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authorThomas Gleixner <tglx@linutronix.de>2008-02-20 23:57:30 +0100
committerIngo Molnar <mingo@elte.hu>2008-02-26 12:55:57 +0100
commitce28b9864b853803320c3f1d8de1b81aa4120b14 (patch)
treeb13268d3301eb70074dd38d8e92c1fab0f955114 /arch/m32r/boot
parentd4afe414189b098d56bcd24280c018aa2ac9a990 (diff)
x86: fix vsyscall wreckage
based on a report from Arne Georg Gleditsch about user-space apps misbehaving after toggling /proc/sys/kernel/vsyscall64, a review of the code revealed that the "NOP patching" done there is fundamentally unsafe for a number of reasons: 1) the patching code runs without synchronizing other CPUs 2) it inserts NOPs even if there is no clock source which provides vread 3) when the clock source changes to one without vread we run in exactly the same problem as in #2 4) if nobody toggles the proc entry from 1 to 0 and to 1 again, then the syscall is not patched out as a result it is possible to break user-space via this patching. The only safe thing for now is to remove the patching. This code was broken since v2.6.21. Reported-by: Arne Georg Gleditsch <arne.gleditsch@dolphinics.no> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/m32r/boot')
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