From: Joan Bruguera Micó <joanbrugueram@xxxxxxxxx>
Adjust the IP passed to `emit_patch` so it calculates the correct offset
for the CALL instruction if `x86_call_depth_emit_accounting` emits code.
Otherwise we will skip some instructions and most likely crash.
Fixes: b2e9dfe54be4 ("x86/bpf: Emit call depth accounting if required")
Link: https://lore.kernel.org/lkml/20230105214922.250473-1-joanbrugueram@xxxxxxxxx/
Signed-off-by: Joan Bruguera Micó <joanbrugueram@xxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
---
arch/x86/net/bpf_jit_comp.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index a7ba8e178645..09f7dc9d4d65 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -479,9 +479,10 @@ static int emit_call(u8 **pprog, void *func, void *ip)
static int emit_rsb_call(u8 **pprog, void *func, void *ip)
{
+ void *adjusted_ip;
OPTIMIZER_HIDE_VAR(func);
- x86_call_depth_emit_accounting(pprog, func);
- return emit_patch(pprog, func, ip, 0xE8);
+ adjusted_ip = ip + x86_call_depth_emit_accounting(pprog, func);
+ return emit_patch(pprog, func, adjusted_ip, 0xE8);
}
static int emit_jump(u8 **pprog, void *func, void *ip)
--
2.44.0
