Messages in this thread | | | Date | Tue, 14 Dec 2010 17:03:13 +0100 | From | Tejun Heo <> | Subject | Re: [RFC] [Patch 0/21] Non disruptive application core dump infrastructure |
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Hello,
On 12/14/2010 04:49 PM, Linus Torvalds wrote: > On Tue, Dec 14, 2010 at 1:52 AM, Suzuki K. Poulose <suzuki@in.ibm.com> wrote: >> >> This is series of patches implementing an infrastructure for capturing the core >> of an application without disrupting its process semantics. >> >> The infrastructure makes use of the freezer subsystem in kernel to freeze the >> threads and then collect the information to generate the core. > > This seems to be a fundamentally flawed approach. > >>From a security standpoint, it looks like a total disaster. A frozen > process is really hard to get rid of, so it looks like an obvious DoS > attack to just create lots of processes, then sneakily freeze them > all, and then laugh at the poor system admin who has no idea what's > going on. While frozen, the things are basically unkillable but look > entirely normal, no?
I think a better way would be adding a ptrace attach which is nestable and doesn't have the nasty side effect caused by the interactions between the implicit SIGSTOP and group stop. As a preparation step, I posted a patchset to cleanup the interactions between ptrace and group stop which is being reviewed. Once we have a nestable ptrace attach, we should be able to simply adapt gcore(1) to use it and write out core dump from userland.
Thanks.
-- tejun
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