[PATCH net] net: octeon_mgmt: kill TX tasklet before freeing rings

[PATCH net] net: octeon_mgmt: kill TX tasklet before freeing rings

[Hongyan Xu]

The interrupt handler schedules tx_clean_tasklet, which dereferences the
private state and TX ring. free_irq() prevents new scheduling but does
not wait for a tasklet that was already queued.

Kill the tasklet after freeing the interrupt and before purging and
freeing the DMA rings.

Fixes: d6aa60a10b2f ("NET: Add Ethernet driver for Octeon MGMT devices.")
Signed-off-by: Hongyan Xu <getshell@seu.edu.cn>
---
 drivers/net/ethernet/cavium/octeon/octeon_mgmt.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
index c190fc6538d4..2cf3365b9636 100644
--- a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
+++ b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
@@ -1254,6 +1254,7 @@ static int octeon_mgmt_stop(struct net_device *netdev)
 	octeon_mgmt_reset_hw(p);
 
 	free_irq(p->irq, netdev);
+	tasklet_kill(&p->tx_clean_tasklet);
 
 	/* dma_unmap is a nop on Octeon, so just free everything.  */
 	skb_queue_purge(&p->tx_list);
-- 
2.50.1.windows.1

Re: [PATCH net] net: octeon_mgmt: kill TX tasklet before freeing rings

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - How the issue was discovered, e.g. hit in production, hit during
   development, syzbot report, manual code inspection, LLM or static
   analysis tool scan.

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
   the symptoms, like the stack trace or error messages.

 - What hardware the change was tested on. For driver fixes please
   mention the device (and if relevant firmware version) used for
   testing, or say that the change was not tested on real hardware.

Please do not repost the series just to address the above. Instead,
reply to this email with the missing information, so that reviewers
can take it into account. If the series needs another revision for
other reasons, please include the information in the commit messages
then.

The evaluation is done by an LLM so it may be wrong, if you think
that is the case please reply and explain.