diff options
| author |   Robin Holt <holt@sgi.com> | 2009-12-15 16:47:57 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-16 07:20:14 -0800 |
| commit | 15b87d67ff3dc042bee42f991858d6b121b3b3ca (patch) | |
| tree | 48e72a7ce8b4113b3dfcdcd31ca9bdce38ee3cd9 /drivers/misc | |
| parent | x86: uv: update XPC to handle updated BIOS interface (diff) | |
| download | linux-dev-15b87d67ff3dc042bee42f991858d6b121b3b3ca.tar.xz linux-dev-15b87d67ff3dc042bee42f991858d6b121b3b3ca.zip | |
x86: uv: xpc NULL deref when mesq becomes empty
Under heavy load conditions, our set of xpc messages may become exhausted.
The code handles this correctly with the exception of the management code
which hits a NULL pointer dereference.
Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/misc')
| -rw-r--r-- | drivers/misc/sgi-xp/xpc_uv.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c index bbf0e2ee6fd9..19bd7b0ede91 100644 --- a/drivers/misc/sgi-xp/xpc_uv.c +++ b/drivers/misc/sgi-xp/xpc_uv.c @@ -949,11 +949,13 @@ xpc_get_fifo_entry_uv(struct xpc_fifo_head_uv *head) head->first = first->next; if (head->first == NULL) head->last = NULL; + + head->n_entries--; + BUG_ON(head->n_entries < 0); + + first->next = NULL; } - head->n_entries--; - BUG_ON(head->n_entries < 0); spin_unlock_irqrestore(&head->lock, irq_flags); - first->next = NULL; return first; } |