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 <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 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 >> >> >
