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Bluetooth: Fix hci_suspend_sync crash
[ Upstream commit 573ebae162
]
If hci_unregister_dev() frees the hci_dev object but hci_suspend_notifier
may still be accessing it, it can cause the program to crash.
Here's the call trace:
<4>[102152.653246] Call Trace:
<4>[102152.653254] hci_suspend_sync+0x109/0x301 [bluetooth]
<4>[102152.653259] hci_suspend_dev+0x78/0xcd [bluetooth]
<4>[102152.653263] hci_suspend_notifier+0x42/0x7a [bluetooth]
<4>[102152.653268] notifier_call_chain+0x43/0x6b
<4>[102152.653271] __blocking_notifier_call_chain+0x48/0x69
<4>[102152.653273] __pm_notifier_call_chain+0x22/0x39
<4>[102152.653276] pm_suspend+0x287/0x57c
<4>[102152.653278] state_store+0xae/0xe5
<4>[102152.653281] kernfs_fop_write+0x109/0x173
<4>[102152.653284] __vfs_write+0x16f/0x1a2
<4>[102152.653287] ? selinux_file_permission+0xca/0x16f
<4>[102152.653289] ? security_file_permission+0x36/0x109
<4>[102152.653291] vfs_write+0x114/0x21d
<4>[102152.653293] __x64_sys_write+0x7b/0xdb
<4>[102152.653296] do_syscall_64+0x59/0x194
<4>[102152.653299] entry_SYSCALL_64_after_hwframe+0x5c/0xc1
This patch holds the reference count of the hci_dev object while
processing it in hci_suspend_notifier to avoid potential crash
caused by the race condition.
Signed-off-by: Ying Hsu <yinghsu@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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1 changed files with 4 additions and 0 deletions
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@ -2436,6 +2436,9 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
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if (hci_dev_test_flag(hdev, HCI_USER_CHANNEL))
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return NOTIFY_DONE;
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/* To avoid a potential race with hci_unregister_dev. */
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hci_dev_hold(hdev);
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if (action == PM_SUSPEND_PREPARE)
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ret = hci_suspend_dev(hdev);
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else if (action == PM_POST_SUSPEND)
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@ -2445,6 +2448,7 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
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bt_dev_err(hdev, "Suspend notifier action (%lu) failed: %d",
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action, ret);
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hci_dev_put(hdev);
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return NOTIFY_DONE;
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}
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