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| author |   David Decotigny <ddecotig@google.com> | 2022-01-26 02:11:20 -0800 |
|---|---|---|
| committer |   Miquel Raynal <miquel.raynal@bootlin.com> | 2022-01-26 11:43:02 +0100 |
| commit | ca6263a0c9503d98b5aef04ed9b0f3971c66ec4e (patch) | |
| tree | 8e53a4c2079d158c2d2463699b7bdab3a29ddc37 | |
| parent | mtd: aspeed-smc: improve probe resilience (diff) | |
| download | linux-dev-ca6263a0c9503d98b5aef04ed9b0f3971c66ec4e.tar.xz linux-dev-ca6263a0c9503d98b5aef04ed9b0f3971c66ec4e.zip | |
mtd_blkdevs: avoid soft lockups with some mtd/spi devices
With some spi devices, the heavy cpu usage due to polling the spi
registers may lead to netdev timeouts, RCU complaints, etc. This can
be acute in the absence of CONFIG_PREEMPT. This patch allows to give
enough breathing room to avoid those incorrectly detected netdev
timeouts for example.
Example splat on 5.10.92:
[ 828.399306] rcu: INFO: rcu_sched self-detected stall on CPU
...
[ 828.419245] Task dump for CPU 1:
[ 828.422465] task:kworker/1:1H state:R running task on cpu 1 stack: 0 pid: 76 ppid: 2 flags:0x0000002a
[ 828.433132] Workqueue: kblockd blk_mq_run_work_fn
[ 828.437820] Call trace:
...
[ 828.512267] spi_mem_exec_op+0x4d0/0xde0
[ 828.516184] spi_mem_dirmap_read+0x180/0x39c
[ 828.520443] spi_nor_read_data+0x428/0x7e8
[ 828.524523] spi_nor_read+0x154/0x214
[ 828.528172] mtd_read_oob+0x440/0x714
[ 828.531815] mtd_read+0xac/0x120
[ 828.535030] mtdblock_readsect+0x178/0x230
[ 828.539102] mtd_blktrans_work+0x9fc/0xf28
[ 828.543177] mtd_queue_rq+0x1ac/0x2e4
[ 828.546827] blk_mq_dispatch_rq_list+0x2cc/0xa44
[ 828.551419] blk_mq_do_dispatch_sched+0xb0/0x7cc
[ 828.556010] __blk_mq_sched_dispatch_requests+0x350/0x494
[ 828.561372] blk_mq_sched_dispatch_requests+0xac/0xe4
[ 828.566387] __blk_mq_run_hw_queue+0x130/0x254
[ 828.570806] blk_mq_run_work_fn+0x50/0x60
[ 828.574814] process_one_work+0x578/0xf1c
[ 828.578814] worker_thread+0x5dc/0xea0
[ 828.582547] kthread+0x270/0x2d4
[ 828.585765] ret_from_fork+0x10/0x30
Signed-off-by: David Decotigny <ddecotig@google.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220126101120.676021-1-decot+git@google.com
| -rw-r--r-- | drivers/mtd/mtd_blkdevs.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index 243f28a3206b..64d2b093f114 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -158,6 +158,7 @@ static void mtd_blktrans_work(struct mtd_blktrans_dev *dev) } background_done = 0; + cond_resched(); spin_lock_irq(&dev->queue_lock); } } |