kernel.git/drivers/iio/industrialio-trigger.c, branch linux-5.4.y

iio: trigger: Fix reference counting

2021-12-14T13:49:05Z

commit a827a4984664308f13599a0b26c77018176d0c7c upstream. In viio_trigger_alloc() device_initialize() is used to set the initial reference count of the trigger to 1. Then another get_device() is called on trigger. This sets the reference count to 2 before the trigger is returned. iio_trigger_free(), which is the matching API to viio_trigger_alloc(), calls put_device() which decreases the reference count by 1. But the second reference count acquired in viio_trigger_alloc() is never dropped. As a result the iio_trigger_release() function is never called and the memory associated with the trigger is never freed. Since there is no reason for the trigger to start its lifetime with two reference counts just remove the extra get_device() in viio_trigger_alloc(). Fixes: 5f9c035cae18 ("staging:iio:triggers. Add a reference get to the core for triggers.") Signed-off-by: Lars-Peter Clausen Acked-by: Nuno Sá Link: https://lore.kernel.org/r/20211024092700.6844-2-lars@metafoo.de Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55Z

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

iio: trigger: Print an error if there is no available irq

2019-04-04T19:19:41Z

If there are more trigger consumers than CONFIG_IIO_CONSUMERS_PER_TRIGGER, iio_trigger_attach_poll_func will silently fail. Add an error message to inform the user that CONFIG_IIO_CONSUMERS_PER_TRIGGER limit might be exceeded. Signed-off-by: Mathieu Othacehe Signed-off-by: Jonathan Cameron

iio:trigger: Remove necessity to have a trig->ops structure.

2017-08-22T20:20:28Z

There are a few cases where none of the callbacks are supplied and the ops structure purely existed to provide the driver module. Given that is done differently now, we don't need to have a trig_ops structure. Allow for it not being there required a few additional sanity checks when trying check if particular callbacks are set. Signed-off-by: Jonathan Cameron Reviewed-by: Lars-Peter Clausen

iio: triggers: Use macros to avoid boilerplate assignment of owner.

2017-08-22T20:18:32Z

This trig_ops.owner assignment occurs in all trigger drivers and can be simply automated using a macro as has been done in many other places in the kernel. Signed-off-by: Jonathan Cameron Reviewed-by: Lars-Peter Clausen

iio: Use macro magic to avoid manual assign of driver_module

2017-08-22T19:03:14Z

Starting point in boiler plate reduction similar to that done for many similar cases elsewhere in the kernel. Signed-off-by: Jonathan Cameron Reviewed-by: Lars-Peter Clausen

iio: trigger: fix NULL pointer dereference in iio_trigger_write_current()

2017-05-21T11:36:59Z

In case oldtrig == trig == NULL (which happens when we set none trigger, when there is already none set) there is a NULL pointer dereference during iio_trigger_put(trig). Below is kernel output when this occurs: [ 26.741790] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 26.750179] pgd = cacc0000 [ 26.752936] [00000000] *pgd=8adc6835, *pte=00000000, *ppte=00000000 [ 26.759531] Internal error: Oops: 17 [#1] SMP ARM [ 26.764261] Modules linked in: usb_f_ncm u_ether usb_f_acm u_serial usb_f_fs libcomposite configfs evbug [ 26.773844] CPU: 0 PID: 152 Comm: synchro Not tainted 4.12.0-rc1 #2 [ 26.780128] Hardware name: Freescale i.MX6 Ultralite (Device Tree) [ 26.786329] task: cb1de200 task.stack: cac92000 [ 26.790892] PC is at iio_trigger_write_current+0x188/0x1f4 [ 26.796403] LR is at lock_release+0xf8/0x20c [ 26.800696] pc : [] lr : [] psr: 600d0013 [ 26.800696] sp : cac93e30 ip : cac93db0 fp : cac93e5c [ 26.812193] r10: c0e64fe8 r9 : 00000000 r8 : 00000001 [ 26.817436] r7 : cb190810 r6 : 00000010 r5 : 00000001 r4 : 00000000 [ 26.823982] r3 : 00000000 r2 : 00000000 r1 : cb1de200 r0 : 00000000 [ 26.830528] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 26.837683] Control: 10c5387d Table: 8acc006a DAC: 00000051 [ 26.843448] Process synchro (pid: 152, stack limit = 0xcac92210) [ 26.849475] Stack: (0xcac93e30 to 0xcac94000) [ 26.853857] 3e20: 00000001 c0736dac c054033c cae6b680 [ 26.862060] 3e40: cae6b680 00000000 00000001 cb3f8610 cac93e74 cac93e60 c054035c c0736db8 [ 26.870264] 3e60: 00000001 c054033c cac93e94 cac93e78 c029bf34 c0540348 00000000 00000000 [ 26.878469] 3e80: cb3f8600 cae6b680 cac93ed4 cac93e98 c029b320 c029bef0 00000000 00000000 [ 26.886672] 3ea0: 00000000 cac93f78 cb2d41fc caed3280 c029b214 cac93f78 00000001 000e20f8 [ 26.894874] 3ec0: 00000001 00000000 cac93f44 cac93ed8 c0221dcc c029b220 c0e1ca39 cb2d41fc [ 26.903079] 3ee0: cac93f04 cac93ef0 c0183ef0 c0183ab0 cb2d41fc 00000000 cac93f44 cac93f08 [ 26.911282] 3f00: c0225eec c0183ebc 00000001 00000000 c0223728 00000000 c0245454 00000001 [ 26.919485] 3f20: 00000001 caed3280 000e20f8 cac93f78 000e20f8 00000001 cac93f74 cac93f48 [ 26.927690] 3f40: c0223680 c0221da4 c0246520 c0245460 caed3283 caed3280 00000000 00000000 [ 26.935893] 3f60: 000e20f8 00000001 cac93fa4 cac93f78 c0224520 c02235e4 00000000 00000000 [ 26.944096] 3f80: 00000001 000e20f8 00000001 00000004 c0107f84 cac92000 00000000 cac93fa8 [ 26.952299] 3fa0: c0107de0 c02244e8 00000001 000e20f8 0000000e 000e20f8 00000001 fbad2484 [ 26.960502] 3fc0: 00000001 000e20f8 00000001 00000004 beb6b698 00064260 0006421c beb6b4b4 [ 26.968705] 3fe0: 00000000 beb6b450 b6f219a0 b6e2f268 800d0010 0000000e cac93ff4 cac93ffc [ 26.976896] Backtrace: [ 26.979388] [] (iio_trigger_write_current) from [] (dev_attr_store+0x20/0x2c) [ 26.988289] r10:cb3f8610 r9:00000001 r8:00000000 r7:cae6b680 r6:cae6b680 r5:c054033c [ 26.996138] r4:c0736dac r3:00000001 [ 26.999747] [] (dev_attr_store) from [] (sysfs_kf_write+0x50/0x54) [ 27.007686] r5:c054033c r4:00000001 [ 27.011290] [] (sysfs_kf_write) from [] (kernfs_fop_write+0x10c/0x224) [ 27.019579] r7:cae6b680 r6:cb3f8600 r5:00000000 r4:00000000 [ 27.025271] [] (kernfs_fop_write) from [] (__vfs_write+0x34/0x120) [ 27.033214] r10:00000000 r9:00000001 r8:000e20f8 r7:00000001 r6:cac93f78 r5:c029b214 [ 27.041059] r4:caed3280 [ 27.043622] [] (__vfs_write) from [] (vfs_write+0xa8/0x170) [ 27.050959] r9:00000001 r8:000e20f8 r7:cac93f78 r6:000e20f8 r5:caed3280 r4:00000001 [ 27.058731] [] (vfs_write) from [] (SyS_write+0x44/0x98) [ 27.065806] r9:00000001 r8:000e20f8 r7:00000000 r6:00000000 r5:caed3280 r4:caed3283 [ 27.073582] [] (SyS_write) from [] (ret_fast_syscall+0x0/0x1c) [ 27.081179] r9:cac92000 r8:c0107f84 r7:00000004 r6:00000001 r5:000e20f8 r4:00000001 [ 27.088947] Code: 1a000009 e1a04009 e3a06010 e1a05008 (e5943000) [ 27.095244] ---[ end trace 06d1dab86d6e6bab ]--- To fix that problem call iio_trigger_put(trig) only when trig is not NULL. Fixes: d5d24bcc0a10 ("iio: trigger: close race condition in acquiring trigger reference") Signed-off-by: Marcin Niestroj Cc: Signed-off-by: Jonathan Cameron

iio: trigger: clean up viio_trigger_alloc()

2017-01-22T13:37:34Z

1) Reverse the test for kmalloc() failure so we can pull everything back one tab. 2) Use gotos for unwinding. 3) Some of the extra line breaks for the 80 character limit are no longer needed so we can remove them. Signed-off-by: Dan Carpenter Signed-off-by: Jonathan Cameron

iio: industrialio-trigger: constify device_type structures

2017-01-22T13:21:42Z

Declare device_type structure as const as it is only stored in the type field of a device structure. This field is of type const, so add const to declaration of device_type structure. File size before: text data bss dec hex filename 5389 208 48 5645 160d iio/industrialio-trigger.o File size after: text data bss dec hex filename 5453 176 48 5677 162d iio/industrialio-trigger.o Signed-off-by: Bhumika Goyal Signed-off-by: Jonathan Cameron

iio: trigger: close race condition in acquiring trigger reference

2017-01-22T13:21:41Z

In iio_trigger_write_current() we find the trigger we want while holding mutex on the list of triggers, but we don't actually do a get on it while holding mutex. We wait until further validations are completed and we're sure it's the one we want. Race condition is that it could be freed by the time we do the get. Solution is to grab the trigger (iio_trigger_get) as soon as we find it while holding mutex on the list of triggers. If later we decide it's not the right one, put it back. (iio_trigger_put). Signed-off-by: Alison Schofield Suggested-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron