Messages in this thread | | | Date | Thu, 05 Nov 2009 15:51:15 -0800 | From | "H. Peter Anvin" <> | Subject | /proc/sys/kernel/pty/nr broken, possibly since 2.6.28 |
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I just noticed that /proc/sys/kernel/pty/nr is broken, and the most likely culprit seems to be the series of checkins that include 8b0a88d5 and bf970ee4, during the 2.6.28 merge window. This is thus a regression. I haven't verified that the bug really goes that far back -- I should do a bisection -- but it is at least present in 2.6.30.9 and 2.6.32-rc6.
The symptom is that /proc/sys/kernel/pty/nr is properly increased, but never decreased when a pty gets dropped. It is in fact rather trivial to escalate /proc/sys/kernel/pty/nr far above /proc/sys/kernel/pty/max.
As far as I read this series, the indent was to have this accounting handled in pty_unix98_remove(), however, it would appear that that function never gets called. I'm wondering if this may be a symptom of a bigger problem as well.
-hpa
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