Messages in this thread | | | From | (Eric W. Biederman) | Subject | Re: Hung task when calling clone() due to netfilter/slab | Date | Fri, 20 Jan 2012 12:40:32 -0800 |
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Christoph Lameter <cl@linux.com> writes:
> On Thu, 19 Jan 2012, Eric W. Biederman wrote: > >> On the flip side removing from sysfs with locks held must be done >> carefully, and as a default I would recommend not to hold locks over >> removing things from sysfs. As removal blocks waiting for all of the >> callers into sysfs those sysfs attributes to complete. >> >> It looks like you are ok on the removal because none of the sysfs >> attributes appear to take the slub_lock, just /proc/slabinfo. But >> it does look like playing with fire. > > Ok then I guess my last patch is needed to make sysfs operations safe. > > It may be good to audit the kernel for locks being held while calling > sysfs functions. Isnt there a lockdep check that ensures that no locks are > held?
I don't see a no locks are held check but call_usermodehelper in the blocking case could certainly use one.
For the sysfs remove case lockdep should work.
Eric
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