This is a note to let you know that I've just added the patch titled
x86/bpf: Fix IP after emitting call depth accounting
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-bpf-fix-ip-after-emitting-call-depth-accounting.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9d98aa088386aee3db1b7b60b800c0fde0654a4a Mon Sep 17 00:00:00 2001
From: Uros Bizjak <ubizjak@xxxxxxxxx>
Date: Mon, 1 Apr 2024 20:55:29 +0200
Subject: x86/bpf: Fix IP after emitting call depth accounting
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From: Uros Bizjak <ubizjak@xxxxxxxxx>
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@xxxxxxxxx/
Co-developed-by: Joan Bruguera Micó <joanbrugueram@xxxxxxxxx>
Signed-off-by: Joan Bruguera Micó <joanbrugueram@xxxxxxxxx>
Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240401185821.224068-2-ubizjak@xxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/net/bpf_jit_comp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -466,7 +466,7 @@ static int emit_call(u8 **pprog, void *f
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);
}
Patches currently in stable-queue which might be from ubizjak@xxxxxxxxx are
queue-6.8/x86-bpf-fix-ip-after-emitting-call-depth-accounting.patch
