Messages in this thread | | | Subject | Re: Deadlock in n_hdlc_buf_put | From | Jiri Slaby <> | Date | Thu, 26 Nov 2015 19:17:46 +0100 |
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On 11/26/2015, 01:37 PM, Dmitry Vyukov wrote: > [ 341.376188] ============================================= > [ 341.376607] [ INFO: possible recursive locking detected ] > [ 341.376607] 4.4.0-rc1+ #117 Not tainted > [ 341.376607] --------------------------------------------- > [ 341.376607] syzkaller_execu/14066 is trying to acquire lock: > [ 341.376607] (&(&list->spinlock)->rlock){......}, at: > [<ffffffff82a9f548>] n_hdlc_buf_put+0x28/0x170 > [ 341.376607] > [ 341.376607] but task is already holding lock: > [ 341.376607] (&(&list->spinlock)->rlock){......}, at: > [<ffffffff82aa1368>] n_hdlc_tty_ioctl+0x2b8/0x3f0 > [ 341.376607] > [ 341.376607] other info that might help us debug this: > [ 341.376607] Possible unsafe locking scenario: > [ 341.376607] > [ 341.376607] CPU0 > [ 341.376607] ---- > [ 341.376607] lock(&(&list->spinlock)->rlock); > [ 341.376607] lock(&(&list->spinlock)->rlock);
Hi,
this is a lockdep false positive. The first one is tx_buf_list.spinlock, the latter tx_free_buf_list.spinlock, both in flush_tx_queue. So we need a lockdep annotation here.
thanks, -- js suse labs
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