mirror of
https://github.com/torvalds/linux.git
synced 2024-11-11 14:42:24 +00:00
b8cedb7093
When removing the pn533 device (i2c or USB), there is a logic error. The original code first cancels the worker (flush_delayed_work) and then destroys the workqueue (destroy_workqueue), leaving the timer the last one to be deleted (del_timer). This result in a possible race condition in a multi-core preempt-able kernel. That is, if the cleanup (pn53x_common_clean) is concurrently run with the timer handler (pn533_listen_mode_timer), the timer can queue the poll_work to the already destroyed workqueue, causing use-after-free. This patch reorder the cleanup: it uses the del_timer_sync to make sure the handler is finished before the routine will destroy the workqueue. Note that the timer cannot be activated by the worker again. static void pn533_wq_poll(struct work_struct *work) ... rc = pn533_send_poll_frame(dev); if (rc) return; if (cur_mod->len == 0 && dev->poll_mod_count > 1) mod_timer(&dev->listen_timer, ...); That is, the mod_timer can be called only when pn533_send_poll_frame() returns no error, which is impossible because the device is detaching and the lower driver should return ENODEV code. Signed-off-by: Lin Ma <linma@zju.edu.cn> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|---|---|---|
| .. | ||
| fdp | ||
| microread | ||
| nfcmrvl | ||
| nxp-nci | ||
| pn533 | ||
| pn544 | ||
| s3fwrn5 | ||
| st21nfca | ||
| st95hf | ||
| st-nci | ||
| Kconfig | ||
| Makefile | ||
| mei_phy.c | ||
| mei_phy.h | ||
| nfcsim.c | ||
| port100.c | ||
| trf7970a.c | ||
| virtual_ncidev.c | ||