From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 16C55288CAD for ; Wed, 9 Jul 2025 10:03:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752055429; cv=none; b=WQkcHDDNukyAWVZHQLgSSdhKFX7aLDRdzmhQ8nzSMZs4z48r0bQBPfRHOglioiCSdcTQVThyffkMPCQ5jCqcW/IAS/ZQB3/jNhdpb7EVfNdjkSxKb9aCub1/RcxVhSH7C+GCz+vNAwN958sjk0EFtH8XrY8YnhIp7qPGDeadhWw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752055429; c=relaxed/simple; bh=/i6yAE0mMp4sQnXz9cH9fSQSKgUvZ7gnkAeXCQ5cZHw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PdmSYk+tr4LsQ8NKvy536XCjuxF6XGZrg0boHDIv6+zyzvyx2s+4RnpenrDlk/kw6X5PM7NJN0TTuUlOEUcBnpklofLMUuA/hXr5L6B1IYX9Pc1LNDkLijOF8+dbQfkbpqq0jhLskuaLsHsIHaZB5Ypy1gYP6meSifEvewi1uR4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz; spf=pass smtp.mailfrom=suse.cz; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=0JD5JeLY; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=cY8jgUgk; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b=0JD5JeLY; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b=cY8jgUgk; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.cz Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="0JD5JeLY"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="cY8jgUgk"; dkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz header.b="0JD5JeLY"; dkim=permerror (0-bit key) header.d=suse.cz header.i=@suse.cz header.b="cY8jgUgk" 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 0E75021179; Wed, 9 Jul 2025 10:03:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1752055426; 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=V2LPKE++NsMhJ0AZaPll7Fd/1GSCe8P7koBFSoL8AgM=; b=0JD5JeLY2C/SjejLIFN0qpY/xt//rsYw5OysuntZ6zTWNP6thodJlFdxk6QJTuQM2Sm3tx sSiFGupjIRYhazQds5VUQ8PgK5i6iq5DsEmCJB93NBDi8hgodnqvsnNxC9bxj+6R2ez5x5 PfDvhWo2/9H0xSmaBTF8MReQenYC/Nc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1752055426; 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=V2LPKE++NsMhJ0AZaPll7Fd/1GSCe8P7koBFSoL8AgM=; b=cY8jgUgkRp68eYceVzxgp46vetfHQApVHCFxsSoRrKOn4jOtoqAn6tHhnc/reG/7elxhlb w66p2M1h314PV2AA== Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=0JD5JeLY; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=cY8jgUgk DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1752055426; 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=V2LPKE++NsMhJ0AZaPll7Fd/1GSCe8P7koBFSoL8AgM=; b=0JD5JeLY2C/SjejLIFN0qpY/xt//rsYw5OysuntZ6zTWNP6thodJlFdxk6QJTuQM2Sm3tx sSiFGupjIRYhazQds5VUQ8PgK5i6iq5DsEmCJB93NBDi8hgodnqvsnNxC9bxj+6R2ez5x5 PfDvhWo2/9H0xSmaBTF8MReQenYC/Nc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1752055426; 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=V2LPKE++NsMhJ0AZaPll7Fd/1GSCe8P7koBFSoL8AgM=; b=cY8jgUgkRp68eYceVzxgp46vetfHQApVHCFxsSoRrKOn4jOtoqAn6tHhnc/reG/7elxhlb w66p2M1h314PV2AA== 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 CAAA5136DC; Wed, 9 Jul 2025 10:03:45 +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 lleuL4E+bmhaGAAAD6G6ig (envelope-from ); Wed, 09 Jul 2025 10:03:45 +0000 Message-ID: Date: Wed, 9 Jul 2025 12:03:45 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 7/8] fs/proc/task_mmu: read proc/pid/maps under per-vma lock Content-Language: en-US To: Suren Baghdasaryan , akpm@linux-foundation.org Cc: Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, david@redhat.com, peterx@redhat.com, jannh@google.com, hannes@cmpxchg.org, mhocko@kernel.org, paulmck@kernel.org, shuah@kernel.org, adobriyan@gmail.com, brauner@kernel.org, josef@toxicpanda.com, yebin10@huawei.com, linux@weissschuh.net, willy@infradead.org, osalvador@suse.de, andrii@kernel.org, ryan.roberts@arm.com, christophe.leroy@csgroup.eu, tjmercier@google.com, kaleshsingh@google.com, aha310510@gmail.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org References: <20250704060727.724817-1-surenb@google.com> <20250704060727.724817-8-surenb@google.com> 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+fMgqZkBQJnyBr8BQka0IFQAAoJECJPp+fMgqZkqmMQ AIbGN95ptUMUvo6aAdhxaOCHXp1DfIBuIOK/zpx8ylY4pOwu3GRe4dQ8u4XS9gaZ96Gj4bC+ jwWcSmn+TjtKW3rH1dRKopvC07tSJIGGVyw7ieV/5cbFffA8NL0ILowzVg8w1ipnz1VTkWDr 2zcfslxJsJ6vhXw5/npcY0ldeC1E8f6UUoa4eyoskd70vO0wOAoGd02ZkJoox3F5ODM0kjHu Y97VLOa3GG66lh+ZEelVZEujHfKceCw9G3PMvEzyLFbXvSOigZQMdKzQ8D/OChwqig8wFBmV QCPS4yDdmZP3oeDHRjJ9jvMUKoYODiNKsl2F+xXwyRM2qoKRqFlhCn4usVd1+wmv9iLV8nPs 2Db1ZIa49fJet3Sk3PN4bV1rAPuWvtbuTBN39Q/6MgkLTYHb84HyFKw14Rqe5YorrBLbF3rl M51Dpf6Egu1yTJDHCTEwePWug4XI11FT8lK0LNnHNpbhTCYRjX73iWOnFraJNcURld1jL1nV r/LRD+/e2gNtSTPK0Qkon6HcOBZnxRoqtazTU6YQRmGlT0v+rukj/cn5sToYibWLn+RoV1CE Qj6tApOiHBkpEsCzHGu+iDQ1WT0Idtdynst738f/uCeCMkdRu4WMZjteQaqvARFwCy3P/jpK uvzMtves5HvZw33ZwOtMCgbpce00DaET4y/UzsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZ8gcVAUJFhTonwAKCRAiT6fnzIKmZLY8D/9uo3Ut9yi2YCuASWxr7QQZ lJCViArjymbxYB5NdOeC50/0gnhK4pgdHlE2MdwF6o34x7TPFGpjNFvycZqccSQPJ/gibwNA zx3q9vJT4Vw+YbiyS53iSBLXMweeVV1Jd9IjAoL+EqB0cbxoFXvnjkvP1foiiF5r73jCd4PR rD+GoX5BZ7AZmFYmuJYBm28STM2NA6LhT0X+2su16f/HtummENKcMwom0hNu3MBNPUOrujtW khQrWcJNAAsy4yMoJ2Lw51T/5X5Hc7jQ9da9fyqu+phqlVtn70qpPvgWy4HRhr25fCAEXZDp xG4RNmTm+pqorHOqhBkI7wA7P/nyPo7ZEc3L+ZkQ37u0nlOyrjbNUniPGxPxv1imVq8IyycG AN5FaFxtiELK22gvudghLJaDiRBhn8/AhXc642/Z/yIpizE2xG4KU4AXzb6C+o7LX/WmmsWP Ly6jamSg6tvrdo4/e87lUedEqCtrp2o1xpn5zongf6cQkaLZKQcBQnPmgHO5OG8+50u88D9I rywqgzTUhHFKKF6/9L/lYtrNcHU8Z6Y4Ju/MLUiNYkmtrGIMnkjKCiRqlRrZE/v5YFHbayRD dJKXobXTtCBYpLJM4ZYRpGZXne/FAtWNe4KbNJJqxMvrTOrnIatPj8NhBVI0RSJRsbilh6TE m6M14QORSWTLRg== In-Reply-To: <20250704060727.724817-8-surenb@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [-4.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCPT_COUNT_TWELVE(0.00)[28]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; MID_RHS_MATCH_FROM(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; FREEMAIL_CC(0.00)[oracle.com,redhat.com,google.com,cmpxchg.org,kernel.org,gmail.com,toxicpanda.com,huawei.com,weissschuh.net,infradead.org,suse.de,arm.com,csgroup.eu,vger.kernel.org,kvack.org]; R_RATELIMIT(0.00)[to_ip_from(RLfsxmn1qwoupcjwdqfx65548p)]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.cz:mid,suse.cz:dkim]; DNSWL_BLOCKED(0.00)[2a07:de40:b281:106:10:150:64:167:received]; DKIM_TRACE(0.00)[suse.cz:+] X-Spam-Flag: NO X-Spam-Level: X-Rspamd-Queue-Id: 0E75021179 X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Action: no action X-Spam-Score: -4.51 On 7/4/25 08:07, Suren Baghdasaryan wrote: > --- a/mm/mmap_lock.c > +++ b/mm/mmap_lock.c > @@ -178,6 +178,94 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm, > count_vm_vma_lock_event(VMA_LOCK_ABORT); > return NULL; > } > + > +static struct vm_area_struct *lock_vma_under_mmap_lock(struct mm_struct *mm, > + struct vma_iterator *iter, > + unsigned long address) > +{ > + struct vm_area_struct *vma; > + int ret; > + > + ret = mmap_read_lock_killable(mm); > + if (ret) > + return ERR_PTR(ret); > + > + /* Lookup the vma at the last position again under mmap_read_lock */ > + vma_iter_init(iter, mm, address); > + vma = vma_next(iter); > + if (vma) > + vma_start_read_locked(vma); This can in theory return false (refcount overflow?) so it should be handled? > + > + mmap_read_unlock(mm); > + > + return vma; > +} > +