Messages in this thread | | | From | Sasha Levin <> | Date | Fri, 30 Mar 2012 19:37:37 +0300 | Subject | Re: [PATCH] kmsg: Use vmalloc instead of kmalloc when writing |
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On Fri, Mar 30, 2012 at 6:30 PM, Greg KH <gregkh@linuxfoundation.org> wrote: > On Fri, Mar 30, 2012 at 01:04:27PM -0400, Sasha Levin wrote: >> There are no size checks in kmsg_write(), and we try allocating enough >> memory to store everything userspace gave us, which may be too much for >> kmalloc to allocate. > > Really? Have you seen this fail? As only root can do this, is this > really a problem?
Only root, and a whole bunch of management software that dumps data into /dev/kmsg (systemd and friends).
>> One option would be to limit it to something, but we can't come up with >> a number that would make sense. >> >> Instead, just use vmalloc so that nothing would break with large amounts >> of data. > > Are you sure this will work properly? Have you tested it with large > amounts of data?
My test was dumping 800mb of data into it, if there's anything else I should try please let me know.
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