Linux kernel source tree
Go to file
Rob Clark 3e8b554114 soc: qcom: smsm: fix of_node refcnting problem
of_find_node_with_property() drops the reference to the 'from' node,
which eventually (after enough -EPROBE_DEFERs) drops the last reference
to the node causing all sorts of fun problems, and this nice splat.

  BUG: sleeping function called from invalid context at ../kernel/locking/mutex.c:747
  in_atomic(): 1, irqs_disabled(): 128, pid: 33, name: kworker/0:1
  4 locks held by kworker/0:1/33:
   #0:  ("events"){.+.+.+}, at: [<ffff0000080fa91c>] process_one_work+0x1a4/0x728
   #1:  (deferred_probe_work){+.+.+.}, at: [<ffff0000080fa91c>] process_one_work+0x1a4/0x728
   #2:  (&dev->mutex){......}, at: [<ffff000008676078>] __device_attach+0x30/0x168
   #3:  (devtree_lock){......}, at: [<ffff000008828fd0>] of_find_node_with_property+0x30/0xe0
  irq event stamp: 18976
  hardirqs last  enabled at (18975): [<ffff00000815794c>] __down_trylock_console_sem+0x74/0xb8
  hardirqs last disabled at (18976): [<ffff0000089e26d4>] _raw_spin_lock_irqsave+0x2c/0x78
  softirqs last  enabled at (16880): [<ffff0000080e0f00>] __do_softirq+0x580/0x640
  softirqs last disabled at (16871): [<ffff0000080e13a4>] irq_exit+0xe4/0x138
  CPU: 0 PID: 33 Comm: kworker/0:1 Tainted: G            E   4.12.0-rc5+ #1455
  Hardware name: qualcomm dragonboard410c/dragonboard410c, BIOS 2017.07-rc1-00234-g22fa70a-dirty 06/26/2017
  Workqueue: events deferred_probe_work_func
  Call trace:
  [<ffff000008089ee0>] dump_backtrace+0x0/0x230
  [<ffff00000808a134>] show_stack+0x24/0x30
  [<ffff0000084e1944>] dump_stack+0xac/0xe8
  [<ffff00000810d7e0>] ___might_sleep+0x150/0x230
  [<ffff00000810d918>] __might_sleep+0x58/0x90
  [<ffff0000089dde18>] __mutex_lock+0x50/0x870
  [<ffff0000089de674>] mutex_lock_nested+0x3c/0x50
  [<ffff000008388ae0>] kernfs_remove+0x30/0x50
  [<ffff00000838b720>] sysfs_remove_dir+0x58/0x70
  [<ffff0000084e393c>] kobject_del+0x1c/0x58
  [<ffff0000084e374c>] kobject_put+0xb4/0x208
  [<ffff00000882c364>] of_node_put+0x24/0x30
  [<ffff000008829018>] of_find_node_with_property+0x78/0xe0
  [<ffff000000aff5f4>] qcom_smsm_probe+0x194/0x720 [smsm]
  [<ffff0000086793b4>] platform_drv_probe+0x74/0x110
  [<ffff0000086765bc>] driver_probe_device+0x2b4/0x420
  [<ffff000008676920>] __device_attach_driver+0xd0/0x150
  [<ffff000008673e78>] bus_for_each_drv+0x68/0xa8
  [<ffff00000867611c>] __device_attach+0xd4/0x168
  [<ffff000008676a1c>] device_initial_probe+0x24/0x30
  [<ffff000008675380>] bus_probe_device+0xa0/0xa8
  [<ffff000008675948>] deferred_probe_work_func+0xb8/0xf8
  [<ffff0000080fa9d4>] process_one_work+0x25c/0x728
  [<ffff0000080faef4>] worker_thread+0x54/0x3d8
  [<ffff0000081031d8>] kthread+0x110/0x140
  [<ffff000008082d90>] ret_from_fork+0x10/0x40
  OF: ERROR: Bad of_node_put() on /smsm
  CPU: 0 PID: 33 Comm: kworker/0:1 Tainted: G        W   E   4.12.0-rc5+ #1455
  Hardware name: qualcomm dragonboard410c/dragonboard410c, BIOS 2017.07-rc1-00234-g22fa70a-dirty 06/26/2017
  Workqueue: events deferred_probe_work_func

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
2017-08-08 14:37:42 -05:00
arch Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-15 12:00:42 -07:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-07-11 15:36:52 -07:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-07-14 22:49:50 -07:00
Documentation This series converts a number of top-level documents to the RST format 2017-07-15 12:58:58 -07:00
drivers soc: qcom: smsm: fix of_node refcnting problem 2017-08-08 14:37:42 -05:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs Add wait_for_random_bytes() and get_random_*_wait() functions so that 2017-07-15 12:44:02 -07:00
include Add wait_for_random_bytes() and get_random_*_wait() functions so that 2017-07-15 12:44:02 -07:00
init random: do not ignore early device randomness 2017-07-12 16:26:00 -07:00
ipc ipc/util.h: update documentation for ipc_getref() and ipc_putref() 2017-07-12 16:26:02 -07:00
kernel Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-15 12:00:42 -07:00
lib Add wait_for_random_bytes() and get_random_*_wait() functions so that 2017-07-15 12:44:02 -07:00
mm Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-15 12:00:42 -07:00
net Add wait_for_random_bytes() and get_random_*_wait() functions so that 2017-07-15 12:44:02 -07:00
samples Merge branch 'akpm' (patches from Andrew) 2017-07-13 12:38:49 -07:00
scripts Kbuild updates for v4.13 (2nd) 2017-07-13 13:37:57 -07:00
security KEYS: DH: validate __spare field 2017-07-14 11:01:38 +10:00
sound sound fixes for 4.13-rc1 2017-07-14 12:44:00 -07:00
tools Merge branch 'akpm' (patches from Andrew) 2017-07-14 21:57:25 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Second batch of KVM updates for v4.13 2017-07-15 10:18:16 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2017-07-15 10:59:54 -07:00
Makefile Linux v4.13-rc1 2017-07-15 15:22:10 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.