Hi,
On 4/6/22 08:34, Guenter Roeck wrote:
In Chrome OS, a large number of crashes is observed due to corrupted timer
lists. Steven Rostedt pointed out that this usually happens when a timer
is freed while still active, and that the problem is often triggered
by code calling del_timer() instead of del_timer_sync() just before
freeing.
Steven also identified the iwlwifi driver as one of the possible culprits
since it does exactly that.
Reported-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Shahar S Matityahu <shahar.s.matityahu@xxxxxxxxx>
Cc: Johannes Berg <johannes.berg@xxxxxxxxx>
Fixes: 60e8abd9d3e91 ("iwlwifi: dbg_ini: add periodic trigger new API support")
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
RFC:
Maybe there was a reason to use del_timer() instead of del_timer_sync().
Also, I am not sure if the change is sufficient since I don't see any
obvious locking that would prevent timers from being added and then
modified in iwl_dbg_tlv_set_periodic_trigs() while being removed in
iwl_dbg_tlv_del_timers().
I prepared a new version of this patch, introducing a mutex to protect changes
to periodic_trig_list. I'd like to get some feedback before sending it out,
though, so I'll wait until next week before sending it.
If you have any feedback/thoughts/comments, please let me know.
Thanks,
Guenter
drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c b/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
index 866a33f49915..3237d4b528b5 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-dbg-tlv.c
@@ -371,7 +371,7 @@ void iwl_dbg_tlv_del_timers(struct iwl_trans *trans)
struct iwl_dbg_tlv_timer_node *node, *tmp;
list_for_each_entry_safe(node, tmp, timer_list, list) {
- del_timer(&node->timer);
+ del_timer_sync(&node->timer);
list_del(&node->list);
kfree(node);
}
