206 lines
11 KiB
JSON
206 lines
11 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-2026-43244",
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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": "2026-05-01T14:12:55.995Z",
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"datePublished": "2026-05-06T11:28:36.946Z",
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"dateUpdated": "2026-10-30T12:25:15.565Z"
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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": "2026-10-30T12:25:15.565Z"
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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\nkcm: fix zero-frag skb in frag_list on partial sendmsg error\n\nSyzkaller reported a warning in kcm_write_msgs() when processing a\nmessage with a zero-fragment skb in the frag_list.\n\nWhen kcm_sendmsg() fills MAX_SKB_FRAGS fragments in the current skb,\nit allocates a new skb (tskb) and links it into the frag_list before\ncopying data. If the copy subsequently fails (e.g. -EFAULT from\nuser memory), tskb remains in the frag_list with zero fragments:\n\n head skb (msg being assembled, NOT yet in sk_write_queue)\n +-----------+\n | frags[17] | (MAX_SKB_FRAGS, all filled with data)\n | frag_list-+--> tskb\n +-----------+ +----------+\n | frags[0] | (empty! copy failed before filling)\n +----------+\n\nFor SOCK_SEQPACKET with partial data already copied, the error path\nsaves this message via partial_message for later completion. For\nSOCK_SEQPACKET, sock_write_iter() automatically sets MSG_EOR, so a\nsubsequent zero-length write(fd, NULL, 0) completes the message and\nqueues it to sk_write_queue. kcm_write_msgs() then walks the\nfrag_list and hits:\n\n WARN_ON(!skb_shinfo(skb)->nr_frags)\n\nTCP has a similar pattern where skbs are enqueued before data copy\nand cleaned up on failure via tcp_remove_empty_skb(). KCM was\nmissing the equivalent cleanup.\n\nFix this by tracking the predecessor skb (frag_prev) when allocating\na new frag_list entry. On error, if the tail skb has zero frags,\nuse frag_prev to unlink and free it in O(1) without walking the\nsingly-linked frag_list. frag_prev is safe to dereference because\nthe entire message chain is only held locally (or in kcm->seq_skb)\nand is not added to sk_write_queue until MSG_EOR, so the send path\ncannot free it underneath us.\n\nAlso change the WARN_ON to WARN_ON_ONCE to avoid flooding the log\nif the condition is somehow hit repeatedly.\n\nThere are currently no KCM selftests in the kernel tree; a simple\nreproducer is available at [1].\n\n[1] https://gist.github.com/mrpre/a94d431c757e8d6f168f4dd1a3749daa"
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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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"net/kcm/kcmsock.c"
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],
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"versions": [
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{
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"version": "ab7ac4eb9832e32a09f4e8042705484d2fb0aad3",
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"lessThan": "d6dcbcc8d630d14e9651fe93a9386b35f4dcfd56",
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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": "ab7ac4eb9832e32a09f4e8042705484d2fb0aad3",
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"lessThan": "6f129a251c2795ba55dd5cc1fdf7e0af3098d848",
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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": "ab7ac4eb9832e32a09f4e8042705484d2fb0aad3",
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"lessThan": "9ea3671d70ee07480d80bebe86696397c4e99fb7",
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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": "ab7ac4eb9832e32a09f4e8042705484d2fb0aad3",
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"lessThan": "b1e3edf688a88c1a3ac41657055d9c136a08cd25",
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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": "ab7ac4eb9832e32a09f4e8042705484d2fb0aad3",
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"lessThan": "7af58f76e4b404a74c836881a845e6652db8a09f",
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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": "ab7ac4eb9832e32a09f4e8042705484d2fb0aad3",
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"lessThan": "ca220141fa8ebae09765a242076b2b77338106b0",
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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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"net/kcm/kcmsock.c"
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],
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"versions": [
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{
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"version": "4.6",
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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": "4.6",
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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": "6.1.191",
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"lessThanOrEqual": "6.1.*",
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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": "6.6.160",
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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": "6.12.75",
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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": "6.18.16",
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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": "6.19.6",
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"lessThanOrEqual": "6.19.*",
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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",
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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": "4.6",
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"versionEndExcluding": "6.1.191"
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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": "4.6",
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"versionEndExcluding": "6.6.160"
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},
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{
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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "4.6",
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"versionEndExcluding": "6.12.75"
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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": "4.6",
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"versionEndExcluding": "6.18.16"
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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": "4.6",
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"versionEndExcluding": "6.19.6"
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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": "4.6",
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"versionEndExcluding": "7.0"
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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/d6dcbcc8d630d14e9651fe93a9386b35f4dcfd56"
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},
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{
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"url": "https://git.kernel.org/stable/c/6f129a251c2795ba55dd5cc1fdf7e0af3098d848"
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},
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{
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"url": "https://git.kernel.org/stable/c/9ea3671d70ee07480d80bebe86696397c4e99fb7"
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},
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{
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"url": "https://git.kernel.org/stable/c/b1e3edf688a88c1a3ac41657055d9c136a08cd25"
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},
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{
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"url": "https://git.kernel.org/stable/c/7af58f76e4b404a74c836881a845e6652db8a09f"
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},
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{
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"url": "https://git.kernel.org/stable/c/ca220141fa8ebae09765a242076b2b77338106b0"
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}
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],
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"title": "kcm: fix zero-frag skb in frag_list on partial sendmsg error",
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"x_generator": {
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"engine": "bippy-1.2.0"
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}
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} |