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Wed, 23 Oct 2024 08:37:04 +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 40OtKrC1GGfLGwAAD6G6ig (envelope-from ); Wed, 23 Oct 2024 08:37:04 +0000 Message-ID: <2ae61141-9d88-4493-9fc1-245e29dac445@suse.cz> Date: Wed, 23 Oct 2024 10:37:04 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH hotfix 6.12 0/8] fix error handling in mmap_region() and refactor Content-Language: en-US To: Lorenzo Stoakes , Andrew Morton Cc: "Liam R . Howlett" , Jann Horn , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Peter Xu References: 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-Rspam-User: X-Rspamd-Queue-Id: D5B5040015 X-Rspamd-Server: rspam01 X-Stat-Signature: bp7k3t4t8c3y7uokmxkf6nzs4oigkyno X-HE-Tag: 1729672619-341529 X-HE-Meta: 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 jYR3Tegu zxlVr2tEGOw96YGItZnkaKNRpDS2ySduMpurv2rkNMJsz6LqAkLez41MofLaiL+eTph0aI9wmhg/tulWdu9mxh2S0ikH3tYFki7ekogQyLSk06ik6tJGZYUPXphyNFCylz8U8VlD3g5xwpVcaxZGHdbbKyEV37KQB+LRZODDuSCeKfRqHX+4S6Bj7Z61sQ0D8eMS61nT9E0v3WrLEElAmoFI30YZwcgFxnl/X8JNsiv/vSf28HGnL5MOjs6MfohFLsF8a3Ex5Q+yXXkZk1LPVcRUjd/l9CIYHtzSXU5dXxP3GYOlmhwPevGpg2E2PZSUfdxVbSHj7MRQGTn0= 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 10/22/24 22:40, Lorenzo Stoakes wrote: > The mmap_region() function is somewhat terrifying, with spaghetti-like > control flow and numerous means by which issues can arise and incomplete > state, memory leaks and other unpleasantness can occur. > > A large amount of the complexity arises from trying to handle errors late > in the process of mapping a VMA, which forms the basis of recently observed > issues with resource leaks and observable inconsistent state. > > This series goes to great lengths to simplify how mmap_region() works and > to avoid unwinding errors late on in the process of setting up the VMA for > the new mapping, and equally avoids such operations occurring while the VMA > is in an inconsistent state. > > The first four patches are intended for backporting to correct the > possibility of people encountering corrupted state while invoking mmap() > which is otherwise at risk of happening. > > After this we go further, refactoring the code, placing it in mm/vma.c in > order to make it eventually userland testable, and significantly > simplifying the logic to avoid this issue arising in future. Are the latter 4 patches thus also intended as hotfix for 6.12, or was it just due to git applying the same PATCH prefix to the whole series, and the real intention is 6.13? > Lorenzo Stoakes (8): > mm: avoid unsafe VMA hook invocation when error arises on mmap hook > mm: unconditionally close VMAs on error > mm: refactor map_deny_write_exec() > mm: resolve faulty mmap_region() error path behaviour > tools: testing: add additional vma_internal.h stubs > mm: insolate mmap internal logic to mm/vma.c > mm: refactor __mmap_region() > mm: do not attempt second merge for file-backed VMAs > > include/linux/mman.h | 21 +- > mm/internal.h | 44 ++++ > mm/mmap.c | 262 ++------------------ > mm/mprotect.c | 2 +- > mm/nommu.c | 7 +- > mm/vma.c | 403 ++++++++++++++++++++++++++++++- > mm/vma.h | 101 +------- > mm/vma_internal.h | 5 + > tools/testing/vma/vma_internal.h | 106 +++++++- > 9 files changed, 591 insertions(+), 360 deletions(-) > > -- > 2.47.0