cvs commit: src/sys/netinet ip_dummynet.c

Ruslan Ermilov ru at
Fri Feb 3 08:11:32 PST 2006

On Fri, Feb 03, 2006 at 11:38:19AM +0000, Gleb Smirnoff wrote:
> glebius     2006-02-03 11:38:19 UTC
>   FreeBSD src repository
>   Modified files:
>     sys/netinet          ip_dummynet.c 
>   Log:
>   Dropping the lock in the transmit_event() is not safe, because we
>   store some pipe pointers on stack. If user reconfigures dummynet
>   in the interlock gap, we can work with freed pipes after relock.
>   To fix this, we decided not to send packets in transmit_event(),
>   but fill a queue. At the end of dummynet() and dummynet_io(),
>   after the lock is dropped, if there is something in the queue
>   we run dummynet_send() to process the queue.
>   In collaboration with:  ru
>   Revision  Changes    Path
>   1.98      +115 -94   src/sys/netinet/ip_dummynet.c
The insufficient locking resulted in a "NULL-like" pointer dereference.
Fault virtual address was 0x18: NULL + 8 (sizeof of a pointer on amd64)
+ 0x10 (structure offset).

Thanks for providing the fix so quickly and for working over night!

Ruslan Ermilov
ru at
FreeBSD committer
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