Re: [Crash-utility] [PATCH] SLUB: Fix for offset change of struct slab members on Linux 6.2-rc1

On Mon, Dec 26, 2022 at 12:42 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab(a)nec.com&gt; wrote: > On 2022/12/22 16:50, lijiang wrote: >> After applying the patch, I got another error based on the latest kernel >> commit 9d2f6060fe4c3b49d0cdc1dce1c99296f33379c8: >> >> crash> kmem -S filp >> CACHE OBJSIZE ALLOCATED TOTAL SLABS SSIZE NAME >> ffff9d80c030a100 232 1125 3936 123 8k filp >> CPU 0 KMEM_CACHE_CPU: >> ffff9d81e7a38470 >> CPU 0 SLAB: >> SLAB MEMORY NODE TOTAL ALLOCATED FREE >> fffff0f3841a7700 ffff9d80c69dc000 0 32 10 22 >> FREE / [ALLOCATED] >> kmem: filp: slab: fffff0f3841a7700 invalid freepointer: 4404c55079ecb7fe >> CPU 1 KMEM_CACHE_CPU: >> ffff9d81e7a78470 >> CPU 1 SLAB: >> SLAB MEMORY NODE TOTAL ALLOCATED FREE >> fffff0f38446a600 ffff9d80d1a98000 0 32 0 32 >> FREE / [ALLOCATED] >> ... >> >> And this issue can not always be reproduced, I have tested it more than > ten >> times, the above error can be observed on my side, maybe one or two > times. >> >> But anyway, I'm curious if this is another issue. Could you please also >> double check it? > > Thank you for testing. > > I have not reproduced it with kdump, but did it with live system when > repeating this: > > crash> kmem -S > /tmp/kmem-S > crash> kmem -S > /tmp/kmem-S > ... > crash> kmem -S > /tmp/kmem-S > kmem: kmalloc-16: slab: ffffdb3bc440bcc0 invalid freepointer: > d3ec64863a077e7c > > As you say, it does not always happen, so it will be a timing issue or > corner case. Maybe there was a change in managing freepointer list, > but so far I'm not sure what the cause is. > > Theoretically, this issue can also be reproduced on kdump at a certain time point. > Anyway, I think it's not due to the offset change of slab.slab_list and > not the same issue. Can we apply this and look into it later? > > Yes, I agree that it might be another issue. Let's leave it there. For the patch: Ack.