Normally, when input device supporting force feedback effects is being
destroyed, we try to "flush" currently playing effects, so that the
physical device does not continue vibrating (or executing other effects).
Unfortunately this does not work well for uinput as flushing of the effects
deadlocks with the destroy action:
- if device is being destroyed because the file descriptor is being closed,
then there is noone to even service FF requests;
- if device is being destroyed because userspace sent UI_DEV_DESTROY,
while theoretically it could be possible to service FF requests,
userspace is unlikely to do so (they'd need to make sure FF handling
happens on a separate thread) even if kernel solves the issue with FF
ioctls deadlocking with UI_DEV_DESTROY ioctl on udev->mutex.
To avoid lockups like the one below, let's install a custom input device
flush handler, and avoid trying to flush force feedback effects when we
destroying the device, and instead rely on uinput to shut off the device
properly.
NMI watchdog: Watchdog detected hard LOCKUP on cpu 3
...
<<EOE>> [<ffffffff817a0307>] _raw_spin_lock_irqsave+0x37/0x40
[<ffffffff810e633d>] complete+0x1d/0x50
[<ffffffffa00ba08c>] uinput_request_done+0x3c/0x40 [uinput]
[<ffffffffa00ba587>] uinput_request_submit.part.7+0x47/0xb0 [uinput]
[<ffffffffa00bb62b>] uinput_dev_erase_effect+0x5b/0x76 [uinput]
[<ffffffff815d91ad>] erase_effect+0xad/0xf0
[<ffffffff815d929d>] flush_effects+0x4d/0x90
[<ffffffff815d4cc0>] input_flush_device+0x40/0x60
[<ffffffff815daf1c>] evdev_cleanup+0xac/0xc0
[<ffffffff815daf5b>] evdev_disconnect+0x2b/0x60
[<ffffffff815d74ac>] __input_unregister_device+0xac/0x150
[<ffffffff815d75f7>] input_unregister_device+0x47/0x70
[<ffffffffa00bac45>] uinput_destroy_device+0xb5/0xc0 [uinput]
[<ffffffffa00bb2de>] uinput_ioctl_handler.isra.9+0x65e/0x740 [uinput]
[<ffffffff811231ab>] ? do_futex+0x12b/0xad0
[<ffffffffa00bb3f8>] uinput_ioctl+0x18/0x20 [uinput]
[<ffffffff81241248>] do_vfs_ioctl+0x298/0x480
[<ffffffff81337553>] ? security_file_ioctl+0x43/0x60
[<ffffffff812414a9>] SyS_ioctl+0x79/0x90
[<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71
Reported-by: Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>
Reported-by: Clément VUCHENER <clement.vuchener@gmail.com>
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=193741
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
There is an undocumented upper bound for the total number of ff effects:
FF_GAIN (= 96).
This can be found as follows:
- user: write(EV_FF, effect_id, iterations)
calls kernel: ff->playback(effect_id, ...): starts effect "effect_id"
- user: write(EV_FF, FF_GAIN, gain)
calls kernel: ff->set_gain(gain, ...): sets gain
A collision occurs when effect_id equals FF_GAIN.
According to input_ff_event(),
FF_GAIN is the smallest value where a collision occurs.
Therefore the greatest safe value for effect_id is FF_GAIN - 1,
and thus the total number of effects should never exceed FF_GAIN.
Define FF_MAX_EFFECTS as FF_GAIN and check on this limit in ff-core.
Signed-off-by: Elias Vanderstuyft <elias.vds@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
My static checker complains that "value" comes from the user in
evdev_do_ioctl() and we check that it's not too large here but we don't
check that it's negative. It's harmless because the ->set_gain() and
->set_autocenter() functions truncate it to a valid u16 value, but we
may as well fix it just to make the static checker happy.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Use for_each_set_bit to check for set bits in bitmap
as it is more efficient than checking individual bits.
Signed-off-by: Anshul Garg <aksgarg1989@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
The problem here is that max_effects can wrap on 32 bits systems.
We'd allocate a smaller amount of data than sizeof(struct ff_device).
The call to kcalloc() on the next line would fail but it would write
the NULL return outside of the memory we just allocated causing data
corruption.
The call path is that uinput_setup_device() get ->ff_effects_max from
the user and sets the value in the ->private_data struct. From there
it is:
-> uinput_ioctl_handler()
-> uinput_create_device()
-> input_ff_create(dev, udev->ff_effects_max);
I've also changed ff_effects_max so it's an unsigned int instead of
a signed int as a cleanup.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Function name is input_ff_destroy() and not input_ff_free()
Signed-off-by: Roger Quadros <roger.quadros@nokia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Now that input core acquires dev->event_lock spinlock and disables
interrupts when propagating input events, using spin_lock_bh() in
ff-memless driver is not allowed. Actually, the timer_lock itself
is not needed anymore, we should simply use dev->event_lock
as well.
Also do a small cleanup in force-feedback core.
Reported-by: kerneloops.org
Reported-by: http://www.kerneloops.org/searchweek.php?search=ml_ff_set_gain
Reported-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Commit 656acd2bbc ("Input: fix locking in
force-feedback core") causes the following regression on m68k:
| linux/drivers/input/ff-core.c: In function 'input_ff_upload':
| linux/drivers/input/ff-core.c:172: error: dereferencing pointer to incomplete type
| linux/drivers/input/ff-core.c: In function 'erase_effect':
| linux/drivers/input/ff-core.c:197: error: dereferencing pointer to incomplete type
| linux/drivers/input/ff-core.c:204: error: dereferencing pointer to incomplete type
| make[4]: *** [drivers/input/ff-core.o] Error 1
As the incomplete type is `struct task_struct', including <linux/sched.h> fixes
it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The newly added event_lock spinlock in the input core disallows sleeping
and therefore using mutexes in event handlers. Convert force-feedback
core to rely on event_lock instead of mutex to protect slots allocated
for fore-feedback effects. The original mutex is still used to serialize
uploading and erasing of effects.
Reported-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Make sure that requested effect id is not out of range for the
device and that effect is present before requesting device to
play it.
Reported-by: Jan Kratochvil <honza@jikos.cz>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Add input subsystem to kernel-api docbook.
Enhance some function and parameter comments.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Implement a new force feedback interface, in which all non-driver-specific
operations are separated to a common module. This includes handling effect
type validations, locking, etc.
The effects are now file descriptor specific instead of the previous strange
half-process half-fd specific behaviour. The effect memory of devices is not
emptied if the root user opens and closes the device while another user is
using effects. This is a minor change and most likely no force feedback
aware programs are affected by this negatively.
Otherwise the userspace interface is left unaltered.
Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
