From 4c62764d0fc21a34ffc44eec1210038c3a2e4473 Mon Sep 17 00:00:00 2001 From: Siva Rebbagondla Date: Mon, 27 Aug 2018 17:05:15 +0530 Subject: [PATCH] rsi: improve kernel thread handling to fix kernel panic While running regressions, observed below kernel panic when sdio disconnect called. This is because of, kthread_stop() is taking care of wait_for_completion() by default. When wait_for_completion triggered in kthread_stop and as it was done already, giving kernel panic. Hence, removing redundant wait_for_completion() from rsi_kill_thread(). ... skipping ... BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] exit_creds+0x1f/0x50 PGD 0 Oops: 0002 [#1] SMP CPU: 0 PID: 6502 Comm: rmmod Tainted: G OE 4.15.9-Generic #154-Ubuntu Hardware name: Dell Inc. Edge Gateway 3003/ , BIOS 01.00.00 04/17/2017 Stack: ffff88007392e600 ffff880075847dc0 ffffffff8108160a 0000000000000000 ffff88007392e600 ffff880075847de8 ffffffff810a484b ffff880076127000 ffff88003cd3a800 ffff880074f12a00 ffff880075847e28 ffffffffc09bed15 Call Trace: [] __put_task_struct+0x5a/0x140 [] kthread_stop+0x10b/0x110 [] rsi_disconnect+0x2f5/0x300 [ven_rsi_sdio] [] ? __pm_runtime_resume+0x5b/0x80 [] sdio_bus_remove+0x38/0x100 [] __device_release_driver+0xa4/0x150 [] driver_detach+0xb5/0xc0 [] bus_remove_driver+0x55/0xd0 [] driver_unregister+0x2c/0x50 [] sdio_unregister_driver+0x1a/0x20 [] rsi_module_exit+0x15/0x30 [ven_rsi_sdio] [] SyS_delete_module+0x1b8/0x210 [] entry_SYSCALL_64_fastpath+0x1c/0xbb Signed-off-by: Siva Rebbagondla Signed-off-by: Kalle Valo --- drivers/net/wireless/rsi/rsi_common.h | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/net/wireless/rsi/rsi_common.h b/drivers/net/wireless/rsi/rsi_common.h index d9ff3b8be86e..60f1f286b030 100644 --- a/drivers/net/wireless/rsi/rsi_common.h +++ b/drivers/net/wireless/rsi/rsi_common.h @@ -75,7 +75,6 @@ static inline int rsi_kill_thread(struct rsi_thread *handle) atomic_inc(&handle->thread_done); rsi_set_event(&handle->event); - wait_for_completion(&handle->completion); return kthread_stop(handle->task); } -- 2.11.0