From 86f343b50bb9f56cce60fade22da9defff28934c Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 21 Sep 2012 10:41:50 -0700 Subject: rcu: Fix CONFIG_RCU_FAST_NO_HZ stall warning message The print_cpu_stall_fast_no_hz() function attempts to print -1 when the ->idle_gp_timer is not pending, but unsigned arithmetic causes it to instead print ULONG_MAX, which is 4294967295 on 32-bit systems and 18446744073709551615 on 64-bit systems. Neither of these are the most reader-friendly values, so this commit instead causes "timer not pending" to be printed when ->idle_gp_timer is not pending. Reported-by: Paul Walmsley Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- Documentation/RCU/stallwarn.txt | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'Documentation/RCU') diff --git a/Documentation/RCU/stallwarn.txt b/Documentation/RCU/stallwarn.txt index 523364e4e1f..1927151b386 100644 --- a/Documentation/RCU/stallwarn.txt +++ b/Documentation/RCU/stallwarn.txt @@ -99,7 +99,7 @@ In kernels with CONFIG_RCU_FAST_NO_HZ, even more information is printed: INFO: rcu_preempt detected stall on CPU - 0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 drain=0 . timer=-1 + 0: (64628 ticks this GP) idle=dd5/3fffffffffffffff/0 drain=0 . timer not pending (t=65000 jiffies) The "(64628 ticks this GP)" indicates that this CPU has taken more @@ -116,13 +116,13 @@ number between the two "/"s is the value of the nesting, which will be a small positive number if in the idle loop and a very large positive number (as shown above) otherwise. -For CONFIG_RCU_FAST_NO_HZ kernels, the "drain=0" indicates that the -CPU is not in the process of trying to force itself into dyntick-idle -state, the "." indicates that the CPU has not given up forcing RCU -into dyntick-idle mode (it would be "H" otherwise), and the "timer=-1" -indicates that the CPU has not recented forced RCU into dyntick-idle -mode (it would otherwise indicate the number of microseconds remaining -in this forced state). +For CONFIG_RCU_FAST_NO_HZ kernels, the "drain=0" indicates that the CPU is +not in the process of trying to force itself into dyntick-idle state, the +"." indicates that the CPU has not given up forcing RCU into dyntick-idle +mode (it would be "H" otherwise), and the "timer not pending" indicates +that the CPU has not recently forced RCU into dyntick-idle mode (it +would otherwise indicate the number of microseconds remaining in this +forced state). Multiple Warnings From One Stall -- cgit v1.2.3-70-g09d2