CVE-2026-92485

Summary

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix WARNING in bpf_tracing_link_release

The trampoline could be corrupted by the blindly 'tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX' in verifier.

  1. A fexit attached to a tail_call_reachable prog. 'tr->flags' became 'BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_TAIL_CALL_CTX'. And, the trampoline would poke the target prog's nop insn using jmp insn instead of call insn.
  2. Another fexit loaded with the same tail_call_reachable prog target. 'tr->flags' became 'BPF_TRAMP_F_TAIL_CALL_CTX'.
  3. Close the first fexit link. Due to no BPF_TRAMP_F_CALL_ORIG in 'tr->flags', the trampoline will fail to restore the prog's nop insn using call insn.

[ 3.410719] WARNING: kernel/bpf/syscall.c:3551 at bpf_tracing_link_release+0x53/0x60, CPU#1: test_progs/98 … [ 3.428793] bpf_link_free+0x58/0x130 [ 3.429293] bpf_link_release+0x23/0x30

Fix the warning by updating 'tr->flags' with '|=' and lock.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux2b5dcb31a19a2e0acd869b12c9db9b2d696ef544 < 48a0209d8da0d90a7b0a0db19d1ff88027b13781affected
LinuxLinux2b5dcb31a19a2e0acd869b12c9db9b2d696ef544 < 61aaa8782bec59ecffd22e030f54ef9351bcabf9affected
LinuxLinux605c8d8f9966fcd2f0b858fabebe416fc83f2209affected
LinuxLinux028480eaf2a1401e914a1fa1a4a21d877cf0ae30affected
LinuxLinux8f873cc3f67f2257493063e57d0caf07ef889ee9affected
LinuxLinux6.1.72 < 6.2affected
LinuxLinux6.5.12 < 6.6affected
LinuxLinux6.6.2 < 6.7affected
LinuxLinux6.7affected
LinuxLinux0 < 6.7unaffected
LinuxLinux7.2.6 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References