In the Linux kernel, the following vulnerability has been resolved:
kcm: annotate data-races around kcm->rx_wait
kcm->rx_psock can be read locklessly in kcm_rfree(). Annotate the read and writes accordingly.
syzbot reported:
BUG: KCSAN: data-race in kcm_rcv_strparser / kcm_rfree
write to 0xffff88810784e3d0 of 1 bytes by task 1823 on cpu 1: reserve_rx_kcm net/kcm/kcmsock.c:283 [inline] kcm_rcv_strparser+0x250/0x3a0 net/kcm/kcmsock.c:363 __strp_recv+0x64c/0xd20 net/strparser/strparser.c:301 strp_recv+0x6d/0x80 net/strparser/strparser.c:335 tcp_read_sock+0x13e/0x5a0 net/ipv4/tcp.c:1703 strp_read_sock net/strparser/strparser.c:358 [inline] do_strp_work net/strparser/strparser.c:406 [inline] strp_work+0xe8/0x180 net/strparser/strparser.c:415 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289 worker_thread+0x618/0xa70 kernel/workqueue.c:2436 kthread+0x1a9/0x1e0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
read to 0xffff88810784e3d0 of 1 bytes by task 17869 on cpu 0: kcm_rfree+0x121/0x220 net/kcm/kcmsock.c:181 skb_release_head_state+0x8e/0x160 net/core/skbuff.c:841 skb_release_all net/core/skbuff.c:852 [inline] __kfree_skb net/core/skbuff.c:868 [inline] kfree_skb_reason+0x5c/0x260 net/core/skbuff.c:891 kfree_skb include/linux/skbuff.h:1216 [inline] kcm_recvmsg+0x226/0x2b0 net/kcm/kcmsock.c:1161 ____sys_recvmsg+0x16c/0x2e0 ___sys_recvmsg net/socket.c:2743 [inline] do_recvmmsg+0x2f1/0x710 net/socket.c:2837 __sys_recvmmsg net/socket.c:2916 [inline] __do_sys_recvmmsg net/socket.c:2939 [inline] __se_sys_recvmmsg net/socket.c:2932 [inline] __x64_sys_recvmmsg+0xde/0x160 net/socket.c:2932 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x01 -> 0x00
Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 17869 Comm: syz-executor.2 Not tainted 6.1.0-rc1-syzkaller-00010-gbb1a1146467a-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade python-perfUpgrade perf-debuginfoUpgrade bpftool-debuginfoUpgrade kernel-toolsUpgrade kernel-tools-debuginfoUpgrade kernel-debuginfoUpgrade kernel-headersUpgrade perfUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-livepatch-5.10.155-138.670Upgrade kernel-develUpgrade kernel-livepatch-4.14.299-223.520Upgrade kernelUpgrade python-perf-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-tools-develUpgrade bpftoolUpgrade kernel-livepatch-5.15.79-51.138 | May 20, 2026 | May 20, 2026 |
| Debian | — | Upgrade linux | Sep 17, 2025 | Sep 17, 2025 |
| Ubuntu | — | Upgrade linux-nvidiaUpgrade linux-gcpUpgrade linux-oracle-5.4Upgrade linux-fipsUpgrade linux-intel-iotgUpgrade linux-gcp-5.4Upgrade linux-aws-5.15Upgrade linux-aws-hweUpgrade linux-gkeUpgrade linux-aws-5.4Upgrade linux-lowlatencyUpgrade linux-ibm-5.4Upgrade linux-xilinx-zynqmpUpgrade linux-riscv-5.15Upgrade linux-oracleUpgrade linux-oracle-5.15Upgrade linux-hwe-5.4Upgrade linux-gcp-fipsUpgrade linux-azure-5.4Upgrade linux-ibmUpgrade linux-azure-fipsUpgrade linuxUpgrade linux-azureUpgrade linux-aws-fipsUpgrade linux-gkeopUpgrade linux-raspiUpgrade linux-azure-5.15Upgrade linux-raspi-5.4Upgrade linux-realtimeUpgrade linux-azure-4.15Upgrade linux-gcp-5.15Upgrade linux-gcp-4.15Upgrade linux-iotUpgrade linux-hweUpgrade linux-hwe-5.15Upgrade linux-lowlatency-hwe-5.15Upgrade linux-kvmUpgrade linux-awsUpgrade linux-bluefieldUpgrade linux-intel-iotg-5.15 | Sep 19, 2025 | Sep 16, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 15, 2025 | Sep 15, 2025 |
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