[PATCH 5.15 069/317] af_unix: Annotate data-race of gc_in_progress in wait_for_unix_gc().

Sasha Levin
2024-03-24T23:36:10Z

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