Messages in this thread | | | Date | Wed, 14 Sep 2005 13:51:18 +0100 | From | Ian Collier <> | Subject | 2.6.13: More on drivers/block/loop.c |
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Vanilla 2.6.13 doesn't crash.
However, unpack a fresh copy of 2.6.13, edit include/linux/loop.h to change LO_KEY_SIZE from 32 to 1844, and *boom*. [Don't ask me why 1844... that's just what PPDD wants.]
It's crashing somewhere in loop_set_status_old, probably during the call to copy_from_user, but the crash messages aren't that helpful as they are different each time, often seem to happen during an interrupt, and usually contain pages of recursive calls to do_page_fault and error_code.
The loop_set_status_old function has two local variables, each of which is now 1812 bytes longer than it was, and I'm wondering if it's a stack overflow problem. How much stack is a kernel function allowed to use, anyway?
Replacing these variables with kmalloc'd pointers seems to stop the crashes anyway, so I'll pass that tip on to the PPDD folks.
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