On 10.10.2023 09:35:19, Marc Kleine-Budde wrote:
> The dm9000 takes the db->lock spin lock in dm9000_timeout() and calls
> into dm9000_init_dm9000(). For the DM9000B the PHY is reset with
> dm9000_phy_write(). That function again takes the db->lock spin lock,
> which results in a deadlock. For reference the backtrace:
>
> | [<c0425050>] (rt_spin_lock_slowlock_locked) from [<c0425100>] (rt_spin_lock_slowlock+0x60/0xc4)
> | [<c0425100>] (rt_spin_lock_slowlock) from [<c02e1174>] (dm9000_phy_write+0x2c/0x1a4)
> | [<c02e1174>] (dm9000_phy_write) from [<c02e16b0>] (dm9000_init_dm9000+0x288/0x2a4)
> | [<c02e16b0>] (dm9000_init_dm9000) from [<c02e1724>] (dm9000_timeout+0x58/0xd4)
> | [<c02e1724>] (dm9000_timeout) from [<c036f298>] (dev_watchdog+0x258/0x2a8)
> | [<c036f298>] (dev_watchdog) from [<c0068168>] (call_timer_fn+0x20/0x88)
> | [<c0068168>] (call_timer_fn) from [<c00687c8>] (expire_timers+0xf0/0x194)
> | [<c00687c8>] (expire_timers) from [<c0068920>] (run_timer_softirq+0xb4/0x25c)
> | [<c0068920>] (run_timer_softirq) from [<c0021a30>] (do_current_softirqs+0x16c/0x228)
> | [<c0021a30>] (do_current_softirqs) from [<c0021b14>] (run_ksoftirqd+0x28/0x4c)
> | [<c0021b14>] (run_ksoftirqd) from [<c0040488>] (smpboot_thread_fn+0x278/0x290)
> | [<c0040488>] (smpboot_thread_fn) from [<c003c28c>] (kthread+0x124/0x164)
> | [<c003c28c>] (kthread) from [<c00090f0>] (ret_from_fork+0x14/0x24)
>
> To workaround similar problem (take mutex inside spin lock ) , a
> "in_timeout" variable was added in 582379839bbd ("dm9000: avoid
> sleeping in dm9000_timeout callback"). Use this variable and not take
> the spin lock inside dm9000_phy_write() if in_timeout is true.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Fixes: a1365275e745 ("[PATCH] DM9000 network driver")
regards,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
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