until the window is hit.\nPR:L - Exploitation requires only the ability to open and ioctl the UART TTY device (typically dialout-group membership or equivalent service access on Qualcomm Android/automotive/embedded platforms), not init-namespace root or capabilities obtainable only outside user namespaces.\nUI:N - Triggering the flush-vs-DMA-IRQ race requires no victim interaction beyond the attacker's own writes and flush/close operations on the serial port.\nS:U - Impact is confined to kernel serial-driver state and data transmitted on the local UART; it does not cross VM, container, or IOMMU security boundaries.\nC:H - The kfifo index underflow corrupts transmit FIFO bookkeeping and can cause a spurious large DMA read of stale xmit_buf contents (up to UART_XMIT_SIZE/PAGE_SIZE), leaking prior sensitive serial traffic (modem/BT/RS485 diagnostics) that should have been discarded by flush.\nI:H - The corrupted kfifo state causes unauthorized transmission of stale or attacker-influenced buffer data over the UART/RS485 line, corrupting the integrity of serial output to connected devices (ECUs, modems, factory controllers) beyond what the attacker legitimately queued.\nA:L - The primary impact is corrupted driver transmit state and spurious/erroneous serial output rather than a demonstrated kernel oops/panic; however, repeated triggering can degrade or disrupt serial communication relied on by connected subsystems."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"drivers/tty/serial/qcom_geni_serial.c"
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],
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"versions": [
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{
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"version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
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"lessThan": "c91ea13375f70f6271a0183445e34e83b8f4d8f7",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
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"lessThan": "b1159dce10b38eb795e4c96cdc4d34b83cec81c5",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
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"lessThan": "654f45a8569f3cd6ff20bd724a18e0cce65893ba",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
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"lessThan": "0d2c41a8b00934ddf8a7c1b4cf72dffa1e629c46",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "2aaa43c7077833301c237684cd7bc9ae5e3dec95",
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"lessThan": "452d6fa37ae9b021f4f6d397dbae077f7296f6f4",
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"status": "affected",
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"versionType": "git"
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"drivers/tty/serial/qcom_geni_serial.c"
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],
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"versions": [
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{
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"version": "6.3",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "6.3",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.6.143",
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"lessThanOrEqual": "6.6.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.12.93",
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"lessThanOrEqual": "6.12.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.35",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.0.12",
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"lessThanOrEqual": "7.0.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.1",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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{
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"nodes": [
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{
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"operator": "OR",
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"negate": false,
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"cpeMatch": [
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.3",
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"versionEndExcluding": "6.6.143"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.3",
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"versionEndExcluding": "6.12.93"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.3",
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"versionEndExcluding": "6.18.35"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.3",
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"versionEndExcluding": "7.0.12"
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},
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{
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"vulnerable": true,
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "6.3",
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"versionEndExcluding": "7.1"
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}
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]
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}
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]
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}
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/c91ea13375f70f6271a0183445e34e83b8f4d8f7"
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},
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{
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"url": "https://git.kernel.org/stable/c/b1159dce10b38eb795e4c96cdc4d34b83cec81c5"
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},
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{
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"url": "https://git.kernel.org/stable/c/654f45a8569f3cd6ff20bd724a18e0cce65893ba"
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},
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{
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"url": "https://git.kernel.org/stable/c/0d2c41a8b00934ddf8a7c1b4cf72dffa1e629c46"
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},
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{
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"url": "https://git.kernel.org/stable/c/452d6fa37ae9b021f4f6d397dbae077f7296f6f4"
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}
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],
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"title": "serial: qcom_geni: fix kfifo underflow when flush precedes DMA completion IRQ",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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}
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}
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} |