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x86/bpf: Fix IP after emitting call depth accounting

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commit 9d98aa088386aee3db1b7b60b800c0fde0654a4a upstream.

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/
Co-developed-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Signed-off-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20240401185821.224068-2-ubizjak@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Uros Bizjak 2024-04-01 20:55:29 +02:00 committed by Greg Kroah-Hartman
parent 4d47169ab6
commit 3f9d57c771
1 changed files with 1 additions and 1 deletions
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2
arch/x86/net/bpf_jit_comp.c
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@ -344,7 +344,7 @@ static int emit_call(u8 **pprog, void *func, void *ip)
static int emit_rsb_call(u8 **pprog, void *func, void *ip)
{
OPTIMIZER_HIDE_VAR(func);
x86_call_depth_emit_accounting(pprog, func);
ip += x86_call_depth_emit_accounting(pprog, func);
return emit_patch(pprog, func, ip, 0xE8);
}