[Bug 233306] panic when using userppp

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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233306

lenzi.sergio at gmail.com changed:

           What    |Removed                     |Added
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 Attachment #199339|0                           |1
        is obsolete|                            |

--- Comment #3 from lenzi.sergio at gmail.com ---
Created attachment 199511
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=199511&action=edit
remove code that panics the system due to invalid memory access

The panic happens when the code:  both i386 and amd64
info.rti_info[RTAX_IFP] = rt->rt_ifp->if_addr->ifa_addr;
at /usr/src/sys/net/rtsock.c near line 1568  the code tries to access
rt->rt_ifp->if_addr->ifa_addr, but because rt->rt_ifp points to an already
freed memory, and the pointer is NOT NULL, probably because the free code does
not nulls the pointer. or a race condition in the code, the system panics at
page fault in kernel mode

The patch removes the line from the rtsock.c for a while until some guru tracks
the race condition or fixes the pointer to a null value after rt->rt_ifp is
freed and so a test can be done..

the server in test holds many (100+) pppoi connections that changes every time,
the server runs routed with flags=-s so the route tables are stressed in
add/delete routes all the time... sometimes it panics in seconds, sometimes
after hours...  Now with this patch, it is working 24/7  for some days...

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