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 EFAA45349C9 for ; Tue, 13 Oct 2026 15:19:17 +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=1791904759; cv=none; b=BqyUiGaj5gB2S/qS3N1VWYq/WND8+vVmu+HcfDjNtEToVZer+jEfQwnVImzVjE5AbxesXiqWEHp/Zv2nmtZsObUkX7eNHmpJ7ZS32raq5r6BI/TSpTtN8blo/ou8xC9I26WDyhnlzguFFOnMfcFH1QxsuqdQpbpNSFZd2hkD0Bg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791904759; c=relaxed/simple; bh=ggWbtHPYSAiZT9lKoZwNuhTB6eGmevstPnx9G1HxWN8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KzRayEHLY2z0lHyRjiW/8QOmcQU/nb6u022aFuMVZLSbXIKQ05v1J6dfd5VabPlXaE4Uh+XD72BvQY7Qt8teY0D15tPnc9XOb2CmJ3kP8dZi1ehxs2GU9LQHxixC6q8wydRwpYpPb5ArMjtrhaOZlQTbapCW7Tydusgtx6L7xow= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iIzOPY3h; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iIzOPY3h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F8811F00898; Tue, 13 Oct 2026 15:19:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791904757; bh=aDTRaLqLD+54pmyctK5IC0LC1Gtcp/4spbMay+hp59Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iIzOPY3h2/9EVCaPga7ziqYWryTWdNZtvDODl5CghRxtaSCOz/bCRQ64tW6ieJkLz Fs33l/+maSbXd2wf1sm+KwDFgAu+ALB6gMOyC7QiSvwWvRkBmV/+5GyVCPTRTm5GG5 AD0LZDJVc0vqN4uazbmY/wb789sgkS5BIE2y9wyhYqloR7PymUm+h93AkG/WEjxQVm GU17ae8kaMJJ9JusO8tq9gtaRE2z90tEv3Fcl+GxC+xPSHhJfwR36NOsDO2iWEylBa C3nCUaibMqyYpXQ/KJEYqdh4jYV8ur3M+VEx6lohfAx4Q6F0B8nyYNbmVfDPlP1Dop WRbRlSHn7vHdQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Wei-Jie Hung , Pu Lehui , Paul Walmsley , Sasha Levin Subject: [PATCH 6.12.y 2/2] riscv: patch: fix handling of bpf-jit execmem addresses Date: Tue, 13 Oct 2026 11:19:15 -0400 Message-ID: <20261013151849.209222-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261013151849.209222-1-sashal@kernel.org> References: <2026101215-envelope-tribute-9992@gregkh> <20261013151849.209222-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Wei-Jie Hung [ Upstream commit a510e1ae8c9030750c2edf7b0bc9b186cd8c7a06 ] Commit 8718e5a3090b ("riscv: patch: skip fixmap mapping when kernel text is already writable") gated the core_kernel_text() branch of patch_map() on CONFIG_STRICT_KERNEL_RWX, and explicitly left the vmalloc branch unchanged. That branch has a separate problem. That branch only creates a temporary writable fixmap alias when CONFIG_STRICT_MODULE_RWX is enabled, and otherwise assumes the target is directly writable and returns the address unchanged. That assumption no longer holds: bpf_prog_pack_alloc calls set_memory_rox() on every pack unconditionally in alloc_new_pack(), independently of any CONFIG_STRICT_*_RWX option, so BPF text in the vmalloc area is read-only regardless of what CONFIG_STRICT_MODULE_RWX says. With CONFIG_STRICT_MODULE_RWX=n, patch_map() returns the read-only address directly, the subsequent copy_to_kernel_nofault() takes a page fault and returns -EFAULT. bpf_arch_text_copy() turns that into -EINVAL, which propagates through bpf_jit_binary_pack_finalize() to the WARN_ON() in bpf_int_jit_compile() and leaves the program un-JITed. Note that BPF cannot be fixed the way kprobes was in commit bdc46e507b59 ("riscv: mm: make EXECMEM_KPROBES writable without CONFIG_STRICT_MODULE_RWX"). EXECMEM_BPF is already PAGE_KERNEL, i.e. writable at allocation time; the read-only mapping is established afterwards by generic code in alloc_new_pack(), which arch code cannot influence. The only place this can be handled is patch_map(). This is the same problem that was fixed on arm64 by commit b1480ed230ac ("arm64: patching: fix handling of execmem addresses"), and the fix is the same: CONFIG_EXECMEM is what actually tracks whether the vmalloc area can hold executable memory that needs a temporary alias to be written. CONFIG_BPF_JIT, CONFIG_KPROBES and CONFIG_MODULES all select it. Note that this is not limited to CONFIG_MODULES=n. Unlike arm64, riscv selects CONFIG_ARCH_OPTIONAL_KERNEL_RWX, so CONFIG_STRICT_MODULE_RWX can be disabled with CONFIG_MODULES=y as well, and the bug is reachable in that configuration too. The !CONFIG_MMU build is unaffected: it has its own __patch_insn_set() and __patch_insn_write() implementations and never calls patch_map(). Fixes: 2c9e5d4a0082 ("bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of") Signed-off-by: Wei-Jie Hung Reviewed-by: Pu Lehui Tested-by: Pu Lehui Link: https://patch.msgid.link/20260914115607.350097-1-imbigking12@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin --- arch/riscv/kernel/patch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index f8826f1595e16..9c9282f8a3a50 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -46,7 +46,7 @@ static __always_inline void *patch_map(void *addr, const unsigned int fixmap) if (core_kernel_text(uintaddr) || is_kernel_exittext(uintaddr)) { phys = __pa_symbol(addr); - } else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) { + } else if (IS_ENABLED(CONFIG_EXECMEM)) { struct page *page = vmalloc_to_page(addr); BUG_ON(!page); -- 2.53.0