linux-kernel - [PATCH] watchdog: Fix lockdep warning

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Date:   Fri, 11 Aug 2023 19:11:46 +0200
From:   Helge Deller <deller@....de>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, Petr Mladek <pmladek@...e.com>
Cc:     linux-parisc@...r.kernel.org
Subject: [PATCH] watchdog: Fix lockdep warning

Fully initialize detector_work work struct to avoid this kernel warning
when lockdep is enabled:

 =====================================
 WARNING: bad unlock balance detected!
 6.5.0-rc5+ #687 Not tainted
 -------------------------------------
 swapper/0/1 is trying to release lock (detector_work) at:
 [<000000004037e554>] __flush_work+0x60/0x658
 but there are no more locks to release!

 other info that might help us debug this:
 no locks held by swapper/0/1.

 stack backtrace:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.5.0-rc5+ #687
 Hardware name: 9000/785/C3700
 Backtrace:
  [<0000000041455d5c>] print_unlock_imbalance_bug.part.0+0x20c/0x230
  [<000000004040d5e8>] lock_release+0x2e8/0x3f8
  [<000000004037e5cc>] __flush_work+0xd8/0x658
  [<000000004037eb7c>] flush_work+0x30/0x60
  [<000000004011f140>] lockup_detector_check+0x54/0x128
  [<0000000040306430>] do_one_initcall+0x9c/0x408
  [<0000000040102d44>] kernel_init_freeable+0x688/0x7f0
  [<000000004146df68>] kernel_init+0x64/0x3a8
  [<0000000040302020>] ret_from_kernel_thread+0x20/0x28

Signed-off-by: Helge Deller <deller@....de>

---

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index be38276a365f..eab0dfcfa3f9 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -1022,5 +1022,6 @@ void __init lockup_detector_init(void)
 	else
 		allow_lockup_detector_init_retry = true;

+	INIT_WORK(&detector_work, lockup_detector_delay_init);
 	lockup_detector_setup();
 }