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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B4CBD60D17 for ; Wed, 20 Nov 2024 09:37:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1C8666B0083; Wed, 20 Nov 2024 04:37:46 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 178766B0085; Wed, 20 Nov 2024 04:37:46 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F347F6B0088; Wed, 20 Nov 2024 04:37:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id CE0EA6B0083 for ; Wed, 20 Nov 2024 04:37:45 -0500 (EST) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 7E9031409A9 for ; Wed, 20 Nov 2024 09:37:45 +0000 (UTC) X-FDA: 82805970366.11.5C8E6C9 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) by imf19.hostedemail.com (Postfix) with ESMTP id 91D241A0012 for ; Wed, 20 Nov 2024 09:36:38 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=c5ka4WPJ; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=Hd9J21v3; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=xdhMsyxC; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=e+nSHZSM; dmarc=none; spf=pass (imf19.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.130 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1732095278; a=rsa-sha256; cv=none; b=AqgheCH493pPXFk3XYENFQb/nnGXVQL1I9A5Do6a9GH7ZbL3E/z5SY7z8zj6N/iYALNcXs FYot21BD0QOVNoaEN1xDtVve3kNgxkiIqfHS0xNvQ6hHjTQvNsITSHMTTiYMmm3ouIWdbd iIdjVGBvTkEI29YjfVxr1fRZMy7UEm4= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=c5ka4WPJ; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=Hd9J21v3; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=xdhMsyxC; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=e+nSHZSM; dmarc=none; spf=pass (imf19.hostedemail.com: domain of vbabka@suse.cz designates 195.135.223.130 as permitted sender) smtp.mailfrom=vbabka@suse.cz ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1732095278; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=SkiTqCEmV1Qwt5HMXO6+RKgh/MgDqVWS8XUrBALrZVs=; b=nCf4CGlwv35qVzkQC1J3uvyXOFo7qJwgZkTchogphwZarMEzbXpMEtpE7qoWR53MShfVM1 G08z+KWDiaozWZYlSxdHk5rEJeS9TnJZvSlfeH0shzYYB7Pla8NTAPeA3gmzd0O5kBHmeV QVnjFaMEQ2+G6MtKoHGsszuli/MtGSs= Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id D9607219E5; Wed, 20 Nov 2024 09:37:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1732095461; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=SkiTqCEmV1Qwt5HMXO6+RKgh/MgDqVWS8XUrBALrZVs=; b=c5ka4WPJ6oDKocZ1lrZA3NKKJIHI5cRYzMbKx3slrnAmGDP3movWIjwCR+qEAvT9KMSQe7 nqoYnjWf93jOR7SLq3Nc33RAvkxEJb62QLF307/wRVsL8NsgHNTlzmhrDs5Y7RuMHuN7zO 4lBXgxVExiWmz5xX+OibFuNxi5KT5BE= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1732095461; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=SkiTqCEmV1Qwt5HMXO6+RKgh/MgDqVWS8XUrBALrZVs=; b=Hd9J21v3EVHmtUiIfG5v2s8tF7W+Hc4ePi2tywDh1Aeyxq8VdYxpU+hANS7tOL50zIOmI0 EYFxxpR/csreXdCg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1732095460; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=SkiTqCEmV1Qwt5HMXO6+RKgh/MgDqVWS8XUrBALrZVs=; b=xdhMsyxCiye7E7LUVmiDp5RS+4ZN0576bI+W4NsDYH3xCkZGUaB1NP4kkENJv7J4LEN4XG /uSO7+9p/RNOPk3YqtjZOBR12tJDBJNCCWOkX2nEmZauQHKK127NzqU0msMRsplupil4FV vZWCYWXXIEsA1r9CXfLtqS0jN0acDxw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1732095460; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=SkiTqCEmV1Qwt5HMXO6+RKgh/MgDqVWS8XUrBALrZVs=; b=e+nSHZSMtdhaxYZdkDCBR+cr0qgrDLBDjG39DI8fd5qrMODaSW+ADuu6Rb33b0PK9BDDyo CBC21HjvRHaKzyBg== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id BC82013297; Wed, 20 Nov 2024 09:37:40 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 98lFLeStPWerVAAAD6G6ig (envelope-from ); Wed, 20 Nov 2024 09:37:40 +0000 Message-ID: Date: Wed, 20 Nov 2024 10:37:40 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 03/14] io_uring: specify freeptr usage for SLAB_TYPESAFE_BY_RCU io_kiocb cache Content-Language: en-US To: Geert Uytterhoeven , Kees Cook Cc: Jens Axboe , Jann Horn , Guenter Roeck , io-uring@vger.kernel.org, linux-m68k , Christian Brauner , Linux MM , Linux Kernel Mailing List References: <20241029152249.667290-1-axboe@kernel.dk> <5a7528c4-4391-4bd9-bbdb-a0247f3c76a9@kernel.dk> <5851cd28-b369-4c09-876c-62c4a47c5982@kernel.dk> <358710e8-a826-46df-9846-5a9e0f7c6851@kernel.dk> <82b97543-ad01-4e42-b79c-12d97c1df194@kernel.dk> <4623f30c-a12e-4ba6-ad99-835764611c67@kernel.dk> <47a16a83-52c7-4779-9ed3-f16ea547b9f0@roeck-us.net> <6c3d73a5-b5ef-455f-92db-e6b96ef22fba@kernel.dk> <8b95a694-ecd4-4b6d-8032-049894dec2c1@suse.cz> From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSBWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBzdXNlLmN6PsLBlAQTAQoAPgIbAwULCQgHAwUVCgkICwUWAgMBAAIe AQIXgBYhBKlA1DSZLC6OmRA9UCJPp+fMgqZkBQJkBREIBQkRadznAAoJECJPp+fMgqZkNxIQ ALZRqwdUGzqL2aeSavbum/VF/+td+nZfuH0xeWiO2w8mG0+nPd5j9ujYeHcUP1edE7uQrjOC Gs9sm8+W1xYnbClMJTsXiAV88D2btFUdU1mCXURAL9wWZ8Jsmz5ZH2V6AUszvNezsS/VIT87 AmTtj31TLDGwdxaZTSYLwAOOOtyqafOEq+gJB30RxTRE3h3G1zpO7OM9K6ysLdAlwAGYWgJJ V4JqGsQ/lyEtxxFpUCjb5Pztp7cQxhlkil0oBYHkudiG8j1U3DG8iC6rnB4yJaLphKx57NuQ PIY0Bccg+r9gIQ4XeSK2PQhdXdy3UWBr913ZQ9AI2usid3s5vabo4iBvpJNFLgUmxFnr73SJ KsRh/2OBsg1XXF/wRQGBO9vRuJUAbnaIVcmGOUogdBVS9Sun/Sy4GNA++KtFZK95U7J417/J Hub2xV6Ehc7UGW6fIvIQmzJ3zaTEfuriU1P8ayfddrAgZb25JnOW7L1zdYL8rXiezOyYZ8Fm ZyXjzWdO0RpxcUEp6GsJr11Bc4F3aae9OZtwtLL/jxc7y6pUugB00PodgnQ6CMcfR/HjXlae h2VS3zl9+tQWHu6s1R58t5BuMS2FNA58wU/IazImc/ZQA+slDBfhRDGYlExjg19UXWe/gMcl De3P1kxYPgZdGE2eZpRLIbt+rYnqQKy8UxlszsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZAUSmwUJDK5EZgAKCRAiT6fnzIKmZOJGEACOKABgo9wJXsbWhGWYO7mD 8R8mUyJHqbvaz+yTLnvRwfe/VwafFfDMx5GYVYzMY9TWpA8psFTKTUIIQmx2scYsRBUwm5VI EurRWKqENcDRjyo+ol59j0FViYysjQQeobXBDDE31t5SBg++veI6tXfpco/UiKEsDswL1WAr tEAZaruo7254TyH+gydURl2wJuzo/aZ7Y7PpqaODbYv727Dvm5eX64HCyyAH0s6sOCyGF5/p eIhrOn24oBf67KtdAN3H9JoFNUVTYJc1VJU3R1JtVdgwEdr+NEciEfYl0O19VpLE/PZxP4wX PWnhf5WjdoNI1Xec+RcJ5p/pSel0jnvBX8L2cmniYnmI883NhtGZsEWj++wyKiS4NranDFlA HdDM3b4lUth1pTtABKQ1YuTvehj7EfoWD3bv9kuGZGPrAeFNiHPdOT7DaXKeHpW9homgtBxj 8aX/UkSvEGJKUEbFL9cVa5tzyialGkSiZJNkWgeHe+jEcfRT6pJZOJidSCdzvJpbdJmm+eED w9XOLH1IIWh7RURU7G1iOfEfmImFeC3cbbS73LQEFGe1urxvIH5K/7vX+FkNcr9ujwWuPE9b 1C2o4i/yZPLXIVy387EjA6GZMqvQUFuSTs/GeBcv0NjIQi8867H3uLjz+mQy63fAitsDwLmR EP+ylKVEKb0Q2A== In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Stat-Signature: 5158igmodjpaea8hhmftm6fm7scgz5k9 X-Rspamd-Queue-Id: 91D241A0012 X-Rspamd-Server: rspam08 X-Rspam-User: X-HE-Tag: 1732095398-133452 X-HE-Meta: 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 ltYnVACn +2dplWAyiM1yen20jPQ/atbh0p36Ia94Iccu2Azl8U/tsWYOwmRlXR3YpIKNDpBxUJv50F7nt+iauoUjSbzzy+M0OqLkKdY/9jdNixHnXbY+LuzlGSaHApBCQ59CQZFmaK0UQNmFo7iMa6zcgcQWsUcqxAYpMiq6MZhzcrKOBkZjpmvM9itOZQQToGLoqyBTWu1kzqzZMAt8lrkWL55wulD6yZucWtZJY/g6LJvkV2J51ujcJpsM7LFwPu8cZHrWOGikHuKXq7o7eEZEpwgVWo92qTI7O6NZzHH/R2hNSm+hWe8IkMLDvcUoH6VVDG2DCr8lX+hrxhZz1cvI+Hzm8pNbIcELfHkSKT2JEvjJHRxXPLHtCGskkczkE0uWAw8tuvLuez2geleazC+U= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 11/20/24 10:07, Geert Uytterhoeven wrote: > Hi Vlastimil, > >> >> >> >> diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h >> >> index 593c10a02144..8ed9c6923668 100644 >> >> --- a/include/linux/io_uring_types.h >> >> +++ b/include/linux/io_uring_types.h >> >> @@ -674,7 +674,11 @@ struct io_kiocb { >> >> struct io_kiocb *link; >> >> /* custom credentials, valid IFF REQ_F_CREDS is set */ >> >> const struct cred *creds; >> >> - struct io_wq_work work; >> >> + >> >> + union { >> >> + struct io_wq_work work; >> >> + freeptr_t freeptr __aligned(sizeof(freeptr_t)); >> > >> > I'd rather add the __aligned() to the definition of freeptr_t, so it >> > applies to all (future) users. >> > >> > But my main question stays: why is the slab code checking >> > IS_ALIGNED(args->freeptr_offset, sizeof(freeptr_t)? >> >> I believe it's to match how SLUB normally calculates the offset if no >> explicit one is given, in calculate_sizes(): >> >> s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *)); >> >> Yes there's a sizeof(void *) because freepointer used to be just that and we >> forgot to update this place when freepointer_t was introduced (by Jann in >> 44f6a42d49350) for handling CONFIG_SLAB_FREELIST_HARDENED. In >> get_freepointer() you can see how there's a cast to a pointer eventually. >> >> Does m68k have different alignment for pointer and unsigned long or both are >> 2 bytes? Or any other arch, i.e. should get_freepointer be a union with >> unsigned long and void * instead? (or it doesn't matter?) > > The default alignment for int, long, and pointer is 2 on m68k. > On CRIS (no longer supported by Linux), it was 1, IIRC. > So the union won't make a difference. > >> > Perhaps that was just intended to be __alignof__ instead of sizeof()? >> >> Would it do the right thing everywhere, given the explanation above? > > It depends. Does anything rely on the offset being a multiple of (at > least) 4? > E.g. does anything counts in multiples of longs (hi BCPL! ;-), or are > the 2 LSB used for a special purpose? (cfr. maple_tree, which uses > bit 0 (https://elixir.bootlin.com/linux/v6.12/source/include/linux/maple_tree.h#L46)? AFAIK no, the goal was just to prevent misaligned accesses. Kees added the: s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *)); so maybe he had something else in mind. But I suspect it was just because the code already used it elsewhere. So we might want something like this? But that would be safer for 6.14 so I'd suggest the io_uring specific fix meanwhile. Or maybe just add the union with freeptr_t but without __aligned plus the part below that changes mm/slab_common.c only, as the 6.13 io_uring fix? diff --git a/mm/slab_common.c b/mm/slab_common.c index 893d32059915..477fa471da18 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -230,7 +230,7 @@ static struct kmem_cache *create_cache(const char *name, if (args->use_freeptr_offset && (args->freeptr_offset >= object_size || !(flags & SLAB_TYPESAFE_BY_RCU) || - !IS_ALIGNED(args->freeptr_offset, sizeof(freeptr_t)))) + !IS_ALIGNED(args->freeptr_offset, __alignof__(freeptr_t)))) goto out; err = -ENOMEM; diff --git a/mm/slub.c b/mm/slub.c index 5b832512044e..6ad904be7700 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5287,11 +5287,7 @@ static int calculate_sizes(struct kmem_cache_args *args, struct kmem_cache *s) unsigned int size = s->object_size; unsigned int order; - /* - * Round up object size to the next word boundary. We can only - * place the free pointer at word boundaries and this determines - * the possible location of the free pointer. - */ + /* Round up object size to the next word boundary. */ size = ALIGN(size, sizeof(void *)); #ifdef CONFIG_SLUB_DEBUG @@ -5325,7 +5321,7 @@ static int calculate_sizes(struct kmem_cache_args *args, struct kmem_cache *s) if (((flags & SLAB_TYPESAFE_BY_RCU) && !args->use_freeptr_offset) || (flags & SLAB_POISON) || s->ctor || ((flags & SLAB_RED_ZONE) && - (s->object_size < sizeof(void *) || slub_debug_orig_size(s)))) { + (s->object_size < sizeof(freeptr_t) || slub_debug_orig_size(s)))) { /* * Relocate free pointer after the object if it is not * permitted to overwrite the first word of the object on @@ -5343,7 +5339,7 @@ static int calculate_sizes(struct kmem_cache_args *args, struct kmem_cache *s) * longer true, the function needs to be modified. */ s->offset = size; - size += sizeof(void *); + size += sizeof(freeptr_t); } else if ((flags & SLAB_TYPESAFE_BY_RCU) && args->use_freeptr_offset) { s->offset = args->freeptr_offset; } else { @@ -5352,7 +5348,7 @@ static int calculate_sizes(struct kmem_cache_args *args, struct kmem_cache *s) * it away from the edges of the object to avoid small * sized over/underflows from neighboring allocations. */ - s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *)); + s->offset = ALIGN_DOWN(s->object_size / 2, __alignof__(freeptr_t)); } #ifdef CONFIG_SLUB_DEBUG