Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") removed various __user annotations from function signatures as part of its refactoring. It also removed the __user annotation for proc_dohung_task_timeout_secs() at its declaration in ./sched/sysctl.h, but not at its definition in ./kernel/hung_task.c. Hence, sparse complains: kernel/hung_task.c:271:5: error: \ symbol 'proc_dohung_task_timeout_secs' redeclared with different type \ (incompatible argument 3 (different address spaces)) Adjust the annotation at the definition fitting to that refactoring to make sparse happy again, which also resolves this warning from sparse: kernel/hung_task.c:277:52: warning: incorrect type in argument 3 \ (different address spaces) kernel/hung_task.c:277:52: expected void * kernel/hung_task.c:277:52: got void [noderef] __user *buffer No functional change. No change in object code. Signed-off-by: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx> --- applies cleanly on current master and next-20201028 Christoph, can I get quick ack from you on a fix to your refactoring? Andrew, please pick this minor non-urgent clean-up patch. kernel/hung_task.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index a672db830a94..bb2e3e15c84c 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -269,8 +269,7 @@ static long hung_timeout_jiffies(unsigned long last_checked, * Process updating of timeout sysctl */ int proc_dohung_task_timeout_secs(struct ctl_table *table, int write, - void __user *buffer, - size_t *lenp, loff_t *ppos) + void *buffer, size_t *lenp, loff_t *ppos) { int ret; -- 2.17.1