From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5F65584A35; Mon, 24 Feb 2025 14:56:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740408989; cv=none; b=YFyNXfk8oPLZHIzPWfAWc8GdVbd5hqDNKrDiam67+Yp1IVkXxltS0E/BvAgGr+YU8fFNd51EMqC3plgWBihuJITzxH4vN5FRO1tXY4oSt7tXjhcs3LSjO8pC5ijpzXNjvP7LUXG9rLPlBYKWQUoCcq4U2qCfgMdkspfikXVvb+M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740408989; c=relaxed/simple; bh=o+XhRH7adXP2TjeCtKavcvpQdCB15TKR3mr6Z+Ux+CI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=trtaX0uF+KLLW13HX/g5OhpYouO/AH5YnQc86tSSojAi5wgeSSk0BHIrzIJEqdON15nCsEeliTwEYDdMx6ttbTXWG0UmQnVCcfbrAwFzItxooKux0fYw2Yv/6/db1xyuUWsJwk57xIO8GSW0zfiNS1D2h9LAUrH8JU2+DGQmNIE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sjGCjMhW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="sjGCjMhW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C63BCC4CED6; Mon, 24 Feb 2025 14:56:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1740408989; bh=o+XhRH7adXP2TjeCtKavcvpQdCB15TKR3mr6Z+Ux+CI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sjGCjMhWNjqocLsUsqbshLffjYghoo6kQ0srvEx+q0zXqxuZEH2mAwx0ksMqFFbYc MAKsxXeDNeKj+PVHDcgRqzUzIaZV6i9JBgXQ93IOXFQmvsoir+ppunYjJGSX1rSdIh 7YZdIgmXsJRsujAvW6LggWfGXNpcgsx9KS8QSHIY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Erhard Furtner , Christophe Leroy , Michael Ellerman , Madhavan Srinivasan , Sasha Levin Subject: [PATCH 6.13 022/138] powerpc/code-patching: Disable KASAN report during patching via temporary mm Date: Mon, 24 Feb 2025 15:34:12 +0100 Message-ID: <20250224142605.339496976@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250224142604.442289573@linuxfoundation.org> References: <20250224142604.442289573@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christophe Leroy [ Upstream commit dc9c5166c3cb044f8a001e397195242fd6796eee ] Erhard reports the following KASAN hit on Talos II (power9) with kernel 6.13: [ 12.028126] ================================================================== [ 12.028198] BUG: KASAN: user-memory-access in copy_to_kernel_nofault+0x8c/0x1a0 [ 12.028260] Write of size 8 at addr 0000187e458f2000 by task systemd/1 [ 12.028346] CPU: 87 UID: 0 PID: 1 Comm: systemd Tainted: G T 6.13.0-P9-dirty #3 [ 12.028408] Tainted: [T]=RANDSTRUCT [ 12.028446] Hardware name: T2P9D01 REV 1.01 POWER9 0x4e1202 opal:skiboot-bc106a0 PowerNV [ 12.028500] Call Trace: [ 12.028536] [c000000008dbf3b0] [c000000001656a48] dump_stack_lvl+0xbc/0x110 (unreliable) [ 12.028609] [c000000008dbf3f0] [c0000000006e2fc8] print_report+0x6b0/0x708 [ 12.028666] [c000000008dbf4e0] [c0000000006e2454] kasan_report+0x164/0x300 [ 12.028725] [c000000008dbf600] [c0000000006e54d4] kasan_check_range+0x314/0x370 [ 12.028784] [c000000008dbf640] [c0000000006e6310] __kasan_check_write+0x20/0x40 [ 12.028842] [c000000008dbf660] [c000000000578e8c] copy_to_kernel_nofault+0x8c/0x1a0 [ 12.028902] [c000000008dbf6a0] [c0000000000acfe4] __patch_instructions+0x194/0x210 [ 12.028965] [c000000008dbf6e0] [c0000000000ade80] patch_instructions+0x150/0x590 [ 12.029026] [c000000008dbf7c0] [c0000000001159bc] bpf_arch_text_copy+0x6c/0xe0 [ 12.029085] [c000000008dbf800] [c000000000424250] bpf_jit_binary_pack_finalize+0x40/0xc0 [ 12.029147] [c000000008dbf830] [c000000000115dec] bpf_int_jit_compile+0x3bc/0x930 [ 12.029206] [c000000008dbf990] [c000000000423720] bpf_prog_select_runtime+0x1f0/0x280 [ 12.029266] [c000000008dbfa00] [c000000000434b18] bpf_prog_load+0xbb8/0x1370 [ 12.029324] [c000000008dbfb70] [c000000000436ebc] __sys_bpf+0x5ac/0x2e00 [ 12.029379] [c000000008dbfd00] [c00000000043a228] sys_bpf+0x28/0x40 [ 12.029435] [c000000008dbfd20] [c000000000038eb4] system_call_exception+0x334/0x610 [ 12.029497] [c000000008dbfe50] [c00000000000c270] system_call_vectored_common+0xf0/0x280 [ 12.029561] --- interrupt: 3000 at 0x3fff82f5cfa8 [ 12.029608] NIP: 00003fff82f5cfa8 LR: 00003fff82f5cfa8 CTR: 0000000000000000 [ 12.029660] REGS: c000000008dbfe80 TRAP: 3000 Tainted: G T (6.13.0-P9-dirty) [ 12.029735] MSR: 900000000280f032 CR: 42004848 XER: 00000000 [ 12.029855] IRQMASK: 0 GPR00: 0000000000000169 00003fffdcf789a0 00003fff83067100 0000000000000005 GPR04: 00003fffdcf78a98 0000000000000090 0000000000000000 0000000000000008 GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR12: 0000000000000000 00003fff836ff7e0 c000000000010678 0000000000000000 GPR16: 0000000000000000 0000000000000000 00003fffdcf78f28 00003fffdcf78f90 GPR20: 0000000000000000 0000000000000000 0000000000000000 00003fffdcf78f80 GPR24: 00003fffdcf78f70 00003fffdcf78d10 00003fff835c7239 00003fffdcf78bd8 GPR28: 00003fffdcf78a98 0000000000000000 0000000000000000 000000011f547580 [ 12.030316] NIP [00003fff82f5cfa8] 0x3fff82f5cfa8 [ 12.030361] LR [00003fff82f5cfa8] 0x3fff82f5cfa8 [ 12.030405] --- interrupt: 3000 [ 12.030444] ================================================================== Commit c28c15b6d28a ("powerpc/code-patching: Use temporary mm for Radix MMU") is inspired from x86 but unlike x86 is doesn't disable KASAN reports during patching. This wasn't a problem at the begining because __patch_mem() is not instrumented. Commit 465cabc97b42 ("powerpc/code-patching: introduce patch_instructions()") use copy_to_kernel_nofault() to copy several instructions at once. But when using temporary mm the destination is not regular kernel memory but a kind of kernel-like memory located in user address space. Because it is not in kernel address space it is not covered by KASAN shadow memory. Since commit e4137f08816b ("mm, kasan, kmsan: instrument copy_from/to_kernel_nofault") KASAN reports bad accesses from copy_to_kernel_nofault(). Here a bad access to user memory is reported because KASAN detects the lack of shadow memory and the address is below TASK_SIZE. Do like x86 in commit b3fd8e83ada0 ("x86/alternatives: Use temporary mm for text poking") and disable KASAN reports during patching when using temporary mm. Reported-by: Erhard Furtner Close: https://lore.kernel.org/all/20250201151435.48400261@yea/ Fixes: 465cabc97b42 ("powerpc/code-patching: introduce patch_instructions()") Signed-off-by: Christophe Leroy Acked-by: Michael Ellerman Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/1c05b2a1b02ad75b981cfc45927e0b4a90441046.1738577687.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin --- arch/powerpc/lib/code-patching.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index af97fbb3c257e..81c0f673eb252 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -493,7 +493,9 @@ static int __do_patch_instructions_mm(u32 *addr, u32 *code, size_t len, bool rep orig_mm = start_using_temp_mm(patching_mm); + kasan_disable_current(); err = __patch_instructions(patch_addr, code, len, repeat_instr); + kasan_enable_current(); /* context synchronisation performed by __patch_instructions */ stop_using_temp_mm(patching_mm, orig_mm); -- 2.39.5