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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABB12C433F5 for ; Wed, 15 Dec 2021 05:29:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239873AbhLOF3x (ORCPT ); Wed, 15 Dec 2021 00:29:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231590AbhLOF3x (ORCPT ); Wed, 15 Dec 2021 00:29:53 -0500 Received: from mail-pl1-x62d.google.com (mail-pl1-x62d.google.com [IPv6:2607:f8b0:4864:20::62d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B87ACC061574; Tue, 14 Dec 2021 21:29:52 -0800 (PST) Received: by mail-pl1-x62d.google.com with SMTP id w24so2760929ply.12; Tue, 14 Dec 2021 21:29:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=mSRd1l3jXtE+KZB/nZIfmfmh0C/1YzDMwQkHsDhD0zE=; b=XNi0rBVcE6PxLrvtPrEccoLm6jp9M2wD9lwnaqgUfKaItl4qV+Aq1LyuHl4i+BPFs6 2i4R/QoOWZ+d+fCN9JKiRDVvTHmwfzqPncuWsVwiuJIyndoLefBkd3IXGD56PuMFo0Kn MS07ZTfMFogLTF5zemcz/NdW4McgSWtB6ljydXHe2fh9kc19DsaRlAa63FLXBj625xnK QKdmJ5cSd/3s4VtHEjapUXAAyBo+qJJKldz+NskEyWmxWNfu6Z6z/yI/2apYCWC42pif GS16d92iGsedbIaocV/wBs1s3Rapjgu6NU5nJX5ZDvfhX34C1tanlamIkOhXcyni07/y 3OlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=mSRd1l3jXtE+KZB/nZIfmfmh0C/1YzDMwQkHsDhD0zE=; b=larxYZqNfARRHiQRrvlLSGCNktiSl3mN8mwB6bZAzGga7BUT//S7tbzIkcmBccIbge G7pu91DSX9Z4/XvQbyH9xxHqjgI43bPcQSnJlGJfcZIdZ7o2gtGNST+0hJ0ksFfI69eH LSz1GxF/2FaFKoglu+9RtwHGTbq5R/erm2FLa5eiC2gvGtcCY15JT5DWVhn8LFaU7TAB gjYfK3vYqTVVGj5vxt6AWGwD2I6rEMkyfWNt5yCJKKG4Ec32tAj7Rr8+HjDdmNJrPaP5 6ERXrz2niWY8XXbaw2sV3Pe57D6aSGtCKBpOp9PXsnAm2TtxxW4EuEGgo69qHABmNqzD 1yFg== X-Gm-Message-State: AOAM530fSbkGRKL2YChTShAHWweZaSRge6Y/KeWnUw17jAQfCuQxxsCq g99/5H7l/MZfbf8OB4KFS1ud7ntbnA== X-Google-Smtp-Source: ABdhPJzqTFLP7+bCuIXeE/eOIKrOhS1QoRWB1PmgRXJdGanNHPdx2NUizoCTmloZXKTW+ppDun1MfQ== X-Received: by 2002:a17:902:9343:b0:148:a2e7:fb5f with SMTP id g3-20020a170902934300b00148a2e7fb5fmr3012697plp.160.1639546192244; Tue, 14 Dec 2021 21:29:52 -0800 (PST) Received: from piliu.users.ipa.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id s8sm871424pfw.75.2021.12.14.21.29.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Dec 2021 21:29:51 -0800 (PST) Date: Wed, 15 Dec 2021 13:29:41 +0800 From: Pingfan Liu To: "Leizhen (ThunderTown)" Cc: devicetree@vger.kernel.org, linux-efi@vger.kernel.org, Rob Herring , Catalin Marinas , Will Deacon , Andrew Morton , Mike Rapoport , Geert Uytterhoeven , Frank Rowand , Ard Biesheuvel , Nick Terrell , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCHv3] efi: apply memblock cap after memblock_add() Message-ID: References: <20211214040157.27443-3-kernelfans@gmail.com> <20211215021348.8766-1-kernelfans@gmail.com> <7fa6bfd1-357d-10ad-0375-a6efdc7b89e4@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7fa6bfd1-357d-10ad-0375-a6efdc7b89e4@huawei.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, Dec 15, 2021 at 11:58:03AM +0800, Leizhen (ThunderTown) wrote: > > > On 2021/12/15 10:13, Pingfan Liu wrote: > > On arm64, during kdump kernel saves vmcore, it runs into the following bug: > > ... > > [ 15.148919] usercopy: Kernel memory exposure attempt detected from SLUB object 'kmem_cache_node' (offset 0, size 4096)! > > [ 15.159707] ------------[ cut here ]------------ > > [ 15.164311] kernel BUG at mm/usercopy.c:99! > > [ 15.168482] Internal error: Oops - BUG: 0 [#1] SMP > > [ 15.173261] Modules linked in: xfs libcrc32c crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce sbsa_gwdt ast i2c_algo_bit drm_vram_helper drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops cec drm_ttm_helper ttm drm nvme nvme_core xgene_hwmon i2c_designware_platform i2c_designware_core dm_mirror dm_region_hash dm_log dm_mod overlay squashfs zstd_decompress loop > > [ 15.206186] CPU: 0 PID: 542 Comm: cp Not tainted 5.16.0-rc4 #1 > > [ 15.212006] Hardware name: GIGABYTE R272-P30-JG/MP32-AR0-JG, BIOS F12 (SCP: 1.5.20210426) 05/13/2021 > > [ 15.221125] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > > [ 15.228073] pc : usercopy_abort+0x9c/0xa0 > > [ 15.232074] lr : usercopy_abort+0x9c/0xa0 > > [ 15.236070] sp : ffff8000121abba0 > > [ 15.239371] x29: ffff8000121abbb0 x28: 0000000000003000 x27: 0000000000000000 > > [ 15.246494] x26: 0000000080000400 x25: 0000ffff885c7000 x24: 0000000000000000 > > [ 15.253617] x23: 000007ff80400000 x22: ffff07ff80401000 x21: 0000000000000001 > > [ 15.260739] x20: 0000000000001000 x19: ffff07ff80400000 x18: ffffffffffffffff > > [ 15.267861] x17: 656a626f2042554c x16: 53206d6f72662064 x15: 6574636574656420 > > [ 15.274983] x14: 74706d6574746120 x13: 2129363930342065 x12: 7a6973202c302074 > > [ 15.282105] x11: ffffc8b041d1b148 x10: 00000000ffff8000 x9 : ffffc8b04012812c > > [ 15.289228] x8 : 00000000ffff7fff x7 : ffffc8b041d1b148 x6 : 0000000000000000 > > [ 15.296349] x5 : 0000000000000000 x4 : 0000000000007fff x3 : 0000000000000000 > > [ 15.303471] x2 : 0000000000000000 x1 : ffff07ff8c064800 x0 : 000000000000006b > > [ 15.310593] Call trace: > > [ 15.313027] usercopy_abort+0x9c/0xa0 > > [ 15.316677] __check_heap_object+0xd4/0xf0 > > [ 15.320762] __check_object_size.part.0+0x160/0x1e0 > > [ 15.325628] __check_object_size+0x2c/0x40 > > [ 15.329711] copy_oldmem_page+0x7c/0x140 > > [ 15.333623] read_from_oldmem.part.0+0xfc/0x1c0 > > [ 15.338142] __read_vmcore.constprop.0+0x23c/0x350 > > [ 15.342920] read_vmcore+0x28/0x34 > > [ 15.346309] proc_reg_read+0xb4/0xf0 > > [ 15.349871] vfs_read+0xb8/0x1f0 > > [ 15.353088] ksys_read+0x74/0x100 > > [ 15.356390] __arm64_sys_read+0x28/0x34 > > ... > > > > This bug introduced by commit b261dba2fdb2 ("arm64: kdump: Remove custom > > linux,usable-memory-range handling"), which moves > > memblock_cap_memory_range() to fdt, but it breaches the rules that > > memblock_cap_memory_range() should come after memblock_add() etc as said > > in commit e888fa7bb882 ("memblock: Check memory add/cap ordering"). > > void __init early_init_dt_scan_nodes(void) > { > //(1) -->early_init_dt_check_for_usable_mem_range, fill cap_mem_addr > rc = of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line); > > //(2) --> early_init_dt_add_memory_arch --> memblock_add() > of_scan_flat_dt(early_init_dt_scan_memory, NULL); > > //(3) > memblock_cap_memory_range(cap_mem_addr, cap_mem_size); > } > > I didn't get it. The above step (1),(2),(3) comply with > commit e888fa7bb882 ("memblock: Check memory add/cap ordering") > Well, at this scope, it does. But from a larger scope, let's say on arm64, setup_arch ... setup_machine_fdt(); //which holds your case ... efi_init(); //which call memblock_add, and breach the ordering. > Did you see the warning? > pr_warn("%s: No memory registered yet\n", __func__); > Yes, I did see this message, which brings me to commit e888fa7bb882 ("memblock: Check memory add/cap ordering") I am also curious why this bug does not be discovered. Is CONFIG_EFI on at your case? Thanks, Pingfan > > > > As a consequence, the virtual address set up by copy_oldmem_page() does > > not bail out from the test of virt_addr_valid() in check_heap_object(), > > and finally hits the BUG_ON(). > > > > Since memblock allocator has no idea about when the memblock is fully > > populated, while efi_init() is aware, so tackling this issue by calling the > > interface early_init_dt_check_for_usable_mem_range() exposed by of/fdt. > > > > Fixes: b261dba2fdb2 ("arm64: kdump: Remove custom linux,usable-memory-range handling") > > Signed-off-by: Pingfan Liu > > Cc: Rob Herring > > Cc: Zhen Lei > > Cc: Catalin Marinas > > Cc: Will Deacon > > Cc: Andrew Morton > > Cc: Mike Rapoport > > Cc: Geert Uytterhoeven > > Cc: Frank Rowand > > Cc: Ard Biesheuvel > > Cc: Nick Terrell > > Cc: linux-arm-kernel@lists.infradead.org > > To: devicetree@vger.kernel.org > > To: linux-efi@vger.kernel.org > > --- > > v2 -> v3: > > use static inline stub to avoid #ifdef according to Rob's suggestion > > > > drivers/firmware/efi/efi-init.c | 5 +++++ > > drivers/of/fdt.c | 2 +- > > include/linux/of_fdt.h | 2 ++ > > 3 files changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/firmware/efi/efi-init.c b/drivers/firmware/efi/efi-init.c > > index b19ce1a83f91..b2c829e95bd1 100644 > > --- a/drivers/firmware/efi/efi-init.c > > +++ b/drivers/firmware/efi/efi-init.c > > @@ -235,6 +235,11 @@ void __init efi_init(void) > > } > > > > reserve_regions(); > > + /* > > + * For memblock manipulation, the cap should come after the memblock_add(). > > + * And now, memblock is fully populated, it is time to do capping. > > + */ > > + early_init_dt_check_for_usable_mem_range(); > > efi_esrt_init(); > > efi_mokvar_table_init(); > > > > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c > > index 18a2df431bfd..aa07ef5cab5f 100644 > > --- a/drivers/of/fdt.c > > +++ b/drivers/of/fdt.c > > @@ -972,7 +972,7 @@ static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND; > > * location from flat tree > > * @node: reference to node containing usable memory range location ('chosen') > > */ > > -static void __init early_init_dt_check_for_usable_mem_range(void) > > +void __init early_init_dt_check_for_usable_mem_range(void) > > { > > const __be32 *prop; > > int len; > > diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h > > index cf48983d3c86..ad09beb6d13c 100644 > > --- a/include/linux/of_fdt.h > > +++ b/include/linux/of_fdt.h > > @@ -62,6 +62,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname, > > int depth, void *data); > > extern int early_init_dt_scan_memory(unsigned long node, const char *uname, > > int depth, void *data); > > +extern void early_init_dt_check_for_usable_mem_range(void); > > extern int early_init_dt_scan_chosen_stdout(void); > > extern void early_init_fdt_scan_reserved_mem(void); > > extern void early_init_fdt_reserve_self(void); > > @@ -86,6 +87,7 @@ extern void unflatten_and_copy_device_tree(void); > > extern void early_init_devtree(void *); > > extern void early_get_first_memblock_info(void *, phys_addr_t *); > > #else /* CONFIG_OF_EARLY_FLATTREE */ > > +static inline void early_init_dt_check_for_usable_mem_range(void) {} > > static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; } > > static inline void early_init_fdt_scan_reserved_mem(void) {} > > static inline void early_init_fdt_reserve_self(void) {} > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel