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From: Hillf Danton <hdanton@sina.com>
To: syzbot <syzbot+27209997e4015fb4702e@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in __hci_req_sync
Date: Sat, 13 Apr 2024 16:55:42 +0800
Message-Id: <20240413085542.1836-1-hdanton@sina.com>
In-Reply-To: <0000000000009e80a40615f5c189@google.com>
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On Sat, 13 Apr 2024 00:58:39 -0700
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    8f2c057754b2 Merge tag 'arm64-fixes' of git://git.kernel.o..
> git tree:       upstream
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=171da243180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git  8f2c057754b2

--- x/net/bluetooth/hci_request.c
+++ y/net/bluetooth/hci_request.c
@@ -102,6 +102,7 @@ void hci_req_sync_complete(struct hci_de
 {
 	bt_dev_dbg(hdev, "result 0x%2.2x", result);
 
+	hci_req_sync_lock(hdev);
 	if (hdev->req_status == HCI_REQ_PEND) {
 		hdev->req_result = result;
 		hdev->req_status = HCI_REQ_DONE;
@@ -111,6 +112,7 @@ void hci_req_sync_complete(struct hci_de
 		}
 		wake_up_interruptible(&hdev->req_wait_q);
 	}
+	hci_req_sync_unlock(hdev);
 }
 
 /* Execute request and wait for completion. */
--