From 8a87fca8dd5879eb05a0903cb7ea4fd2a3876ae0 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 25 Jan 2017 11:39:48 +0100 Subject: [PATCH] net: phy: leds: Clear phy_num_led_triggers on failure to avoid crash 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 ... [] (__list_del_entry_valid) from [] (led_trigger_unregister+0x34/0xcc) [] (led_trigger_unregister) from [] (phy_led_triggers_unregister+0x28/0x34) [] (phy_led_triggers_unregister) from [] (phy_detach+0x30/0x74) [] (phy_detach) from [] (sh_eth_close+0x64/0x9c) [] (sh_eth_close) from [] (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! ... [] (__list_del_entry_valid) from [] (led_trigger_unregister+0x34/0xcc) [] (led_trigger_unregister) from [] (phy_led_triggers_unregister+0x28/0x34) [] (phy_led_triggers_unregister) from [] (phy_detach+0x30/0x74) [] (phy_detach) from [] (sh_eth_close+0x6c/0xa4) [] (sh_eth_close) from [] (__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: 2e0bc452f4721520 ("net: phy: leds: add support for led triggers on phy link state change") Signed-off-by: Geert Uytterhoeven Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- drivers/net/phy/phy_led_triggers.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/phy/phy_led_triggers.c b/drivers/net/phy/phy_led_triggers.c index fa62bdf2f526..3f619e7371e9 100644 --- a/drivers/net/phy/phy_led_triggers.c +++ b/drivers/net/phy/phy_led_triggers.c @@ -102,8 +102,10 @@ int phy_led_triggers_register(struct phy_device *phy) sizeof(struct phy_led_trigger) * phy->phy_num_led_triggers, GFP_KERNEL); - if (!phy->phy_led_triggers) - return -ENOMEM; + if (!phy->phy_led_triggers) { + err = -ENOMEM; + goto out_clear; + } for (i = 0; i < phy->phy_num_led_triggers; i++) { err = phy_led_trigger_register(phy, &phy->phy_led_triggers[i], @@ -120,6 +122,8 @@ out_unreg: while (i--) phy_led_trigger_unregister(&phy->phy_led_triggers[i]); devm_kfree(&phy->mdio.dev, phy->phy_led_triggers); +out_clear: + phy->phy_num_led_triggers = 0; return err; } EXPORT_SYMBOL_GPL(phy_led_triggers_register); -- 2.34.1