Messages in this thread |  | | | Date | Sun, 08 Jun 2008 13:39:11 +0200 | | From | Thorsten Knabe <> | | Subject | Re: [BUG] Linux 2.6.25.4 task_struct leak |
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Jeff Dike wrote: > I misunderstood - I thought you were seeing a task_struct leak within > UML rather than a leak on the host elicited by UML. > >> As far as I understand the UML code in the kernel, an UML kernel uses >> some unusual clone() flags when creating new processes, which are seldom >> used by other applications and could be related to the bug. > > Yes, it does. I don't see the flags causing a leak, though. What > might be more likely (although I really have no idea) is ptrace. > Possibly a reference is held when it should have been dropped. This > might also show up with strace or gdb.
Hello Jeff.
Your assumption about ptrace causing the task_struct leak seems to be right. I bisected the problem down to a few commits using the repository at git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git.
Commit b7b71725fb9584454bfe5f231223bd63421798fb is the last known commit that does not leak task_structs, whereas commit a97f52e67890fda6b373c1c1895ff1c1c69b36c8 is leaking task_structs. Revisions in between do not even compile. Also I had to apply the changes from commit f9cb02b0be4de3c51edfdd701754e13d9a2d20d6 to most of the kernels I have tested, otherwise the UML process would crash on startup.
HTH Thorsten
-- ___ | | / E-Mail: linux@thorsten-knabe.de |horsten |/\nabe WWW: http://linux.thorsten-knabe.de
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