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Fri, 25 Oct 2024 10:10:50 +0800 Message-ID: <511392f2-8e94-d2fc-63a6-ac3b4cac10e1@huawei.com> Date: Fri, 25 Oct 2024 10:10:49 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.0 Subject: Re: [PATCH v4 3/3] mm/slub: Fix memory leak of kobj->name in sysfs_slab_add() Content-Language: en-US To: Vlastimil Babka , Hyeonggon Yoo <42.hyeyoo@gmail.com> CC: Liu Shixin , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Linux Memory Management List , LKML References: <20221112114602.1268989-1-liushixin2@huawei.com> <20221112114602.1268989-4-liushixin2@huawei.com> <3780a622-03f2-4cfe-5705-0e9d0be61d57@huawei.com> <68b86f66-cd00-bb7d-b8bb-5a94e8dd1ea2@huawei.com> <02820eb8-0b8f-4aa8-9315-85368e9c331e@suse.cz> <0F94364A-F0C8-4C0A-B38D-3DDEA653B6B7@gmail.com> <7707ff34-16e1-4f8c-9af6-8b5b6591c77e@suse.cz> From: Jinjie Ruan In-Reply-To: <7707ff34-16e1-4f8c-9af6-8b5b6591c77e@suse.cz> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.109.254] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemg200008.china.huawei.com (7.202.181.35) X-Rspam-User: X-Stat-Signature: 9puppqzonzg44oqf8qdgpymd1qgm6osa X-Rspamd-Queue-Id: 3097680002 X-Rspamd-Server: rspam11 X-HE-Tag: 1729822220-924680 X-HE-Meta: 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 A7ABA75C Muxu4nnWg4PYlln/7d71okhAGREK1tbOqFtmY/8D3XUNZw9mDv9mL0Ii4i8EBAmGGK8/hCTg872t5Sb7T66jaw5sJTDfTmPDWrLaqnOqiRPGRx6bHQewUXm9jz3pp4ek2mUjNW9SqH1aX1w531kFFJf4ayuE/k32Twpzf+7PdsKtTT83ErdcpYC4YIWsFUO/y0c0GIKNwayvFmjF4j/HYah1NAcyqrfDkMYbuE0WfTey1TNZxXdBKMY/tMt8VdYCXfe+EZdd+GsGA4S2WqTHT3Wxrddn8Wfj3jR7ETbWh3VZlrcFNU1yVHlYoS1jPyzR1MH7CIoCbc7juWr8= 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 2024/10/2 19:35, Vlastimil Babka wrote: > On 9/13/24 17:00, Hyeonggon Yoo wrote: >> >> >>> On Sep 13, 2024, at 11:10 PM, Vlastimil Babka wrote: >>> >>> On 9/6/24 10:10, Jinjie Ruan wrote: >>>> >>>> >>>> On 2024/9/5 21:59, Hyeonggon Yoo wrote: >>>>> On Thu, Sep 5, 2024 at 12:41 PM Jinjie Ruan wrote: >>>>>> >>>>>> >>>>>> >>>>>> On 2022/11/12 19:46, Liu Shixin wrote: >>>>>>> There is a memory leak of kobj->name in sysfs_slab_add(): >>>>>>> >>>>>>> unreferenced object 0xffff88817e446440 (size 32): >>>>>>> comm "insmod", pid 4085, jiffies 4296564501 (age 126.272s) >>>>>>> hex dump (first 32 bytes): >>>>>>> 75 62 69 66 73 5f 69 6e 6f 64 65 5f 73 6c 61 62 ubifs_inode_slab >>>>>>> 00 65 44 7e 81 88 ff ff 00 00 00 00 00 00 00 00 .eD~............ >>>>>>> backtrace: >>>>>>> [<000000005b30fbbd>] __kmalloc_node_track_caller+0x4e/0x150 >>>>>>> [<000000002f70da0c>] kstrdup_const+0x4b/0x80 >>>>>>> [<00000000c6712c61>] kobject_set_name_vargs+0x2f/0xb0 >>>>>>> [<00000000b151218e>] kobject_init_and_add+0xb0/0x120 >>>>>>> [<00000000e56a4cf5>] sysfs_slab_add+0x17d/0x220 >>>>>>> [<000000009326fd57>] __kmem_cache_create+0x406/0x590 >>>>>>> [<00000000dde33cff>] kmem_cache_create_usercopy+0x1fc/0x300 >>>>>>> [<00000000fe90cedb>] kmem_cache_create+0x12/0x20 >>>>>>> [<000000007a6531c8>] 0xffffffffa02d802d >>>>>>> [<000000000e3b13c7>] do_one_initcall+0x87/0x2a0 >>>>>>> [<00000000995ecdcf>] do_init_module+0xdf/0x320 >>>>>>> [<000000008821941f>] load_module+0x2f98/0x3330 >>>>>>> [<00000000ef51efa4>] __do_sys_finit_module+0x113/0x1b0 >>>>>>> [<000000009339fbce>] do_syscall_64+0x35/0x80 >>>>>>> [<000000006b7f2033>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 >>>>>> >>>>>> >>>>>> Hi，every one, >>>>> >>>>> Hi. >>>>> >>>>>> I found the same problem and it solve this problem with the patch, is >>>>>> there any plan to update the patch and solve it. >>> >>> Hmm looks like back in 2022, Hyeonggon had some feedback to the series which >>> was not answered and then it got forgotten. Feel free to take over and send >>> an updated version. >> >> >> I was thinking of what the fix would be with my feedback, >> and I still think passing different kobj_type (with a dummy release function) for early kmem_caches >> will be a more appropriate approach. >> >> However, there is one concern: people that wrote kobject.rst might not like it :( >> >> in Documentation/core-api/kobject.rst: >>> One important point cannot be overstated: every kobject must have a release() method, >>> and the kobject must persist (in a consistent state) until that method is called. If these constraints are not met, >>> the code is flawed. Note that the kernel will warn you if you forget to provide a release() method. >>> Do not try to get rid of this warning by providing an "empty" release function. >> >> But obviously we don't want to release caches just because the kernel failed to add it to sysfs. >> >>>>> What kernel version do you use, >>>> >>>> 6.11.0-rc6 >>>> >>>>> and when do you encounter it or how do you reproduce it? >>>> >>>> Hi, Hyeonggon, >>>> >>>> Thank you, I encounter it when doing inject fault test while modprobe >>>> amdgpu.ko. >>> >>> So I wonder where's the problem that results in kobject_init_and_add() >>> failing. If it's genuinely duplicate name as commit 80da026a8e5d suggests, >>> 6.12-rc1 will have a warning to prevent that. Delayed destruction of >>> SLAB_TYPESAFE_BY_RCU caches should also no longer happen with 6.12-rc1. So >>> worth retrying with that and if it's still failing, we should look at the >>> root cause perhaps. >> >> I thought it was because the memory allocation for a name string failed due to fault injection? > > Well in any case 6.12-rc1 introduced a new one, fixed by: > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab.git/commit/?h=slab/for-6.12-rc1/fixes&id=77ced98f0f03fdc196561d1afbe652899c318073 > > So once that's mainline, we can see if anything remains Using the newest 6.12.0-rc4, the issue still exists in slab: unreferenced object 0xffffff80ce6da9c0 (size 16): comm "modprobe", pid 12782, jiffies 4299073226 hex dump (first 16 bytes): 6f 76 6c 5f 69 6e 6f 64 65 00 6d ce 80 ff ff ff ovl_inode.m..... backtrace (crc 1a460899): [<00000000edf3be8b>] kmemleak_alloc+0x34/0x40 [<0000000004121c8d>] __kmalloc_node_track_caller_noprof+0x304/0x3e8 [<00000000515e9eda>] kstrdup+0x48/0x84 [<000000005d2d0c1a>] kstrdup_const+0x34/0x40 [<00000000d14076ce>] kvasprintf_const+0x170/0x1e0 [<0000000060f79972>] kobject_set_name_vargs+0x5c/0x12c [<00000000299f544a>] kobject_init_and_add+0xd4/0x168 [<000000008ceb40f4>] sysfs_slab_add+0x190/0x21c [<00000000027371b9>] do_kmem_cache_create+0x354/0x5cc [<00000000cc9eb2aa>] __kmem_cache_create_args+0x1b8/0x2c8 [<000000006a3e21cc>] 0xffffffea545a409c [<0000000002f945b3>] do_one_initcall+0x110/0x77c [<0000000024f23211>] do_init_module+0x1dc/0x5c8 [<00000000a16337d6>] load_module+0x4acc/0x4e90 [<00000000be447e77>] init_module_from_file+0xd4/0x128 [<0000000048065de1>] idempotent_init_module+0x2d4/0x57c > >>> >>>>> >>>>> -- >>>>> Hyeonggon >> >> >