The patch titled
x86_64: fix boot hang due to nmi watchdog init code
has been added to the -mm tree. Its filename is
x86_64-fix-boot-hang-due-to-nmi-watchdog-init-code.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: x86_64: fix boot hang due to nmi watchdog init code
From: Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx>
2.6.19 stopped booting (or booted based on build/config) on our x86_64
systems due to a bug introduced in 2.6.19. check_nmi_watchdog schedules an
IPI on all cpus to busy wait on a flag, but fails to set the busywait flag
if NMI functionality is disabled.
This causes the secondary cpus to spin in an endless loop, causing the
kernel bootup to hang.
Depending upon the build, the busywait flag got overwritten (stack
variable) and caused the kernel to bootup on certain builds. Following
patch fixes the bug by setting the busywait flag before returning from
check_nmi_watchdog.
I guess using a stack variable is not good here as the calling function
could potentially return while the busy wait loop is still spinning on the
flag. I would think this is a good candidate for 2.6.19 stable as well.
Signed-off-by: Ravikiran Thirumalai <kiran@xxxxxxxxxxxx>
Signed-off-by: Shai Fultheim <shai@xxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/x86_64/kernel/nmi.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff -puN arch/x86_64/kernel/nmi.c~x86_64-fix-boot-hang-due-to-nmi-watchdog-init-code arch/x86_64/kernel/nmi.c
--- a/arch/x86_64/kernel/nmi.c~x86_64-fix-boot-hang-due-to-nmi-watchdog-init-code
+++ a/arch/x86_64/kernel/nmi.c
@@ -213,9 +213,10 @@ static __init void nmi_cpu_busy(void *da
}
#endif
+static int endflag = 0;
+
int __init check_nmi_watchdog (void)
{
- volatile int endflag = 0;
int *counts;
int cpu;
@@ -256,6 +257,7 @@ int __init check_nmi_watchdog (void)
if (!atomic_read(&nmi_active)) {
kfree(counts);
atomic_set(&nmi_active, -1);
+ endflag = 1;
return -1;
}
endflag = 1;
_
Patches currently in -mm which might be from kiran@xxxxxxxxxxxx are
x86_64-fix-boot-hang-due-to-nmi-watchdog-init-code.patch
mm-slab-eliminate-lock_cpu_hotplug-from-slab.patch
slab-leaks3-default-y.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
