On 11/08/2017 11:11 AM, Andrew Banman wrote:
On 11/8/17 11:06 AM, Andrew Banman wrote:
If there are uninitialized SMIs in the smi_infos list, i.e. with no
handlers set, then disable_si_irq() in cleanup_smi_one() will hit a null
pointer dereference when the former attempts to start the check enables
transaction. Thus, we panic during module exit.
I think this points to a broader problem of holding uninitialized
smi_info
structs in smi_infos list. There are many places where handlers and
other struct
members are assumed. Maybe a better design would be to remove SMIs
from the list
if we have no intention of initializing them?
This begs the question: How did you produce this? From what I can tell,
there is no way you can get to this code if you don't have a working and
initialized smi_info structure, and that's not the only place this would
have to be fixed if it wasn't. So it's not what you assume, I don't think
it's an uninitialized smi_info structure on the list.
As usual with these sorts of things, please send tracebacks and reproduction
procedures.
If you are removing the module and this happens, there may be a race
conditions, but this is the wrong fix. More likely that the structure gets
cleaned up and this function is called afterwards.
-corey
Andrew
Avoid panicking when there are uninitialized SMIs by checking for a
handler
pointer before starting the check enables transaction.
Signed-off-by: Andrew Banman <aban...@hpe.com>
---
drivers/char/ipmi/ipmi_si_intf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/ipmi/ipmi_si_intf.c
b/drivers/char/ipmi/ipmi_si_intf.c
index cb5719e..6c0b1b3 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -442,7 +442,7 @@ static void start_check_enables(struct smi_info
*smi_info, bool start_timer)
if (start_timer)
start_new_msg(smi_info, msg, 2);
- else
+ else if (smi_info->handlers)
smi_info->handlers->start_transaction(smi_info->si_sm, msg, 2);
smi_info->si_state = SI_CHECKING_ENABLES;
}
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