From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB58453D0DA for ; Wed, 9 Sep 2026 10:46:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788950763; cv=none; b=T+UQoglkWmF+FPQYYDBBDH5osuvo4HDE9ZRdVi/IU3Ag0+KuZZq+jNH4KS6kiN/tyeQD1TsmAjDdq27aPEDpBUFX6//a0bDqzosp2XMqJuCn6knRxTDaQAxM1vv11A35COb+LWmiHPiuBvifPZISq92Kt1gvkIWsXP5MVkv/wwU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788950763; c=relaxed/simple; bh=UyJQisMfj4TWH0FE7kcTw/zJc3MBhGTXHlFFQjJTVmk=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=q+VGn9r5zD1HzQ8sWMtF495DBv39/EiVtBx7mpJ4Dxx7Ym2LBbZIvV84PmZasLpaAvUbRPU2tJQQDkPpvnN9GqVssKzMcF32CP0RTWieUuIbUD1+CXN3JgyoBCy1T/DA1d/ovHBrlKDWIxwc2bkhYFApS790va2VgDUCXREEgrU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UpO0CZS+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="UpO0CZS+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F19421F00A3E; Wed, 9 Sep 2026 10:46:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788950761; bh=PyNwCLdGLGCqSXAmZXhDhzWcJRUPvDngKZMqD1xMv8c=; h=Subject:To:Cc:From:Date; b=UpO0CZS+D15BrG2XIB5I98MLZYi5ToOZuCgN2R8XSPVh2mP5QUzLPcIy60+8Fz3DE 6wsFjp7d3bM/1huqDEfgNAB1NVcou9OG6sJD6jFiRXiQ7vWkulE9hlca3QLrAwgRcY PFOIFGOxR1izrN+NxVcYBkPklFW3MTR1PY29Q9zw= Subject: FAILED: patch "[PATCH] LoongArch: BPF: Refactor jump offset calculation in tail call" failed to apply to 6.6-stable tree To: yangtiezhu@loongson.cn,chenhuacai@loongson.cn Cc: From: Date: Wed, 09 Sep 2026 12:39:34 +0200 Message-ID: <2026090934-greyhound-constant-1448@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 37d545d12f21c4d50612ecaebd7ae1e5bf91b2d8 # git commit -s git send-email --to '' --in-reply-to '2026090934-greyhound-constant-1448@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 37d545d12f21c4d50612ecaebd7ae1e5bf91b2d8 Mon Sep 17 00:00:00 2001 From: Tiezhu Yang Date: Mon, 17 Aug 2026 22:07:23 +0800 Subject: [PATCH] LoongArch: BPF: Refactor jump offset calculation in tail call The old macro-based jmp_offset calculation derives the jump distance from a stale prior-pass code stride, which can lead to wrong branch offsets and soft lockups under extra JIT passes. Fix this by calculating the offset directly on the absolute target: "ctx->offset[insn + 1] - ctx->idx". To avoid a false 16-bit range check abort during size estimation, add a "ctx->image == NULL" guard to inject a safe dummy offset. Cc: stable@vger.kernel.org Fixes: cd39d9e6b7e4 ("LoongArch: BPF: Fix jump offset calculation in tailcall") Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index fd5f8c4e5360..846d652b0d22 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -290,17 +290,13 @@ bool bpf_jit_supports_far_kfunc_call(void) static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn) { - int off, tc_ninsn = 0; + int off, jmp_offset; int tcc_ptr_off = BPF_TAIL_CALL_CNT_PTR_STACK_OFF(ctx->stack_size); u8 a1 = LOONGARCH_GPR_A1; u8 a2 = LOONGARCH_GPR_A2; u8 t1 = LOONGARCH_GPR_T1; u8 t2 = LOONGARCH_GPR_T2; u8 t3 = LOONGARCH_GPR_T3; - const int idx0 = ctx->idx; - -#define cur_offset (ctx->idx - idx0) -#define jmp_offset (tc_ninsn - (cur_offset)) /* * a0: &ctx @@ -310,12 +306,12 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn) * if (index >= array->map.max_entries) * goto out; */ - tc_ninsn = insn ? ctx->offset[insn+1] - ctx->offset[insn] : ctx->offset[0]; emit_zext_32(ctx, a2, true); off = offsetof(struct bpf_array, map.max_entries); emit_insn(ctx, ldwu, t1, a1, off); /* bgeu $a2, $t1, jmp_offset */ + jmp_offset = ctx->image ? (ctx->offset[insn + 1] - ctx->idx) : 0; if (emit_tailcall_jmp(ctx, BPF_JGE, a2, t1, jmp_offset) < 0) goto toofar; @@ -326,6 +322,7 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn) emit_insn(ctx, ldd, REG_TCC, LOONGARCH_GPR_SP, tcc_ptr_off); emit_insn(ctx, ldd, t3, REG_TCC, 0); emit_insn(ctx, addid, t2, LOONGARCH_GPR_ZERO, MAX_TAIL_CALL_CNT); + jmp_offset = ctx->image ? (ctx->offset[insn + 1] - ctx->idx) : 0; if (emit_tailcall_jmp(ctx, BPF_JSGE, t3, t2, jmp_offset) < 0) goto toofar; @@ -340,6 +337,7 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn) off = offsetof(struct bpf_array, ptrs); emit_insn(ctx, ldd, t2, t2, off); /* beq $t2, $zero, jmp_offset */ + jmp_offset = ctx->image ? (ctx->offset[insn + 1] - ctx->idx) : 0; if (emit_tailcall_jmp(ctx, BPF_JEQ, t2, LOONGARCH_GPR_ZERO, jmp_offset) < 0) goto toofar; @@ -355,8 +353,6 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int insn) toofar: pr_info_once("tail_call: jump too far\n"); return -1; -#undef cur_offset -#undef jmp_offset } static void emit_store_stack_imm64(struct jit_ctx *ctx, int reg, int stack_off, u64 imm64)