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authorDave Jones <davej@redhat.com>2006-09-29 01:59:51 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-29 09:18:10 -0700
commitaa83aa40ed2ae113d9ee5529cdd9e8c0e5fabe61 (patch)
tree08fa036a2793046528f84baebd3edf14272c5540
parent527063ba985740e9cd271731c31f503f916681c9 (diff)
downloadlinaro-lsk-aa83aa40ed2ae113d9ee5529cdd9e8c0e5fabe61.tar.gz
[PATCH] single bit flip detector
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. [akpm@osdl.org: cleanups] Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--mm/slab.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 792bfe320a8..3dbd6f4e747 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1683,10 +1683,32 @@ static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
static void dump_line(char *data, int offset, int limit)
{
int i;
+ unsigned char error = 0;
+ int bad_count = 0;
+
printk(KERN_ERR "%03x:", offset);
- for (i = 0; i < limit; i++)
+ for (i = 0; i < limit; i++) {
+ if (data[offset + i] != POISON_FREE) {
+ error = data[offset + i];
+ bad_count++;
+ }
printk(" %02x", (unsigned char)data[offset + i]);
+ }
printk("\n");
+
+ if (bad_count == 1) {
+ error ^= POISON_FREE;
+ if (!(error & (error - 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