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Mon, 14 Oct 2024 14:55:01 +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 NMEFNMUwDWcscAAAD6G6ig (envelope-from ); Mon, 14 Oct 2024 14:55:01 +0000 Message-ID: <7726cccb-78f8-4696-ac7e-57598c35576d@suse.cz> Date: Mon, 14 Oct 2024 16:55:01 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/slub: Avoid list corruption when removing a slab from the full list Content-Language: en-US To: David Rientjes , "yuan.gao" Cc: "Christoph Lameter (Ampere)" , penberg@kernel.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20241011102020.58087-1-yuan.gao@ucloud.cn> <572f7473-1781-388b-103e-d4382f58f2f9@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+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: <572f7473-1781-388b-103e-d4382f58f2f9@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 1A07E20013 X-Stat-Signature: peyra7kn8p8bnqkk7szkmsdbbyu8xcsb X-Rspam-User: X-HE-Tag: 1728917696-761289 X-HE-Meta: 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 IzX9YbeA XlOuF9tgSZNWOtHQ72paaGGCBLI7bwzo+SzS7fdK8cKW1JEU3qzg+mq6SsDlu/CtuoCn1/FmzmA2QQ3fIoziM9m9PLlSJCtPloRW9ZeNLbjGY4td4e/JMw1jr+4Z3aMDPI26Q5A21qD03QDJPIS2ym2aogAoML4JH30+j9JM7vClmZ8730aU9KZ8v9m5Y8/kSv0sERcBZcSnjg9WTng4bT4I26+2hZAQ+s78RXsnPvG4OTYjM7QJlEXcGyfPoY2Z5mpqAaCoolcKSApyHsfIaCZ39QAx7T9YCLN8tJoTshcE68mVwcY79IajSnXH3X2XIfJ5PVD0R/QelXXXcbDqcOTZpBmvcZMneTSyfDdXoev2glUMP4Am5yHY6z9uIgMjjlW3qc5+QWkyMXwA= 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 10/13/24 22:46, David Rientjes wrote: > On Sat, 12 Oct 2024, yuan.gao wrote: > >> On 24/10/11 11:07AM, Christoph Lameter (Ampere) wrote: >> > On Fri, 11 Oct 2024, yuan.gao wrote: >> > >> > > When an object belonging to the slab got freed later, the remove_full() >> > > function is called. Because the slab is neither on the partial list nor >> > > on the full list, it eventually lead to a list corruption. >> > >> > We detect list poison.... >> > >> > > diff --git a/mm/slab.h b/mm/slab.h >> > > index 6c6fe6d630ce..7681e71d9a13 100644 >> > > --- a/mm/slab.h >> > > +++ b/mm/slab.h >> > > @@ -73,6 +73,10 @@ struct slab { >> > > struct { >> > > unsigned inuse:16; >> > > unsigned objects:15; >> > > + /* >> > > + * Reuse frozen bit for slab with debug enabled: >> > >> > "If slab debugging is enabled then the frozen bit can bereused to >> > indicate that the slab was corrupted" >> > >> > > index 5b832512044e..b9265e9f11aa 100644 >> > > --- a/mm/slub.c >> > > +++ b/mm/slub.c >> > > @@ -1423,6 +1423,11 @@ static int check_slab(struct kmem_cache *s, struct slab *slab) >> > > slab->inuse, slab->objects); >> > > return 0; >> > > } >> > > + if (slab->frozen) { >> > > + slab_err(s, slab, "Corrupted slab"); >> > >> > >> > "Slab folio disabled due to metadata corruption" ? >> > >> > >> >> Yes, that's what I meant. >> Perhaps I should change the description from "Corrupted slab" to >> "Metadata corrupt"? >> > > I think the point here is that slab page corruption is different from slab > metadata corruption :) > > The suggested phrasing, "Slab folio disabled due to metadata corruption", > sounds good to me. What about: "Slab disabled due to previous consistency check failure" ? > >> > > @@ -2744,7 +2750,10 @@ static void *alloc_single_from_partial(struct kmem_cache *s, >> > > slab->inuse++; >> > > >> > > if (!alloc_debug_processing(s, slab, object, orig_size)) { >> > > - remove_partial(n, slab); >> > > + if (folio_test_slab(slab_folio(slab))) { Your patch adds add_full() here as in the previous versions. I wouldn't do it anymore. Thanks to the frozen bit check in check_slab(), no further list manipulation should happen that would trigger the list poison being detected. Adding to full list would rather mean each sysfs-triggered validation will reach the slab and output the new slab_err() message, which is not useful. We want the corrupted slab to stay away from everything else, and only be informed of further object freeing attempts. >> > >> > >> > Does folio_test_slab test for the frozen bit?? >> > >> >> For slab folios, slab->fronzen has been set to 1. >> For non-slab folios, we should not call remove_partial(). >> I'm not sure if I understand this correctly. >> >> Thanks >>