path: root/security
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authorYury Polyanskiy <ypolyans@princeton.edu>2010-05-24 14:33:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-25 08:07:02 -0700
commit940370fc86b920b51a34217a1facc3e9e97c2456 (patch)
tree6d53529bc158408c42df40d78ee728adb399f787 /security
parentb3b77c8caef1750ebeea1054e39e358550ea9f55 (diff)
hangcheck-timer: fix x86_32 bugs
drivers/char/hangcheck-timer.c is doubly broken. When the overflown value of TIMER_FREQ is abnormally low, it spams the syslog with KERN_CRIT messages "Hangcheck: hangcheck value past margin!" But whether it happens or not depends on HZ and lpj in a complex way. People have hit it occasionally as far as google search can tell. First, the following line overflows unsigned long: # define TIMER_FREQ (HZ*loops_per_jiffy) Second, and more importantly, loops_per_jiffy has little to do with the con= version from the the time scale of get_cycles() (aka rdtsc) to the time scale of jiffies. The attached patch resolves both of the problems. Acked-by: Joel Becker <joel.becker@oracle.com> Cc: john stultz <johnstul@us.ibm.com> Cc: Jan Glauber <jan.glauber@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security')
0 files changed, 0 insertions, 0 deletions