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From: Emiliano Gabrielli <Emiliano.Gabrielli@roma2.infn.it>
To: tlan@zet.no, linux-kernel@vger.kernel.org
Subject: Re: Kernel BUG at swap.c:62 [2.4.19 vanilla]
Date: Wed, 16 Oct 2002 16:38:45 +0200
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On 15:01, mercoledì 16 ottobre 2002, Thomas Langås wrote:
> Reading Oops report from the terminal
> kernel BUG at swap.c:62!
> kernel BUG at swap.c:62!
> invalid operand: 0000
> CPU:    1
> EIP:    0010:[<c01329ca>]    Not tainted
> EFLAGS: 00010202
> invalid operand: 0000

>
> This is a vanilla 2.4.19 kernel, and we've seen this bug on several
> machines, but we haven't been able to find out what triggers it. And I
> don't see a BUG-statement at swap.c line 62.  So, anyone with an idea of
> what to do is welcome with suggestions :)

well, the BUG() is inplicit in add_page_to_inactive_list in linux.c:61, this 
macro is defined in linux/swap.h:197.

Could this one is a patch ?!?:

@linux/swap.h
#define DEBUG_LRU_PAGE(page)                    \
do {                                            \
-        if (!PageLRU(page))                     \
-                BUG();                          \
-        if (PageActive(page))                   \
-                BUG();                          \
+        BUG_ON(!PageLRU(page))                  \
+        BUG_ON (PageActive(page))               \
} while (0)

@mm/swap.c
void lru_cache_add(struct page * page)
{
+        spin_lock(&pagemap_lru_lock);
        if (!TestSetPageLRU(page)) {
-        spin_lock(&pagemap_lru_lock);
	add_page_to_inactive_list(page);
-        spin_unlock(&pagemap_lru_lock);
        }
+        spin_unlock(&pagemap_lru_lock);
}

best reguards 

Emiliano 'AlberT' Gabrielli