From d8aa5dd97944a72d4a9e3cc79bb80fcac7d6e829 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 20 Aug 2026 09:49:27 +0200 Subject: futex: Fix might_sleep() warning in futex_pivot_pending() A younger me put a WARN in might_sleep() to warn about nested sleep loops. This younger me also build a wait-loop variant that can deal with it. This wait-loop variant doesn't have all the fancy wrappers, since it isn't used much. It also lacks wait-bit support. Add the wait-bit support and use it to fix the nested wait issue. Fixes: 8e7ff730dd96 ("futex: Fix race in futex_pivot_pending() during private hash resize") Reported-by: syzbot+350a93852ac854927f45@syzkaller.appspotmail.com Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Link: https://patch.msgid.link/20260820074927.GH1246887@noisy.programming.kicks-ass.net Closes: https://syzkaller.appspot.com/bug?extid=350a93852ac854927f45 --- include/linux/wait_bit.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/wait_bit.h') diff --git a/include/linux/wait_bit.h b/include/linux/wait_bit.h index ace7379d627d..553d7b23e3ad 100644 --- a/include/linux/wait_bit.h +++ b/include/linux/wait_bit.h @@ -32,6 +32,7 @@ int out_of_line_wait_on_bit_timeout(unsigned long *word, int, wait_bit_action_f int out_of_line_wait_on_bit_lock(unsigned long *word, int, wait_bit_action_f *action, unsigned int mode); struct wait_queue_head *bit_waitqueue(unsigned long *word, int bit); extern void __init wait_bit_init(void); +extern struct wait_bit_key *__var_wake_key(struct wait_queue_entry *wq_entry, void *arg); int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync, void *key); -- cgit v1.2.3