Messages in this thread Patch in this message | | | From | Uros Bizjak <> | Subject | [PATCH bpf 1/2] x86/bpf: Fix IP after emitting call depth accounting | Date | Fri, 29 Mar 2024 10:25:07 +0100 |
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From: Joan Bruguera Micó <joanbrugueram@gmail.com>
From: Joan Bruguera Micó <joanbrugueram@gmail.com>
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@gmail.com/ Signed-off-by: Joan Bruguera Micó <joanbrugueram@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> --- 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
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