From: Adam Belay <ambx1@neo.rr.com>
It is not safe to use the skt_sem in pcmcia_validate_mem. This patch fixes a
real world bug, and without it many systems will fail to shutdown properly.
When pcmcia-cs calls DS_EJECT_CARD, it creates a CS_EVENT_EJECTION_REQUEST
event. The event is then eventually reported to the ds.c client. DS then
informs userspace of the ejection request and waits for userspace to reply
with whether the request was successful. pcmcia-cs, in turn, calls
DS_GET_FIRST_TUPLE while verifying the ejection request. Unfortunately, at
this point the skt_sem semaphore is already held by pcmcia_eject_card. This
results in the ds event code waiting forever for skt_sem to become available.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/pcmcia/rsrc_mgr.c | 4 ----
1 files changed, 4 deletions(-)
diff -puN drivers/pcmcia/rsrc_mgr.c~pcmcia-fix-eject-lockup drivers/pcmcia/rsrc_mgr.c
--- 25/drivers/pcmcia/rsrc_mgr.c~pcmcia-fix-eject-lockup 2004-08-24 22:07:04.283881592 -0700
+++ 25-akpm/drivers/pcmcia/rsrc_mgr.c 2004-08-24 22:07:04.288880832 -0700
@@ -514,12 +514,8 @@ static void validate_mem(struct pcmcia_s
void pcmcia_validate_mem(struct pcmcia_socket *s)
{
- down(&s->skt_sem);
-
if (probe_mem && s->state & SOCKET_PRESENT)
validate_mem(s);
-
- up(&s->skt_sem);
}
EXPORT_SYMBOL(pcmcia_validate_mem);
_