On Fri, Jan 04, 2008 at 09:38:12PM +0400, Alexander Shaduri wrote: > > I got the following message, shortly followed by a system hang. > BUG: unable to handle kernel paging request at virtual address 48464443 > > (see the oops below).
AFAICS, it's quicklist_alloc() called from pgd_alloc(): static inline void *quicklist_alloc(int nr, gfp_t flags, void (*ctor)(void *)) { struct quicklist *q; void **p = NULL; q =&get_cpu_var(quicklist)[nr]; p = q->page; if (likely(p)) { q->page = p[0]; and we have q->page == 0x48464443. Seeing how we assign that sucker, that smells like we've got a page on quicklist with {0x43, 0x44, 0x46, 0x48} in its first 4 bytes. Instead of having address of the next page stored in there... Do other oopsen of the same kind give the same value? The shortest scenario I can see for that is * something accidentally frees a page * pgd_alloc() grabs it * pgd_free() releases it and puts on quicklist; the first 4 bytes are zeroed. * whatever used to hold that page modifies it, overwriting its beginning * next pgd_alloc() grabs that page and advances quicklist - sets it to the first 4 bytes of that page. At that point we are well and truly fucked - quicklist is corrupted and once we need more pgd we'll get that oops. The question is, what's losing and then overwriting that page in the first place? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/