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Andreas Kemnade cf84dc0bb4 mfd: rn5t618: Make restart handler atomic safe
The restart handler is executed during the shutdown phase which is
atomic/irq-less. The i2c framework supports atomic transfers since
commit 63b96983a5 ("i2c: core: introduce callbacks for atomic
transfers") to address this use case. Using i2c regmap in that
situation is not allowed:

[  165.177465] [ BUG: Invalid wait context ]
[  165.181479] 5.8.0-rc3-00003-g0e9088558027-dirty #11 Not tainted
[  165.187400] -----------------------------
[  165.191410] systemd-shutdow/1 is trying to lock:
[  165.196030] d85b4438 (rn5t618:170:(&rn5t618_regmap_config)->lock){+.+.}-{3:3}, at: regmap_update_bits_base+0x30/0x70
[  165.206573] other info that might help us debug this:
[  165.211625] context-{4:4}
[  165.214248] 2 locks held by systemd-shutdow/1:
[  165.218691]  #0: c131c47c (system_transition_mutex){+.+.}-{3:3}, at: __do_sys_reboot+0x90/0x204
[  165.227405]  #1: c131efb4 (rcu_read_lock){....}-{1:2}, at: __atomic_notifier_call_chain+0x0/0x118
[  165.236288] stack backtrace:
[  165.239174] CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.8.0-rc3-00003-g0e9088558027-dirty #11
[  165.248220] Hardware name: Freescale i.MX6 SoloLite (Device Tree)
[  165.254330] [<c0112110>] (unwind_backtrace) from [<c010bfa0>] (show_stack+0x10/0x14)
[  165.262084] [<c010bfa0>] (show_stack) from [<c058093c>] (dump_stack+0xe8/0x120)
[  165.269407] [<c058093c>] (dump_stack) from [<c01835a4>] (__lock_acquire+0x81c/0x2ca0)
[  165.277246] [<c01835a4>] (__lock_acquire) from [<c0186344>] (lock_acquire+0xe4/0x490)
[  165.285090] [<c0186344>] (lock_acquire) from [<c0c98638>] (__mutex_lock+0x74/0x954)
[  165.292756] [<c0c98638>] (__mutex_lock) from [<c0c98f34>] (mutex_lock_nested+0x1c/0x24)
[  165.300769] [<c0c98f34>] (mutex_lock_nested) from [<c07593ec>] (regmap_update_bits_base+0x30/0x70)
[  165.309741] [<c07593ec>] (regmap_update_bits_base) from [<c076b838>] (rn5t618_trigger_poweroff_sequence+0x34/0x64)
[  165.320097] [<c076b838>] (rn5t618_trigger_poweroff_sequence) from [<c076b874>] (rn5t618_restart+0xc/0x2c)
[  165.329669] [<c076b874>] (rn5t618_restart) from [<c01514f8>] (notifier_call_chain+0x48/0x80)
[  165.338113] [<c01514f8>] (notifier_call_chain) from [<c01516a8>] (__atomic_notifier_call_chain+0x70/0x118)
[  165.347770] [<c01516a8>] (__atomic_notifier_call_chain) from [<c0151768>] (atomic_notifier_call_chain+0x18/0x20)
[  165.357949] [<c0151768>] (atomic_notifier_call_chain) from [<c010a828>] (machine_restart+0x68/0x80)
[  165.367001] [<c010a828>] (machine_restart) from [<c0153224>] (__do_sys_reboot+0x11c/0x204)
[  165.375272] [<c0153224>] (__do_sys_reboot) from [<c0100080>] (ret_fast_syscall+0x0/0x28)
[  165.383364] Exception stack(0xd80a5fa8 to 0xd80a5ff0)
[  165.388420] 5fa0:                   00406948 00000000 fee1dead 28121969 01234567 73299b00
[  165.396602] 5fc0: 00406948 00000000 00000000 00000058 be91abc8 00000000 be91ab60 004056f8
[  165.404781] 5fe0: 00000058 be91aabc b6ed4d45 b6e56746

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-08-13 07:49:56 +01:00
arch Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
block Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux 2020-06-10 14:46:54 -07:00
Documentation dt-bindings: mfd: st,stmfx: Remove I2C unit name 2020-08-13 07:49:46 +01:00
drivers mfd: rn5t618: Make restart handler atomic safe 2020-08-13 07:49:56 +01:00
fs for-5.8-part2-tag 2020-06-14 09:47:25 -07:00
include mfd: da9063: Add support for latest DA silicon revision 2020-08-13 07:49:50 +01:00
init Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel Add additional LSM hooks for SafeSetID 2020-06-14 11:39:31 -07:00
lib Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
samples binderfs: add gitignore for generated sample program 2020-06-13 13:41:24 -07:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
security Add additional LSM hooks for SafeSetID 2020-06-14 11:39:31 -07:00
sound Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt MIPS: 2020-06-12 11:05:52 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore modpost: generate vmlinux.symvers and reuse it for the second modpost 2020-06-06 23:38:12 +09:00
.mailmap A fair amount of stuff this time around, dominated by yet another massive 2020-06-01 15:45:27 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Add entry for ROHM Power Management ICs 2020-06-30 08:10:45 +01:00
Makefile Linux 5.8-rc1 2020-06-14 12:45:04 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.