The patch titled
single bit flip detector
has been added to the -mm tree. Its filename is
single-bit-flip-detector.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: single bit flip detector
From: Dave Jones <davej@xxxxxxxxxx>
In cases where we detect a single bit has been flipped, we spew the usual
slab corruption message, which users instantly think is a kernel bug. In a
lot of cases, single bit errors are down to bad memory, or other hardware
failure.
This patch adds an extra line to the slab debug messages in those cases, in
the hope that users will try memtest before they report a bug.
000: 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Single bit error detected. Possibly bad RAM. Run memtest86.
Signed-off-by: Dave Jones <davej@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
diff -puN mm/slab.c~single-bit-flip-detector mm/slab.c
--- a/mm/slab.c~single-bit-flip-detector
+++ a/mm/slab.c
@@ -1637,10 +1637,28 @@ static void poison_obj(struct kmem_cache
static void dump_line(char *data, int offset, int limit)
{
int i;
+ unsigned char total = 0, bad_count = 0, errors;
printk(KERN_ERR "%03x:", offset);
- for (i = 0; i < limit; i++)
+ for (i = 0; i < limit; i++) {
+ if (data[offset + i] != POISON_FREE) {
+ total += data[offset + i];
+ bad_count++;
+ }
printk(" %02x", (unsigned char)data[offset + i]);
+ }
printk("\n");
+
+ if (bad_count == 1) {
+ errors = total ^ POISON_FREE;
+ if (errors && !(errors & (errors-1))) {
+ printk(KERN_ERR "Single bit error detected. Probably bad RAM.\n");
+#ifdef CONFIG_X86
+ printk(KERN_ERR "Run memtest86+ or a similar memory test tool.\n");
+#else
+ printk(KERN_ERR "Run a memory test tool.\n");
+#endif
+ }
+ }
}
#endif
_
Patches currently in -mm which might be from davej@xxxxxxxxxx are
git-agpgart.patch
git-cpufreq.patch
remove-null-chars-from-dvb-names.patch
remove-silly-messages-from-input-layer.patch
git-kbuild.patch
via-sata-oops-on-init.patch
tickle-nmi-watchdog-on-serial-output.patch
improve-machzwd-detection.patch
debug-variants-of-linked-list-macros.patch
tty_ioc-keep-davej-sane.patch
single-bit-flip-detector.patch
sched-dont-print-migration-cost-when-only-1-cpu.patch
fbcon-use-persistent-allocation-for-cursor-blinking.patch
post-halloween-doc.patch
single-bit-flip-detector-tidy.patch
-
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