mbox series

[bpf,v2,0/2] x86/bpf: Fixes for the BPF JIT with retbleed=stuff

Message ID 20240401172157.5717-1-ubizjak@gmail.com (mailing list archive)
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Series x86/bpf: Fixes for the BPF JIT with retbleed=stuff | expand

Message

Uros Bizjak April 1, 2024, 5:18 p.m. UTC 
Fixes two issues that cause kernels panic when using the BPF JIT with
the call depth tracking / stuffing mitigation for Skylake processors
(`retbleed=stuff`). Both issues can be triggered by running simple
BPF programs (e.g. running the test suite should trigger both).

The first (resubmit) fixes a trivial issue related to calculating the
destination IP for call instructions with call depth tracking.

The second is related to using the correct IP for relocations, related
to the recently introduced %rip-relative addressing for PER_CPU_VAR.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
---
v2:
  Simplify calculation of "ip".
  Explicitly list offending commit in the commit message.

Joan Bruguera Micó (1):
  x86/bpf: Fix IP for relocating call depth accounting

Uros Bizjak (1):
  x86/bpf: Fix IP after emitting call depth accounting

 arch/x86/include/asm/alternative.h |  4 ++--
 arch/x86/kernel/callthunks.c       |  4 ++--
 arch/x86/net/bpf_jit_comp.c        | 19 ++++++++-----------
 3 files changed, 12 insertions(+), 15 deletions(-)