mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-04-03 12:05:13 +02:00
629be44a1f
[ Upstream commit9910159f06] When one iio device is a consumer of another, it is possible that the ->info_exist_lock of both ends up being taken when reading the value of the consumer device. Since they currently belong to the same lockdep class (being initialized in a single location with mutex_init()), that results in a lockdep warning CPU0 ---- lock(&iio_dev_opaque->info_exist_lock); lock(&iio_dev_opaque->info_exist_lock); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by sensors/414: #0: c31fd6dc (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0x44/0x4e4 #1: c4f5a1c4 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x1c/0xac #2: c2827548 (kn->active#34){.+.+}-{0:0}, at: kernfs_seq_start+0x30/0xac #3:c1dd2b68(&iio_dev_opaque->info_exist_lock){+.+.}-{3:3}, at: iio_read_channel_processed_scale+0x24/0xd8 stack backtrace: CPU: 0 UID: 0 PID: 414 Comm: sensors Not tainted 6.17.11 #5 NONE Hardware name: Generic AM33XX (Flattened Device Tree) Call trace: unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x44/0x60 dump_stack_lvl from print_deadlock_bug+0x2b8/0x334 print_deadlock_bug from __lock_acquire+0x13a4/0x2ab0 __lock_acquire from lock_acquire+0xd0/0x2c0 lock_acquire from __mutex_lock+0xa0/0xe8c __mutex_lock from mutex_lock_nested+0x1c/0x24 mutex_lock_nested from iio_read_channel_raw+0x20/0x6c iio_read_channel_raw from rescale_read_raw+0x128/0x1c4 rescale_read_raw from iio_channel_read+0xe4/0xf4 iio_channel_read from iio_read_channel_processed_scale+0x6c/0xd8 iio_read_channel_processed_scale from iio_hwmon_read_val+0x68/0xbc iio_hwmon_read_val from dev_attr_show+0x18/0x48 dev_attr_show from sysfs_kf_seq_show+0x80/0x110 sysfs_kf_seq_show from seq_read_iter+0xdc/0x4e4 seq_read_iter from vfs_read+0x238/0x2e4 vfs_read from ksys_read+0x6c/0xec ksys_read from ret_fast_syscall+0x0/0x1c Just as the mlock_key already has its own lockdep class, add a lock_class_key for the info_exist mutex. Note that this has in theory been a problem since before IIO first left staging, but it only occurs when a chain of consumers is in use and that is not often done. Fixes:ac917a8111("staging:iio:core set the iio_dev.info pointer to null on unregister under lock.") Signed-off-by: Rasmus Villemoes <ravi@prevas.dk> Reviewed-by: Peter Rosin <peda@axentia.se> Cc: <stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
85 lines
3.3 KiB
C
85 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
|
|
#ifndef _INDUSTRIAL_IO_OPAQUE_H_
|
|
#define _INDUSTRIAL_IO_OPAQUE_H_
|
|
|
|
/**
|
|
* struct iio_dev_opaque - industrial I/O device opaque information
|
|
* @indio_dev: public industrial I/O device information
|
|
* @id: used to identify device internally
|
|
* @currentmode: operating mode currently in use, may be eventually
|
|
* checked by device drivers but should be considered
|
|
* read-only as this is a core internal bit
|
|
* @driver_module: used to make it harder to undercut users
|
|
* @mlock: lock used to prevent simultaneous device state changes
|
|
* @mlock_key: lockdep class for iio_dev lock
|
|
* @info_exist_lock: lock to prevent use during removal
|
|
* @info_exist_key: lockdep class for info_exist lock
|
|
* @trig_readonly: mark the current trigger immutable
|
|
* @event_interface: event chrdevs associated with interrupt lines
|
|
* @attached_buffers: array of buffers statically attached by the driver
|
|
* @attached_buffers_cnt: number of buffers in the array of statically attached buffers
|
|
* @buffer_ioctl_handler: ioctl() handler for this IIO device's buffer interface
|
|
* @buffer_list: list of all buffers currently attached
|
|
* @channel_attr_list: keep track of automatically created channel
|
|
* attributes
|
|
* @chan_attr_group: group for all attrs in base directory
|
|
* @ioctl_handlers: ioctl handlers registered with the core handler
|
|
* @groups: attribute groups
|
|
* @groupcounter: index of next attribute group
|
|
* @legacy_scan_el_group: attribute group for legacy scan elements attribute group
|
|
* @legacy_buffer_group: attribute group for legacy buffer attributes group
|
|
* @bounce_buffer: for devices that call iio_push_to_buffers_with_timestamp_unaligned()
|
|
* @bounce_buffer_size: size of currently allocate bounce buffer
|
|
* @scan_index_timestamp: cache of the index to the timestamp
|
|
* @clock_id: timestamping clock posix identifier
|
|
* @chrdev: associated character device
|
|
* @flags: file ops related flags including busy flag.
|
|
* @debugfs_dentry: device specific debugfs dentry
|
|
* @cached_reg_addr: cached register address for debugfs reads
|
|
* @read_buf: read buffer to be used for the initial reg read
|
|
* @read_buf_len: data length in @read_buf
|
|
*/
|
|
struct iio_dev_opaque {
|
|
struct iio_dev indio_dev;
|
|
int currentmode;
|
|
int id;
|
|
struct module *driver_module;
|
|
struct mutex mlock;
|
|
struct lock_class_key mlock_key;
|
|
struct mutex info_exist_lock;
|
|
struct lock_class_key info_exist_key;
|
|
bool trig_readonly;
|
|
struct iio_event_interface *event_interface;
|
|
struct iio_buffer **attached_buffers;
|
|
unsigned int attached_buffers_cnt;
|
|
struct iio_ioctl_handler *buffer_ioctl_handler;
|
|
struct list_head buffer_list;
|
|
struct list_head channel_attr_list;
|
|
struct attribute_group chan_attr_group;
|
|
struct list_head ioctl_handlers;
|
|
const struct attribute_group **groups;
|
|
int groupcounter;
|
|
struct attribute_group legacy_scan_el_group;
|
|
struct attribute_group legacy_buffer_group;
|
|
void *bounce_buffer;
|
|
size_t bounce_buffer_size;
|
|
|
|
unsigned int scan_index_timestamp;
|
|
clockid_t clock_id;
|
|
struct cdev chrdev;
|
|
unsigned long flags;
|
|
|
|
#if defined(CONFIG_DEBUG_FS)
|
|
struct dentry *debugfs_dentry;
|
|
unsigned cached_reg_addr;
|
|
char read_buf[20];
|
|
unsigned int read_buf_len;
|
|
#endif
|
|
};
|
|
|
|
#define to_iio_dev_opaque(_indio_dev) \
|
|
container_of((_indio_dev), struct iio_dev_opaque, indio_dev)
|
|
|
|
#endif
|