From: Jiakai Xu Date: Sat, 23 May 2026 02:23:14 +0000 (+0000) Subject: PM: sleep: Use complete() in device_pm_sleep_init() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3855941f1e4069182c895d5093c5fa589f5b38bd;p=thirdparty%2Flinux.git PM: sleep: Use complete() in device_pm_sleep_init() Replace complete_all() with complete() in device_pm_sleep_init() to allow it to be called in atomic contexts without triggering a false-positive WARNING from lockdep_assert_RT_in_threaded_ctx() when CONFIG_PROVE_RAW_LOCK_NESTING is enabled. device_pm_sleep_init() may be called during device initialization while holding a raw_spinlock (e.g., from within device_initialize()), and complete_all() is unsafe in atomic contexts on PREEMPT_RT kernels. complete(), which is safe to call from any context, is sufficient here. complete_all() sets the completion count to UINT_MAX/2 (permanently signaled), while complete() increments it by 1. Since no threads can be waiting during device initialization, both are functionally equivalent. The completion is always reinitialized via reinit_completion() in dpm_clear_async_state() before each suspend/resume cycle. However, changing to complete() introduces a potential deadlock for devices with no PM support (dev->power.no_pm = true). Such devices are never added to the dpm_list and never go through dpm_clear_async_state(), so their completion is never reinitialized. A parent device waiting on a no_pm child across multiple suspend phases would consume the single-use token in the first phase and block forever in the second. Fix this by adding an early return in dpm_wait() when dev->power.no_pm is set, since no_pm devices do not participate in system suspend/resume. Fixes: 152e1d592071 ("PM: Prevent waiting forever on asynchronous resume after failing suspend") Signed-off-by: Jiakai Xu [ rjw: Subject adjustment ] Link: https://patch.msgid.link/20260523022314.2657232-1-xujiakai24@mails.ucas.ac.cn Signed-off-by: Rafael J. Wysocki --- diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index e1b550664babb..ed48c292f5757 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -115,7 +115,7 @@ void device_pm_sleep_init(struct device *dev) dev->power.is_noirq_suspended = false; dev->power.is_late_suspended = false; init_completion(&dev->power.completion); - complete_all(&dev->power.completion); + complete(&dev->power.completion); dev->power.wakeup = NULL; INIT_LIST_HEAD(&dev->power.entry); } @@ -252,6 +252,10 @@ static void dpm_wait(struct device *dev, bool async) if (!dev) return; + /* Devices with no PM support don't use the completion. */ + if (dev->power.no_pm) + return; + if (async || (pm_async_enabled && dev->power.async_suspend)) wait_for_completion(&dev->power.completion); }