Merge branch 'exit-cleanups-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull exit cleanups from Eric Biederman:
 "While looking at some issues related to the exit path in the kernel I
  found several instances where the code is not using the existing
  abstractions properly.

  This set of changes introduces force_fatal_sig a way of sending a
  signal and not allowing it to be caught, and corrects the misuse of
  the existing abstractions that I found.

  A lot of the misuse of the existing abstractions are silly things such
  as doing something after calling a no return function, rolling BUG by
  hand, doing more work than necessary to terminate a kernel thread, or
  calling do_exit(SIGKILL) instead of calling force_sig(SIGKILL).

  In the review a deficiency in force_fatal_sig and force_sig_seccomp
  where ptrace or sigaction could prevent the delivery of the signal was
  found. I have added a change that adds SA_IMMUTABLE to change that
  makes it impossible to interrupt the delivery of those signals, and
  allows backporting to fix force_sig_seccomp

  And Arnd found an issue where a function passed to kthread_run had the
  wrong prototype, and after my cleanup was failing to build."

* 'exit-cleanups-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (23 commits)
  soc: ti: fix wkup_m3_rproc_boot_thread return type
  signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed
  signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV)
  exit/r8188eu: Replace the macro thread_exit with a simple return 0
  exit/rtl8712: Replace the macro thread_exit with a simple return 0
  exit/rtl8723bs: Replace the macro thread_exit with a simple return 0
  signal/x86: In emulate_vsyscall force a signal instead of calling do_exit
  signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig
  signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails
  exit/syscall_user_dispatch: Send ordinary signals on failure
  signal: Implement force_fatal_sig
  exit/kthread: Have kernel threads return instead of calling do_exit
  signal/s390: Use force_sigsegv in default_trap_handler
  signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.
  signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON
  signal/sparc: In setup_tsb_params convert open coded BUG into BUG
  signal/powerpc: On swapcontext failure force SIGSEGV
  signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL)
  signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT
  signal/sparc32: Remove unreachable do_exit in do_sparc_fault
  ...

10 files changed, 11 insertions, 15 deletions

diff --git a/drivers/firmware/stratix10-svc.c b/drivers/firmware/stratix10-svc.c
index 2a7687911c09..29c0a616b317 100644
--- a/drivers/firmware/stratix10-svc.c
+++ b/drivers/firmware/stratix10-svc.c
@@ -520,7 +520,7 @@ static int svc_normal_to_secure_thread(void *data)
  * physical address of memory block reserved by secure monitor software at
  * secure world.
  *
- * svc_normal_to_secure_shm_thread() calls do_exit() directly since it is a
+ * svc_normal_to_secure_shm_thread() terminates directly since it is a
  * standlone thread for which no one will call kthread_stop() or return when
  * 'kthread_should_stop()' is true.
  */
@@ -544,7 +544,7 @@ static int svc_normal_to_secure_shm_thread(void *data)
 	}
 
 	complete(&sh_mem->sync_complete);
-	do_exit(0);
+	return 0;
 }
 
 /**
diff --git a/drivers/soc/ti/wkup_m3_ipc.c b/drivers/soc/ti/wkup_m3_ipc.c
index 09abd17065ba..72386bd393fe 100644
--- a/drivers/soc/ti/wkup_m3_ipc.c
+++ b/drivers/soc/ti/wkup_m3_ipc.c
@@ -413,8 +413,9 @@ void wkup_m3_ipc_put(struct wkup_m3_ipc *m3_ipc)
 }
 EXPORT_SYMBOL_GPL(wkup_m3_ipc_put);
 
-static void wkup_m3_rproc_boot_thread(struct wkup_m3_ipc *m3_ipc)
+static int wkup_m3_rproc_boot_thread(void *arg)
 {
+	struct wkup_m3_ipc *m3_ipc = arg;
 	struct device *dev = m3_ipc->dev;
 	int ret;
 
@@ -426,7 +427,7 @@ static void wkup_m3_rproc_boot_thread(struct wkup_m3_ipc *m3_ipc)
 	else
 		m3_ipc_state = m3_ipc;
 
-	do_exit(0);
+	return 0;
 }
 
 static int wkup_m3_ipc_probe(struct platform_device *pdev)
@@ -500,7 +501,7 @@ static int wkup_m3_ipc_probe(struct platform_device *pdev)
 	 * can boot the wkup_m3 as soon as it's ready without holding
 	 * up kernel boot
 	 */
-	task = kthread_run((void *)wkup_m3_rproc_boot_thread, m3_ipc,
+	task = kthread_run(wkup_m3_rproc_boot_thread, m3_ipc,
 			   "wkup_m3_rproc_loader");
 
 	if (IS_ERR(task)) {
diff --git a/drivers/staging/r8188eu/core/rtw_cmd.c b/drivers/staging/r8188eu/core/rtw_cmd.c
index 5d5f25364b2f..48869a7056fd 100644
--- a/drivers/staging/r8188eu/core/rtw_cmd.c
+++ b/drivers/staging/r8188eu/core/rtw_cmd.c
@@ -323,7 +323,7 @@ post_process:
 
 	complete(&pcmdpriv->stop_cmd_thread);
 
-	thread_exit();
+	return 0;
 }
 
 /*
diff --git a/drivers/staging/r8188eu/include/osdep_service.h b/drivers/staging/r8188eu/include/osdep_service.h
index efab3a97eb46..f6f5e4581212 100644
--- a/drivers/staging/r8188eu/include/osdep_service.h
+++ b/drivers/staging/r8188eu/include/osdep_service.h
@@ -49,8 +49,6 @@ struct	__queue	{
 	spinlock_t lock;
 };
 
-#define thread_exit() complete_and_exit(NULL, 0)
-
 static inline struct list_head *get_list_head(struct __queue *queue)
 {
 	return (&(queue->queue));
diff --git a/drivers/staging/rtl8712/osdep_service.h b/drivers/staging/rtl8712/osdep_service.h
index d33ddffb7ad9..0d9bb42cbc58 100644
--- a/drivers/staging/rtl8712/osdep_service.h
+++ b/drivers/staging/rtl8712/osdep_service.h
@@ -37,7 +37,6 @@ struct	__queue	{
 
 #define _pkt struct sk_buff
 #define _buffer unsigned char
-#define thread_exit() complete_and_exit(NULL, 0)
 
 #define _init_queue(pqueue)				\
 	do {						\
diff --git a/drivers/staging/rtl8712/rtl8712_cmd.c b/drivers/staging/rtl8712/rtl8712_cmd.c
index e9294e1ed06e..2326aae6709e 100644
--- a/drivers/staging/rtl8712/rtl8712_cmd.c
+++ b/drivers/staging/rtl8712/rtl8712_cmd.c
@@ -393,7 +393,7 @@ _next:
 		r8712_free_cmd_obj(pcmd);
 	} while (1);
 	complete(&pcmdpriv->terminate_cmdthread_comp);
-	thread_exit();
+	return 0;
 }
 
 void r8712_event_handle(struct _adapter *padapter, __le32 *peventbuf)
diff --git a/drivers/staging/rtl8723bs/core/rtw_cmd.c b/drivers/staging/rtl8723bs/core/rtw_cmd.c
index 639459d52261..bd24d913b464 100644
--- a/drivers/staging/rtl8723bs/core/rtw_cmd.c
+++ b/drivers/staging/rtl8723bs/core/rtw_cmd.c
@@ -518,7 +518,7 @@ post_process:
 	complete(&pcmdpriv->terminate_cmdthread_comp);
 	atomic_set(&pcmdpriv->cmdthd_running, false);
 
-	thread_exit();
+	return 0;
 }
 
 /*
diff --git a/drivers/staging/rtl8723bs/core/rtw_xmit.c b/drivers/staging/rtl8723bs/core/rtw_xmit.c
index 46054d6a1fb5..13b8bd5ffabc 100644
--- a/drivers/staging/rtl8723bs/core/rtw_xmit.c
+++ b/drivers/staging/rtl8723bs/core/rtw_xmit.c
@@ -2500,7 +2500,7 @@ int rtw_xmit_thread(void *context)
 
 	complete(&padapter->xmitpriv.terminate_xmitthread_comp);
 
-	thread_exit();
+	return 0;
 }
 
 void rtw_sctx_init(struct submit_ctx *sctx, int timeout_ms)
diff --git a/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c b/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c
index 5f5c4719b586..7fe3df863fe1 100644
--- a/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c
+++ b/drivers/staging/rtl8723bs/hal/rtl8723bs_xmit.c
@@ -435,7 +435,7 @@ int rtl8723bs_xmit_thread(void *context)
 
 	complete(&pxmitpriv->SdioXmitTerminate);
 
-	thread_exit();
+	return 0;
 }
 
 s32 rtl8723bs_mgnt_xmit(
diff --git a/drivers/staging/rtl8723bs/include/osdep_service_linux.h b/drivers/staging/rtl8723bs/include/osdep_service_linux.h
index 3492ec1efd1e..188ed7e26550 100644
--- a/drivers/staging/rtl8723bs/include/osdep_service_linux.h
+++ b/drivers/staging/rtl8723bs/include/osdep_service_linux.h
@@ -45,8 +45,6 @@
 		spinlock_t	lock;
 	};
 
-	#define thread_exit() complete_and_exit(NULL, 0)
-
 static inline struct list_head *get_next(struct list_head	*list)
 {
 	return list->next;