5.10-stable review patch. If anyone has any objections, please let me know.
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From: Eric W. Biederman ebiederm@xmission.com
[ Upstream commit bbda86e988d4c124e4cfa816291cbd583ae8bfb1 ]
The way the per task_struct exit_code is used by kernel threads is not quite compatible how it is used by userspace applications. The low byte of the userspace exit_code value encodes the exit signal. While kthreads just use the value as an int holding ordinary kernel function exit status like -EPERM.
Add kthread_exit to clearly separate the two kinds of uses.
Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Stable-dep-of: ca3574bd653a ("exit: Rename module_put_and_exit to module_put_and_kthread_exit") Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/kthread.h | 1 + kernel/kthread.c | 23 +++++++++++++++++++---- tools/objtool/check.c | 1 + 3 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/include/linux/kthread.h b/include/linux/kthread.h index 2484ed97e72f5..9dae77a97a033 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -68,6 +68,7 @@ void *kthread_probe_data(struct task_struct *k); int kthread_park(struct task_struct *k); void kthread_unpark(struct task_struct *k); void kthread_parkme(void); +void kthread_exit(long result) __noreturn;
int kthreadd(void *unused); extern struct task_struct *kthreadd_task; diff --git a/kernel/kthread.c b/kernel/kthread.c index 508fe52782857..9d6cc9c15a55e 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -262,6 +262,21 @@ void kthread_parkme(void) } EXPORT_SYMBOL_GPL(kthread_parkme);
+/** + * kthread_exit - Cause the current kthread return @result to kthread_stop(). + * @result: The integer value to return to kthread_stop(). + * + * While kthread_exit can be called directly, it exists so that + * functions which do some additional work in non-modular code such as + * module_put_and_kthread_exit can be implemented. + * + * Does not return. + */ +void __noreturn kthread_exit(long result) +{ + do_exit(result); +} + static int kthread(void *_create) { /* Copy data: it's on kthread's stack */ @@ -279,13 +294,13 @@ static int kthread(void *_create) done = xchg(&create->done, NULL); if (!done) { kfree(create); - do_exit(-EINTR); + kthread_exit(-EINTR); }
if (!self) { create->result = ERR_PTR(-ENOMEM); complete(done); - do_exit(-ENOMEM); + kthread_exit(-ENOMEM); }
self->threadfn = threadfn; @@ -312,7 +327,7 @@ static int kthread(void *_create) __kthread_parkme(self); ret = threadfn(data); } - do_exit(ret); + kthread_exit(ret); }
/* called from do_fork() to get node information for about to be created task */ @@ -621,7 +636,7 @@ EXPORT_SYMBOL_GPL(kthread_park); * instead of calling wake_up_process(): the thread will exit without * calling threadfn(). * - * If threadfn() may call do_exit() itself, the caller must ensure + * If threadfn() may call kthread_exit() itself, the caller must ensure * task_struct can't go away. * * Returns the result of threadfn(), or %-EINTR if wake_up_process() diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 059b78d08f7af..6afa1f8ca1614 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -168,6 +168,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func, "panic", "do_exit", "do_task_dead", + "kthread_exit", "make_task_dead", "__module_put_and_exit", "complete_and_exit",