path: root/mm/slab_common.c
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authorTony Luck <>2014-07-18 18:43:01 (GMT)
committerGreg Kroah-Hartman <>2014-07-31 19:53:49 (GMT)
commitefd39f7786aa4e7a847d5f8c9f5506e3b9ad6b38 (patch)
treed00cfd1c992b677c0b30b6dda758e5440ab482cb /mm/slab_common.c
parentcebdb6fa24dfd48af3bba1af6ba485b45430fb1c (diff)
tracing: Fix wraparound problems in "uptime" trace clock
commit 58d4e21e50ff3cc57910a8abc20d7e14375d2f61 upstream. The "uptime" trace clock added in: commit 8aacf017b065a805d27467843490c976835eb4a5 tracing: Add "uptime" trace clock that uses jiffies has wraparound problems when the system has been up more than 1 hour 11 minutes and 34 seconds. It converts jiffies to nanoseconds using: (u64)jiffies_to_usecs(jiffy) * 1000ULL but since jiffies_to_usecs() only returns a 32-bit value, it truncates at 2^32 microseconds. An additional problem on 32-bit systems is that the argument is "unsigned long", so fixing the return value only helps until 2^32 jiffies (49.7 days on a HZ=1000 system). Avoid these problems by using jiffies_64 as our basis, and not converting to nanoseconds (we do convert to clock_t because user facing API must not be dependent on internal kernel HZ values). Link: Fixes: 8aacf017b065 "tracing: Add "uptime" trace clock that uses jiffies" Signed-off-by: Tony Luck <> Signed-off-by: Steven Rostedt <> Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'mm/slab_common.c')
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