Messages in this thread | | | Date | Sun, 9 Mar 2003 01:12:13 -0500 | From | Ion Badulescu <> | Subject | Re: [NFS] Race in rpc_delete_timer causes crash |
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On Sun, 9 Mar 2003 00:03:45 +0100 (MET), Ulrich Weigand <weigand@immd1.informatik.uni-erlangen.de> wrote: > Hello, > > we're seeing a rare and hard to trigger crash on s390 where rpc_run_timer > calls via an invalid callback pointer.
Myself and Jakob Oestergaard have seen the same race, and the tentative fix from Trond was similar to yours. I haven't been able to reproduce the problem after applying that fix.
Perhaps it's time to propagate the patch upstream? Most recent 2.4.x kernels are affected...
> What appears to happen is that rpc_call_sync allocates a struct rpc_task > (with its embedded tk_timer) on the stack, and the timer gets set up > sometime during rpc_execute. However, the timer actually triggers at > a point in time where the original call to rpc_call_sync has already > returned, and the stack space overwritten by other data. That data is > now interpreted as an rpc_task struct holding a tk_timeout_fn pointer by > rpc_run_timer, which causes the Oops (actually, Aieee).
Yup, that's the race all right.
Ion
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