On 9/13/24 17:00, Hyeonggon Yoo wrote: > > >> On Sep 13, 2024, at 11:10 PM, Vlastimil Babka <vbabka@xxxxxxx> 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 <ruanjinjie@xxxxxxxxxx> 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 >> >>>> >>>> -- >>>> Hyeonggon > >
