linux-kernel - [PATCH] binder_alloc: Fix sleeping function called from invalid context

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Message-ID: <20240724155555.2405467-1-quic_mojha@quicinc.com>
Date: Wed, 24 Jul 2024 21:25:55 +0530
From: Mukesh Ojha <quic_mojha@...cinc.com>
To: <gregkh@...uxfoundation.org>, <arve@...roid.com>, <tkjos@...roid.com>,
        <maco@...roid.com>, <joel@...lfernandes.org>, <brauner@...nel.org>,
        <cmllamas@...gle.com>, <surenb@...gle.com>
CC: <linux-kernel@...r.kernel.org>, Mukesh Ojha <quic_mojha@...cinc.com>
Subject: [PATCH] binder_alloc: Fix sleeping function called from invalid context

36c55ce8703c ("binder_alloc: Replace kcalloc with kvcalloc to
mitigate OOM issues") introduce schedule while atomic issue.

[ 2689.152635][ T4275] BUG: sleeping function called from invalid context at mm/vmalloc.c:2847
[ 2689.161291][ T4275] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4275, name: kworker/1:140
[ 2689.170708][ T4275] preempt_count: 1, expected: 0
[ 2689.175572][ T4275] RCU nest depth: 0, expected: 0
[ 2689.180521][ T4275] INFO: lockdep is turned off.
[ 2689.180523][ T4275] Preemption disabled at:
[ 2689.180525][ T4275] [<ffffffe031f2a2dc>] binder_alloc_deferred_release+0x2c/0x388
..
..
[ 2689.213419][ T4275]  __might_resched+0x174/0x178
[ 2689.213423][ T4275]  __might_sleep+0x48/0x7c
[ 2689.213426][ T4275]  vfree+0x4c/0x15c
[ 2689.213430][ T4275]  kvfree+0x24/0x44
[ 2689.213433][ T4275]  binder_alloc_deferred_release+0x2c0/0x388
[ 2689.213436][ T4275]  binder_proc_dec_tmpref+0x15c/0x2a8
[ 2689.213440][ T4275]  binder_deferred_func+0xa8/0x8ec
[ 2689.213442][ T4275]  process_one_work+0x254/0x59c
[ 2689.213447][ T4275]  worker_thread+0x274/0x3ec
[ 2689.213450][ T4275]  kthread+0x110/0x134
[ 2689.213453][ T4275]  ret_from_fork+0x10/0x20

Fix it by moving the place of kvfree outside of spinlock context.

Fixes: 36c55ce8703c ("binder_alloc: Replace kcalloc with kvcalloc to mitigate OOM issues")
Signed-off-by: Mukesh Ojha <quic_mojha@...cinc.com>
---
 drivers/android/binder_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index b00961944ab1..b3acbc4174fb 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -939,9 +939,9 @@ void binder_alloc_deferred_release(struct binder_alloc *alloc)
 			__free_page(alloc->pages[i].page_ptr);
 			page_count++;
 		}
-		kvfree(alloc->pages);
 	}
 	spin_unlock(&alloc->lock);
+	kvfree(alloc->pages);
 	if (alloc->mm)
 		mmdrop(alloc->mm);
 
-- 
2.34.1