Description
In the Linux kernel, the following vulnerability has been resolved: LoongArch: BPF: Fix off-by-one error in build_prologue() Vincent reported that running BPF progs with tailcalls on LoongArch causes kernel hard lockup. Debugging the issues shows that the JITed image missing a jirl instruction at the end of the epilogue. There are two passes in JIT compiling, the first pass set the flags and the second pass generates JIT code based on those flags. With BPF progs mixing bpf2bpf and tailcalls, build_prologue() generates N insns in the first pass and then generates N+1 insns in the second pass. This makes epilogue_offset off by one and we will jump to some unexpected insn and cause lockup. Fix this by inserting a nop insn.
Affected products
linux: linux kernel
References5
- git.kernel.org/stable/c/205a2182c51ffebaef54d643e3745e720cded08b Patch
- git.kernel.org/stable/c/48b904de2408af5f936f0e03f48dfcddeab58aa0 Patch
- git.kernel.org/stable/c/7e2586991e36663c9bc48c828b83eab180ad30a9 Patch
- git.kernel.org/stable/c/b3ffad2f02db4aace6799fe0049508b8925eae45 Patch
- git.kernel.org/stable/c/c74d95a5679741ef428974ab788f5b0758dc78ae Patch
Metrics
- CVSS 3.1
-
5.5
MEDIUM
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 21 · as of 7 November 2026
- CWE
- CWE-193
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