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 B6AB8C433FE for ; Wed, 15 Dec 2021 03:58:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235705AbhLOD6H (ORCPT ); Tue, 14 Dec 2021 22:58:07 -0500 Received: from szxga03-in.huawei.com ([45.249.212.189]:29194 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235424AbhLOD6G (ORCPT ); Tue, 14 Dec 2021 22:58:06 -0500 Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4JDLxz5hxHz8vgT; Wed, 15 Dec 2021 11:55:51 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Wed, 15 Dec 2021 11:58:04 +0800 Received: from [10.174.178.55] (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Wed, 15 Dec 2021 11:58:03 +0800 Subject: Re: [PATCHv3] efi: apply memblock cap after memblock_add() To: Pingfan Liu , , CC: Rob Herring , Catalin Marinas , Will Deacon , Andrew Morton , Mike Rapoport , "Geert Uytterhoeven" , Frank Rowand , Ard Biesheuvel , Nick Terrell , References: <20211214040157.27443-3-kernelfans@gmail.com> <20211215021348.8766-1-kernelfans@gmail.com> From: "Leizhen (ThunderTown)" Message-ID: <7fa6bfd1-357d-10ad-0375-a6efdc7b89e4@huawei.com> Date: Wed, 15 Dec 2021 11:58:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20211215021348.8766-1-kernelfans@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org 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") Did you see the warning? pr_warn("%s: No memory registered yet\n", __func__); > > 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) {} >