[PATCH] spi: Fix hung task timeout when initialization fails
From: Ricardo Ribalda Delgado
Date: Thu May 01 2014 - 04:15:37 EST
If kthread_run on spi_init_queue() fails, spi_destroy_queue can lead to
hang timeout.
Before 786235eeba0e1e85e5cbbb9f97d1087ad03dfa21 kthread:
make kthread_create() killable" it was very unlikely that kthread_run
would fail, but after that patch a kill to modprobe can lead to this
kind of error. Udev kills modprobe after 30 seconds.
When this happens, spi_destroy_queue() leads to a hung process that
outputs a error message and avoids the computer to be halted/rebooted.
This bug is particulary critical on machines that relay on the spi
subsystem to hold a file system (MTD over SPI).
[ 95.900328] spi_master spi32765: failed to create message pump task
[ 95.900358] spi_master spi32765: problem initializing queue
[ 95.912333] qtec_pcie b0030000.pcie_bridge: Axi-pcie bridge supervisor
[ 240.463698] INFO: task udevd:129 blocked for more than 120 seconds.
[ 240.463733] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 240.463807] Call Trace:
[ 240.463968] [<ffffffff8178c22d>] wait_for_completion+0x1d/0x20
[ 240.464036] [<ffffffff8146c637>] spi_destroy_queue+0x27/0x60
[ 240.464050] [<ffffffff8146cc46>] spi_register_master+0x5d6/0x900
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx>
---
v2: Comment by Mark Brown:
-Improve commit message
drivers/spi/spi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 4eb9bf0..8331556 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1114,8 +1114,10 @@ static int spi_destroy_queue(struct spi_master *master)
return ret;
}
- flush_kthread_worker(&master->kworker);
- kthread_stop(master->kworker_task);
+ if (!IS_ERR(master->kworker_task)) {
+ flush_kthread_worker(&master->kworker);
+ kthread_stop(master->kworker_task);
+ }
return 0;
}
--
1.9.2
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