From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0A5FEC4345F for ; Tue, 30 Apr 2024 07:31:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ik/0hq6hFiEz8n5HfDnEc1HZ5swqawzE21x+9rvyQXw=; b=DVHRlgHbOmwDXo 6p738Zr5U6oTzC9QbE3NnCBvyldDoNBYW4NDtew53NYiSXj/bZ100YRfa4MCLrCqIJ75obB3vGHQ/ YnEzkTePXwN8whKmYXayFHPaDBR8TDChsezQiEsCBEp47lk/6Pw+4vx28LcpR1gXP5V2U46YfGuqh /Oe5+qUfoJLAtHsmyfSanqvyg29LwWcFpzaIQKjPYm0pQJCM4qx8FiwhxgnsRqT0o9dMQj1sHY+rY BfOmOmYeOUODppGiNp1H+MwYpKDM/tbij2OD5UW/qQfkB9tfxG5rwnvUdNC+GsBQ8Od8udfNvwn25 au5oIRLmPgb5j/mYpteg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1s1hxp-00000005Rvf-1l6L; Tue, 30 Apr 2024 07:31:45 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1s1hxQ-00000005Rlh-1dZw for linux-riscv@lists.infradead.org; Tue, 30 Apr 2024 07:31:27 +0000 Date: Tue, 30 Apr 2024 09:31:07 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1714462275; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=DqrYzQE/eh5FY4RgzTW10+8t5SwsCC9zr0+QvqJHjrc=; b=gZj4YxjG906AKACZuGLWmHr5AMq85uWqbLLVO7IobnuUbSLwcu+Ja6ppeFHLMasAnVIg7D RV/Hyn3blm+ooOu7eTVMrwnNq8Kejn5d9fceqS6uhC2RMTfZCFjX67nm4vTY47TLf4OOvY VmWXIk6Bbp7pKw3TH9Ind5RYBx2YLK69fYTXZqhVNdoW60WJjCx54pno+VtfWUa0GE8a44 Dh4dmkmzbwdXh96opJ9qVU0xra/rYoqmwmXgM3dg2PQDUxd4aDCaOAgT5d8C7TUYp/371r X8zLAQAehJX7TQC3+0Bj9IetHM5Fy9hH6NIIS07dsNCpSlr8CLE2kTwkAJe45g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1714462275; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=DqrYzQE/eh5FY4RgzTW10+8t5SwsCC9zr0+QvqJHjrc=; b=8AdA6xDHGkSuRiD6v8behqV1g2AbTjtevYIkGQ44lTzvNa3hHHgrj18SkOJt4ZoW9u8BJR tAsH9vf3SHlsL8CQ== From: Nam Cao To: Joel Granados Cc: Mike Rapoport , Andreas Dilger , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , linux-riscv@lists.infradead.org, Thomas Gleixner , Andrew Morton , "ndesaulniers @ google . com" , Luis Chamberlain , Ingo Molnar , Christophe Leroy , Tejun Heo , Krister Johansen , Changbin Du , Arnd Bergmann , Geert Uytterhoeven , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] init: fix allocated page overlapping with PTR_ERR Message-ID: <20240430073056.bEG4-yk8@linutronix.de> References: <20240418102943.180510-1-namcao@linutronix.de> <20240429125230.s5pbeye24iw5aurz@joelS2.panther.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240429125230.s5pbeye24iw5aurz@joelS2.panther.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240430_003120_824536_0B899F89 X-CRM114-Status: GOOD ( 37.63 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Mon, Apr 29, 2024 at 02:52:30PM +0200, Joel Granados wrote: > On Thu, Apr 18, 2024 at 12:29:43PM +0200, Nam Cao wrote: > > There is nothing preventing kernel memory allocators from allocating a > > page that overlaps with PTR_ERR(), except for architecture-specific > > code that setup memblock. > > > > It was discovered that RISCV architecture doesn't setup memblock > > corectly, leading to a page overlapping with PTR_ERR() being allocated, > > and subsequently crashing the kernel (link in Close: ) > > > > The reported crash has nothing to do with PTR_ERR(): the last page > > (at address 0xfffff000) being allocated leads to an unexpected > > arithmetic overflow in ext4; but still, this page shouldn't be > > allocated in the first place. > > > > Because PTR_ERR() is an architecture-independent thing, we shouldn't > > ask every single architecture to set this up. There may be other > > architectures beside RISCV that have the same problem. > > > > Fix this one and for all by reserving the physical memory page that > > may be mapped to the last virtual memory page as part of low memory. > > > > Unfortunately, this means if there is actual memory at this reserved > > location, that memory will become inaccessible. However, if this page > > is not reserved, it can only be accessed as high memory, so this > > doesn't matter if high memory is not supported. Even if high memory is > > supported, it is still only one page. > > > > Closes: https://lore.kernel.org/linux-riscv/878r1ibpdn.fsf@all.your.base.are.belong.to.us > > Signed-off-by: Nam Cao > > Cc: # all versions > > --- > > init/main.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/init/main.c b/init/main.c > > index 881f6230ee59..f8d2793c4641 100644 > > --- a/init/main.c > > +++ b/init/main.c > > @@ -900,6 +900,7 @@ void start_kernel(void) > > page_address_init(); > > pr_notice("%s", linux_banner); > > early_security_init(); > > + memblock_reserve(__pa(-PAGE_SIZE), PAGE_SIZE); /* reserve last page for ERR_PTR */ > > setup_arch(&command_line); > > setup_boot_config(); > > setup_command_line(command_line); > > -- > > 2.39.2 > > > > I received a similar(ish) report recently > https://lore.kernel.org/oe-kbuild-all/202404211031.J6l2AfJk-lkp@intel.com/ > regarding RISC-V in init/mail.c. Here is the meat of the report in case > you want to avoid going to the actual link: This issue doesn't look like it has anything to do with this patch: this patch is about overlapping of dynamically allocated memory, while I think the issue is about overlapping sections during linking (maybe something wrong with riscv linker script?) Also, FWIW, this patch is not going to be in mainline because of a regression. Nonetheless, I will have a look at this later. Best regards, Nam > " > ... > riscv64-linux-ld: section .data LMA [000000000099b000,0000000001424de7] overlaps section .text LMA [0000000000104040,000000000213c543] > riscv64-linux-ld: section .data..percpu LMA [00000000024e2000,00000000026b46e7] overlaps section .rodata LMA [000000000213c580,000000000292d0dd] > riscv64-linux-ld: section .rodata VMA [ffffffff8213c580,ffffffff8292d0dd] overlaps section .data VMA [ffffffff82000000,ffffffff82a89de7] > init/main.o: in function `rdinit_setup': > >> init/main.c:613:(.init.text+0x358): relocation truncated to fit: R_RISCV_GPREL_I against symbol `__setup_start' defined in .init.rodata section in .tmp_vmlinux.kallsyms1 > net/ipv4/ipconfig.o: in function `ic_dhcp_init_options': > net/ipv4/ipconfig.c:682:(.init.text+0x9b4): relocation truncated to fit: R_RISCV_GPREL_I against `ic_bootp_cookie' > net/sunrpc/auth_gss/gss_krb5_mech.o: in function `gss_krb5_prepare_enctype_priority_list': > >> net/sunrpc/auth_gss/gss_krb5_mech.c:213:(.text.gss_krb5_prepare_enctype_priority_list+0x9c): relocation truncated to fit: R_RISCV_GPREL_I against `gss_krb5_enctypes.0' > lib/maple_tree.o: in function `mas_leaf_max_gap': > >> lib/maple_tree.c:1512:(.text.mas_leaf_max_gap+0x2b8): relocation truncated to fit: R_RISCV_GPREL_I against `mt_pivots' > lib/maple_tree.o: in function `ma_dead_node': > >> lib/maple_tree.c:560:(.text.mas_data_end+0x110): relocation truncated to fit: R_RISCV_GPREL_I against `mt_pivots' > lib/maple_tree.o: in function `mas_extend_spanning_null': > >> lib/maple_tree.c:3662:(.text.mas_extend_spanning_null+0x69c): relocation truncated to fit: R_RISCV_GPREL_I against `mt_pivots' > lib/maple_tree.o: in function `mas_mab_cp': > >> lib/maple_tree.c:1943:(.text.mas_mab_cp+0x248): relocation truncated to fit: R_RISCV_GPREL_I against `mt_pivots' > lib/maple_tree.o: in function `mab_mas_cp': > >> lib/maple_tree.c:2000:(.text.mab_mas_cp+0x15c): relocation truncated to fit: R_RISCV_GPREL_I against `mt_pivots' > lib/maple_tree.o: in function `mas_reuse_node': > >> lib/maple_tree.c:3416:(.text.mas_reuse_node+0x17c): relocation truncated to fit: R_RISCV_GPREL_I against `mt_slots' > lib/maple_tree.o: in function `mt_free_walk': > >> lib/maple_tree.c:5238:(.text.mt_free_walk+0x15c): relocation truncated to fit: R_RISCV_GPREL_I against `mt_slots' > lib/maple_tree.o: in function `mtree_lookup_walk': > lib/maple_tree.c:3700:(.text.mtree_lookup_walk+0x94): additional relocation overflows omitted from the output > ... > > " > > Could the fix that you have posted here be related to that report? > Comments are greatly appreciated. > > Best > -- > > Joel Granados _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv