[PATCH] x86 bpf: Fix extable offset calculation
flat view
STALE1932d
LANDED
From: Ravi Bangoria <hidden>
Date: 2021-06-22 11:01:15
Also in:
bpf, lkml
Subsystem:
bpf jit for x86 64-bit, bpf [general] (safe dynamic programs and tools), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Landed in mainline as 328aac5ecd11 on 2021-06-28.
commit 4c5de127598e1 ("bpf: Emit explicit NULL pointer checks
for PROBE_LDX instructions.") is emitting couple of instructions
before actual load. Consider those additional instructions while
calculating extable offset.
Fixes: 4c5de127598e1 ("bpf: Emit explicit NULL pointer checks for PROBE_LDX instructions.")
Signed-off-by: Ravi Bangoria <redacted>
---
arch/x86/net/bpf_jit_comp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 2a2e290fa5d8..231a8178cc11 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c@@ -1297,7 +1297,7 @@ st: if (is_imm8(insn->off)) emit_ldx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off); if (BPF_MODE(insn->code) == BPF_PROBE_MEM) { struct exception_table_entry *ex; - u8 *_insn = image + proglen; + u8 *_insn = image + proglen + (u8)(start_of_ldx - temp); s64 delta; /* populate jmp_offset for JMP above */
--
2.30.2