linux

iv/linux

History

Johannes Berg 9f93bf0f19 iwlwifi: pcie: reschedule in long-running memory reads

[ Upstream commit 3d372c4edfd4dffb7dea71c6b096fb414782b776 ]

If we spin for a long time in memory reads that (for some reason in
hardware) take a long time, then we'll eventually get messages such
as

  watchdog: BUG: soft lockup - CPU#2 stuck for 24s! [kworker/2:2:272]

This is because the reading really does take a very long time, and
we don't schedule, so we're hogging the CPU with this task, at least
if CONFIG_PREEMPT is not set, e.g. with CONFIG_PREEMPT_VOLUNTARY=y.

Previously I misinterpreted the situation and thought that this was
only going to happen if we had interrupts disabled, and then fixed
this (which is good anyway, however), but that didn't always help;
looking at it again now I realized that the spin unlock will only
reschedule if CONFIG_PREEMPT is used.

In order to avoid this issue, change the code to cond_resched() if
we've been spinning for too long here.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Fixes: 04516706bb99 ("iwlwifi: pcie: limit memory read spin time")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/iwlwifi.20210115130253.217a9d6a6a12.If964cb582ab0aaa94e81c4ff3b279eaafda0fd3f@changeid
Signed-off-by: Sasha Levin <sashal@kernel.org>

2021-02-03 23:19:51 +01:00

admtek

adm80211: add checks for dma mapping errors

2017-11-30 08:39:13 +00:00

ath

wil6210: select CONFIG_CRC32

2021-01-17 13:57:55 +01:00

atmel

at76c50x-usb: Don't register led_trigger if usb_register_driver failed

2019-05-31 06:48:13 -07:00

broadcom

brcm80211: fix possible memleak in brcmf_proto_msgbuf_attach