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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.1 103/451] af_unix: Annotate data-race of gc_in_progress in wait_for_unix_gc().
Date: Sun, 24 Mar 2024 19:06:19 -0400
Message-ID: <20240324231207.1351418-104-sashal@kernel.org>
In-Reply-To: <20240324231207.1351418-1-sashal@kernel.org>
References: <20240324231207.1351418-1-sashal@kernel.org>
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From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit 31e03207119a535d0b0e3b3a7f91983aeb2cb14d ]

gc_in_progress is changed under spin_lock(&unix_gc_lock),
but wait_for_unix_gc() reads it locklessly.

Let's use READ_ONCE().

Fixes: 5f23b734963e ("net: Fix soft lockups/OOM issues w/ unix garbage collector")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240123170856.41348-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/unix/garbage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index ab2c83d58b62a..9bfffe2a7f020 100644
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -198,7 +198,7 @@ void wait_for_unix_gc(void)
 	if (READ_ONCE(unix_tot_inflight) > UNIX_INFLIGHT_TRIGGER_GC &&
 	    !READ_ONCE(gc_in_progress))
 		unix_gc();
-	wait_event(unix_gc_wait, gc_in_progress == false);
+	wait_event(unix_gc_wait, !READ_ONCE(gc_in_progress));
 }
 
 /* The external entry point: unix_gc() */
-- 
2.43.0