On Fri, Feb 25, 2022 at 07:03:13PM +0100, Vlastimil Babka wrote:
> Hi,
>
> this series combines and revives patches from Oliver's last year
> bachelor thesis (where I was the advisor) that make SLUB's debugfs
> files alloc_traces and free_traces more useful.
> The resubmission was blocked on stackdepot changes that are now merged,
> as explained in patch 2.
>
> Patch 1 is a new preparatory cleanup.
>
> Patch 2 originally submitted here [1], was merged to mainline but
> reverted for stackdepot related issues as explained in the patch.
>
> Patches 3-5 originally submitted as RFC here [2]. In this submission I
> have omitted the new file 'all_objects' (patch 3/3 in [2]) as it might
> be considered too intrusive so I will postpone it for later. The docs
> patch is adjusted accordingly.
>
This problem is not caused by this patch series.
But I think it's worth mentioning...
It's really weird that some stack traces are not recorded
when CONFIG_KASAN=y.
I made sure that:
- Stack Depot did not reach its limit
- the free path happen on CONFIG_KASAN=y too.
I have no clue why this happen.
# cat dentry/free_traces (CONFIG_KASAN=y)
6585 <not-available> age=4294912647 pid=0 cpus=0
# cat dentry/free_traces (CONFIG_KASAN=n)
1246 <not-available> age=4294906877 pid=0 cpus=0
379 __d_free+0x20/0x2c age=33/14225/14353 pid=0-122 cpus=0-3
kmem_cache_free+0x1f4/0x21c
__d_free+0x20/0x2c
rcu_core+0x334/0x580
rcu_core_si+0x14/0x20
__do_softirq+0x12c/0x2a8
2 dentry_free+0x58/0xb0 age=14101/14101/14101 pid=158 cpus=0
kmem_cache_free+0x1f4/0x21c
dentry_free+0x58/0xb0
__dentry_kill+0x18c/0x1d0
dput+0x1c4/0x2fc
__fput+0xb0/0x230
____fput+0x14/0x20
task_work_run+0x84/0x17c
do_notify_resume+0x208/0x1330
el0_svc+0x6c/0x80
el0t_64_sync_handler+0xa8/0x130
el0t_64_sync+0x1a0/0x1a4
1 dentry_free+0x58/0xb0 age=7678 pid=190 cpus=1
kmem_cache_free+0x1f4/0x21c
dentry_free+0x58/0xb0
__dentry_kill+0x18c/0x1d0
dput+0x1c4/0x2fc
__fput+0xb0/0x230
____fput+0x14/0x20
task_work_run+0x84/0x17c
do_exit+0x2dc/0x8e0
do_group_exit+0x38/0xa4
__wake_up_parent+0x0/0x34
invoke_syscall+0x48/0x114
el0_svc_common.constprop.0+0x44/0xfc
do_el0_svc+0x2c/0x94
el0_svc+0x28/0x80
el0t_64_sync_handler+0xa8/0x130
el0t_64_sync+0x1a0/0x1a4
--
Thank you, You are awesome!
Hyeonggon :-)
