8a87fca8dd
phy_attach_direct() ignores errors returned by
phy_led_triggers_register(). I think that's OK, as LED triggers can be
considered a non-critical feature.
However, this causes problems later:
- phy_led_trigger_change_speed() will access the array
phy_device.phy_led_triggers, which has been freed in the error path
of phy_led_triggers_register(), which may lead to a crash.
- phy_led_triggers_unregister() will access the same array, leading to
crashes during s2ram or poweroff, 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)
To fix this, clear phy_device.phy_num_led_triggers in the error path of
phy_led_triggers_register() fails.
Note that the "No phy led trigger registered for speed" message will
still be printed on link speed changes, which is a good cue that
something went wrong with the LED triggers.
Fixes: 2e0bc452f4 ("net: phy: leds: add support for led triggers on phy link state change")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.