Messages in this thread Patch in this message |  | | From | Joan Bruguera <> | Subject | [PATCH] bpf, x86: Fix IP after emitting call depth accounting | Date | Sat, 7 Jan 2023 05:14:56 +0000 |
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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 <joanbrugueram@gmail.com> --- 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 b808be77635e..6e696c6b7018 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -343,9 +343,10 @@ 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 = (u8 *)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) -- 2.39.0
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