| Message ID | 1485272470-3497-2-git-send-email-geert+renesas@glider.be |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
On 01/24/2017 07:41 AM, Geert Uytterhoeven wrote: > 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: 2e0bc452f4721520 ("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>
diff --git a/drivers/net/phy/phy_led_triggers.c b/drivers/net/phy/phy_led_triggers.c index fa62bdf2f52694de..3f619e7371e97d8a 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 @@ int phy_led_triggers_register(struct phy_device *phy) 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);
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: 2e0bc452f4721520 ("net: phy: leds: add support for led triggers on phy link state change") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- Alternatively, phy_attach_direct() could consider phy_led_triggers_register() failures as fatal, so phy_led_trigger_change_speed() and phy_led_triggers_unregister() are never called afterwards. Exposed by commit 4567d686f5c6d955 ("phy: increase size of MII_BUS_ID_SIZE and bus_id"), which caused duplicate trigger names. --- drivers/net/phy/phy_led_triggers.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)