From: Geert Uytterhoeven <geert+rene...@glider.be>
Date: Wed, 25 Jan 2017 11:39:47 +0100
> I started seeing crashes during s2ram and poweroff on all my ARM boards,
> like:
>
> Unable to handle kernel NULL pointer dereference at virtual address
> 00000000
> ...
> [<c04116d4>] (__list_del_entry_valid) from [<c05e8948>]
> (led_trigger_unregister+0x34/0xcc)
> [<c05e8948>] (led_trigger_unregister) from [<c05336c4>]
> (phy_led_triggers_unregister+0x28/0x34)
> [<c05336c4>] (phy_led_triggers_unregister) from [<c0531d44>]
> (phy_detach+0x30/0x74)
> [<c0531d44>] (phy_detach) from [<c0538bdc>] (sh_eth_close+0x64/0x9c)
> [<c0538bdc>] (sh_eth_close) from [<c04d4ce0>] (dpm_run_callback+0x48/0xc8)
>
> or:
>
> list_del corruption. prev->next should be dede6540, but was 2e323931
> ------------[ cut here ]------------
> kernel BUG at lib/list_debug.c:52!
> ...
> [<c02f6d70>] (__list_del_entry_valid) from [<c0425168>]
> (led_trigger_unregister+0x34/0xcc)
> [<c0425168>] (led_trigger_unregister) from [<c03a05a0>]
> (phy_led_triggers_unregister+0x28/0x34)
> [<c03a05a0>] (phy_led_triggers_unregister) from [<c039ec04>]
> (phy_detach+0x30/0x74)
> [<c039ec04>] (phy_detach) from [<c03a4fc0>] (sh_eth_close+0x6c/0xa4)
> [<c03a4fc0>] (sh_eth_close) from [<c0483234>] (__dev_close_many+0xac/0xd0)
>
> As the only clue was a kernel message like
>
> sh-eth ee700000.ethernet eth0: No phy led trigger registered for
> speed(100)
>
> I had to bisected this, leading to commit 4567d686f5c6d955 ("phy:
> increase size of MII_BUS_ID_SIZE and bus_id"). Reverting that commit
> fixed the issue.
>
> More investigation revealed the crashes are due to the combination of
> two things:
> - Truncated LED trigger names, leading to duplicate names, and
> registration failures,
> - Bad error handling in case of registration failures.
>
> Both are fixed by this patch series.
Thanks for tracking this down and fixing it.
Series applied, thanks.
