This Linux kernel change "watchdog: Improve initialisation error message and documentation" is included in the Linux 2.6.37 release. This change is authored by Ben Hutchings <ben [at] decadent.org.uk> on Sun Jan 2 23:02:42 2011 +0000. The commit for this change in Linux stable tree is 5514237 (patch).
watchdog: Improve initialisation error message and documentation The error message 'NMI watchdog failed to create perf event...' does not make it clear that this is a fatal error for the watchdog. It also currently prints the error value as a pointer, rather than extracting the error code with PTR_ERR(). Fix that. Add a note to the description of the 'nowatchdog' kernel parameter to associate it with this message. Reported-by: Cesare Leonardi <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> Cc: [email protected] Cc: [email protected] Cc: Don Zickus <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: <[email protected]> # .37.x and later LKML-Reference: <[email protected]> Signed-off-by: Ingo Molnar <[email protected]>
There are 5 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.
Documentation/kernel-parameters.txt | 2 +- kernel/watchdog.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 8b61c93..01ece1b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1759,7 +1759,7 @@ and is between 256 and 4096 characters. It is defined in the file nousb [USB] Disable the USB subsystem - nowatchdog [KNL] Disable the lockup detector. + nowatchdog [KNL] Disable the lockup detector (NMI watchdog). nowb [ARM] diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 6e3c41a..5b08215 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -364,7 +364,8 @@ static int watchdog_nmi_enable(int cpu) goto out_save; } - printk(KERN_ERR "NMI watchdog failed to create perf event on cpu%i: %pn", cpu, event); + printk(KERN_ERR "NMI watchdog disabled for cpu%i: unable to create perf event: %ldn", + cpu, PTR_ERR(event)); return PTR_ERR(event); /* success path */