queue-6.6/x86-bpf-fix-ip-after-emitting-call-depth-accounting.patch

   1 From 9d98aa088386aee3db1b7b60b800c0fde0654a4a Mon Sep 17 00:00:00 2001
   2 From: Uros Bizjak <ubizjak@gmail.com>
   3 Date: Mon, 1 Apr 2024 20:55:29 +0200
   4 Subject: x86/bpf: Fix IP after emitting call depth accounting
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   8
   9 From: Uros Bizjak <ubizjak@gmail.com>
  10
  11 commit 9d98aa088386aee3db1b7b60b800c0fde0654a4a upstream.
  12
  13 Adjust the IP passed to `emit_patch` so it calculates the correct offset
  14 for the CALL instruction if `x86_call_depth_emit_accounting` emits code.
  15 Otherwise we will skip some instructions and most likely crash.
  16
  17 Fixes: b2e9dfe54be4 ("x86/bpf: Emit call depth accounting if required")
  18 Link: https://lore.kernel.org/lkml/20230105214922.250473-1-joanbrugueram@gmail.com/
  19 Co-developed-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
  20 Signed-off-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
  21 Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
  22 Cc: Alexei Starovoitov <ast@kernel.org>
  23 Cc: Daniel Borkmann <daniel@iogearbox.net>
  24 Link: https://lore.kernel.org/r/20240401185821.224068-2-ubizjak@gmail.com
  25 Signed-off-by: Alexei Starovoitov <ast@kernel.org>
  26 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  27 ---
  28  arch/x86/net/bpf_jit_comp.c |    2 +-
  29  1 file changed, 1 insertion(+), 1 deletion(-)
  30
  31 --- a/arch/x86/net/bpf_jit_comp.c
  32 +++ b/arch/x86/net/bpf_jit_comp.c
  33 @@ -344,7 +344,7 @@ static int emit_call(u8 **pprog, void *f
  34  static int emit_rsb_call(u8 **pprog, void *func, void *ip)
  35  {
  36         OPTIMIZER_HIDE_VAR(func);
  37 -       x86_call_depth_emit_accounting(pprog, func);
  38 +       ip += x86_call_depth_emit_accounting(pprog, func);
  39         return emit_patch(pprog, func, ip, 0xE8);
  40  }
  41