From: Michal Hocko <mhocko@kernel.org>
To: Sami Farin <hvtaifwkbgefbaei@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [BUG] How to crash 4.9.2 x86_64: vmscan: shrink_slab
Date: Tue, 10 Jan 2017 10:22:41 +0100 [thread overview]
Message-ID: <20170110092241.GA28032@dhcp22.suse.cz> (raw)
In-Reply-To: <20170109210210.2zgvw6nfs4qbgmjw@m.mifar.in>
On Mon 09-01-17 23:02:10, Sami Farin wrote:
> # sysctl vm.vfs_cache_pressure=-100
>
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6640827866535449472
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6640827866535450112
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-661702561611775889
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6640827866535442432
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6562613194205300197
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6640827866535439872
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-659655090764208789
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6564660665198832072
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6562613194351275164
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6562615996648922728
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6564660665198832072
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-6562613194351264981
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-569296135781119076
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-565206492037048430
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-565212096665106188
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-569296135781119076
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-565206492037043196
> kernel: vmscan: shrink_slab: super_cache_scan+0x0/0x1a0 negative objects to delete nr=-659660388715270673
>
>
> Alternatively,
> # sysctl vm.vfs_cache_pressure=10000000
Both values are insane and admins do not do insane things to their
machines, do they?
I am not sure how much we want to check the input value. -100 is clearly
bogus and
.procname = "vfs_cache_pressure",
.data = &sysctl_vfs_cache_pressure,
.maxlen = sizeof(sysctl_vfs_cache_pressure),
.mode = 0644,
.proc_handler = &proc_dointvec,
.extra1 = &zero,
tries to enforce min (extra1) check except proc_dointvec doesn't care
about this... This is news to me. Only proc_dointvec_minmax does care
about extra*, it seems.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-01-10 9:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-09 21:02 Sami Farin
2017-01-10 9:22 ` Michal Hocko [this message]
2017-01-10 10:32 ` Sami Farin
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