Hi Jiri,
thanks for looking into this.
On Thu, Nov 1, 2012 at 11:32 AM, Jiri Kosina <jkosina@xxxxxxx> wrote:
> On Thu, 1 Nov 2012, Jiri Kosina wrote:
>
>> > Commit 4fe9f8e203fdad1524c04beb390f3c6099781ed9 upstream
>> > Commit 57a38d925e665fcd729cd9ad4a75c84e11bd95c9 linux-stable
>> >
>> > This commit "HID: hidraw: don't deallocate memory when it is in use"
>> > prevents users to rmmod then insmod any hid special driver without
>> > either physically unplugging the device or without rmmod-ing the hid
>> > bus itself.
>> >
>> > When the user does a rmmod, hidinput_disconnect is called before
>> > hidraw_disconnect, thus, the hidraw device is still there, but the
>> > input one not. It leads to the fact that the device is not working
>> > anymore even if you call modprobe.
>> >
>> > Any idea to solve that?
>>
>> Guys, how about this?
I tested it against hid-multitouch and hid-logitech-dj and it's
working smoothly, thanks!
>>
>>
>> ---
>> drivers/hid/hidraw.c | 5 +++--
>> 1 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
>> index 17d15bb..fce4256 100644
>> --- a/drivers/hid/hidraw.c
>> +++ b/drivers/hid/hidraw.c
>> @@ -560,10 +560,11 @@ static void drop_ref(struct hidraw *hidraw, int exists_bit)
>> {
>> mutex_lock(&minors_lock);
>> if (exists_bit) {
>> - hid_hw_close(hidraw->hid);
>> hidraw->exist = 0;
>> - if (hidraw->open)
>> + if (hidraw->open) {
>> + hid_hw_close(hidraw->hid);
>> wake_up_interruptible(&hidraw->wait);
>> + }
>> } else {
>> --hidraw->open;
>> }
>
> So this seems to fix the problem with rmmod/modprobe, but the patch has
> apparently other problems. rmmoding special driver while reading from
> hidraw interface causes this:
>
> ------------[ cut here ]------------
> WARNING: at lib/list_debug.c:59 __list_del_entry+0xa4/0xd0()
> Hardware name: 7470BN2
> list_del corruption. prev->next should be ffff880036f97178, but was 6b6b6b6b6b6b6b6b
> Modules linked in: af_packet rfcomm bnep tun iptable_mangle xt_DSCP nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables xt
> e nf_conntrack iptable_filter ip_tables x_tables cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq mperf dm_mod
> m_intel kvm iwldvm mac80211 snd_hda_codec_conexant microcode usbhid sg iwlwifi pcspkr snd_hda_intel cfg80211 lpc_ich i2c_i801 mfd_c
> imer snd_page_alloc thinkpad_acpi rfkill wmi snd ac soundcore battery tpm_tis tpm tpm_bios autofs4 uhci_hcd ehci_hcd usbcore usb_co
> button edd fan processor ata_generic thermal thermal_sys [last unloaded: hid_cypress]
> Pid: 4725, comm: hexdump Not tainted 3.7.0-rc3-00008-g35fd3dc #157
> Call Trace:
> [<ffffffff812f95c4>] ? __list_del_entry+0xa4/0xd0
> [<ffffffff812f95c4>] ? __list_del_entry+0xa4/0xd0
> [<ffffffff810452fa>] warn_slowpath_common+0x7a/0xb0
> [<ffffffff810453d1>] warn_slowpath_fmt+0x41/0x50
> [<ffffffff812f95c4>] __list_del_entry+0xa4/0xd0
> [<ffffffff812f9601>] list_del+0x11/0x40
> [<ffffffff81454a23>] hidraw_release+0x33/0x50
> [<ffffffff8118cd0a>] __fput+0xca/0x2b0
> [<ffffffff8118cf49>] ____fput+0x9/0x10
> [<ffffffff8106b7a1>] task_work_run+0xb1/0xe0
> [<ffffffff8104c81e>] do_exit+0x1ee/0x4c0
> [<ffffffff810adcad>] ? trace_hardirqs_on_caller+0x12d/0x1b0
> [<ffffffff8104cb37>] do_group_exit+0x47/0xc0
> [<ffffffff8104cbc2>] sys_exit_group+0x12/0x20
> [<ffffffff8158a529>] system_call_fastpath+0x16/0x1b
> ---[ end trace 3bec13493e086171 ]---
>
This is weird, on my setup (kernel 3.6.2 + Henrik's patches + Ratan's
patch + your fix), I don't have this warning.
> As Ratan doesn't seem to be responsive and I don't have time to debug it
> as the moment, I'll just be reverting Ratan's patch for 3.7 completely.
Ok, you're the boss :)
Cheers,
Benjamin
>
> --
> Jiri Kosina
> SUSE Labs
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