Re: Oops with 2.4.0-test13pre3 - swapoff

From: Christoph Rohland (cr@sap.com)
Date: Fri Dec 22 2000 - 05:31:28 EST


Marcelo Tosatti <marcelo@conectiva.com.br> writes:

> Christoph is already looking at it and should have a fix soon.

Here it comes against 13-pre4 ...

We cannot call delete_from_swap_cache, it was called already in
try_to_unuse.

There is still a race when we page in the page which is
just freed in try_to_unuse. I am not sure how to fix this.

Also the add_to_page_cache forgot the offset :-(

Greetings
                Christoph

--- 4-13-4/mm/shmem.c Fri Dec 22 10:05:38 2000
+++ m4-13-4/mm/shmem.c Fri Dec 22 10:47:11 2000
@@ -761,14 +761,16 @@
         swp_entry_t **base, **ptr;
         unsigned long idx;
         int offset;
+ struct shmem_inode_info *info = &inode->u.shmem_i;
         
         idx = 0;
- if ((offset = shmem_clear_swp (entry, inode->u.shmem_i.i_direct, SHMEM_NR_DIRECT)) >= 0)
+ spin_lock (&info->lock);
+ if ((offset = shmem_clear_swp (entry,info->i_direct, SHMEM_NR_DIRECT)) >= 0)
                 goto found;
 
         idx = SHMEM_NR_DIRECT;
- if (!(base = inode->u.shmem_i.i_indirect))
- return 0;
+ if (!(base = info->i_indirect))
+ goto out;
 
         for (ptr = base; ptr < base + ENTRIES_PER_PAGE; ptr++) {
                 if (*ptr &&
@@ -776,16 +778,16 @@
                         goto found;
                 idx += ENTRIES_PER_PAGE;
         }
+out:
+ spin_unlock (&info->lock);
         return 0;
 found:
- delete_from_swap_cache (page);
- add_to_page_cache (page, inode->i_mapping, idx);
+ add_to_page_cache (page, inode->i_mapping, offset + idx);
         SetPageDirty (page);
         SetPageUptodate (page);
         UnlockPage (page);
- spin_lock (&inode->u.shmem_i.lock);
- inode->u.shmem_i.swapped--;
- spin_unlock (&inode->u.shmem_i.lock);
+ info->swapped--;
+ spin_unlock (&info->lock);
         return 1;
 }
 

-
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This archive was generated by hypermail 2b29 : Sat Dec 23 2000 - 21:00:30 EST