From: Lee Jones <lee.jones@linaro.org>
To: Andreas Kemnade <andreas@kemnade.info>
Cc: linux-kernel@vger.kernel.org, j.neuschaefer@gmx.net,
m.felsch@pengutronix.de
Subject: Re: [PATCH v2] mfd: rn5t618: Make restart handler atomic safe
Date: Wed, 22 Jul 2020 10:52:28 +0100 [thread overview]
Message-ID: <20200722095228.GJ621928@dell> (raw)
In-Reply-To: <20200721073402.22925-1-andreas@kemnade.info>
On Tue, 21 Jul 2020, Andreas Kemnade wrote:
> The restart handler is executed during the shutdown phase which is
> atomic/irq-less. The i2c framework supports atomic transfers since
> commit 63b96983a5dd ("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>
> ---
> Changes in v2:
> - keep comments
>
> drivers/mfd/rn5t618.c | 43 +++++++++++++++++++++++++++++++++----------
> 1 file changed, 33 insertions(+), 10 deletions(-)
Applied, thanks.
--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog
prev parent reply other threads:[~2020-07-22 9:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-21 7:34 Andreas Kemnade
2020-07-22 9:52 ` Lee Jones [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200722095228.GJ621928@dell \
--to=lee.jones@linaro.org \
--cc=andreas@kemnade.info \
--cc=j.neuschaefer@gmx.net \
--cc=linux-kernel@vger.kernel.org \
--cc=m.felsch@pengutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®