On 3/1/23 14:42, Jakob Koschel wrote:
On 23/03/01 10:31AM, Guenter Roeck wrote:
On 3/1/23 09:17, Jakob Koschel wrote:
If potentially no valid element is found, 'p' would contain an invalid
pointer past the iterator loop. To ensure 'p' is valid under any
circumstances, the kfree() should be within the loop body.
Additionally, Linus proposed to avoid any use of the list iterator
variable after the loop, in the attempt to move the list iterator
variable declaration into the marcro to avoid any potential misuse after
macro
the loop [1].
Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@xxxxxxxxxxxxxx/ [1]
Signed-off-by: Jakob Koschel <jkl820.git@xxxxxxxxx>
---
drivers/watchdog/watchdog_pretimeout.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/watchdog/watchdog_pretimeout.c b/drivers/watchdog/watchdog_pretimeout.c
index 376a495ab80c..d8c78696eaf5 100644
--- a/drivers/watchdog/watchdog_pretimeout.c
+++ b/drivers/watchdog/watchdog_pretimeout.c
@@ -207,10 +207,10 @@ void watchdog_unregister_pretimeout(struct watchdog_device *wdd)
list_for_each_entry_safe(p, t, &pretimeout_list, entry) {
if (p->wdd == wdd) {
list_del(&p->entry);
- break;
+ spin_unlock_irq(&pretimeout_lock);
+ kfree(p);
+ return;
Please just make it
kfree(p);
break;
There is no need to drop the spinlock here and/or to return
directly.
Ok great, I'll fix that in v2. I wasn't sure if something breaks if 'p' is released if the spinlock is still hold.
Ah, interesting question. Looking into it, I don't think that is a problem.
Just to be sure, I wrote a little coccinelle script to find calls to kfree()
under spinlock_irq() and found several instances.
Guenter
