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| author | Vasant Hegde <hegdevasant@linux.vnet.ibm.com> | 2017-10-10 15:07:46 +0530 |
|---|---|---|
| committer | Stewart Smith <stewart@linux.vnet.ibm.com> | 2017-10-11 19:30:30 +1100 |
| commit | 51146314dde7ec900e6a27d959b68f78ab2adad5 (patch) | |
| tree | cde4996fc7ba4b81696bec9d47c23d61a753d953 /hw/fsp | |
| parent | 65e912728ee18442c559445e83c4c74c1369c238 (diff) | |
| download | skiboot-51146314dde7ec900e6a27d959b68f78ab2adad5.zip skiboot-51146314dde7ec900e6a27d959b68f78ab2adad5.tar.gz skiboot-51146314dde7ec900e6a27d959b68f78ab2adad5.tar.bz2 | |
FSP/CONSOLE: Close SOL session during R/R
Presently we are not closing SOL and FW console sessions during R/R. Host will
continue to write to SOL buffer during FSP R/R. If there is heavy console write
operation happening during FSP R/R (like running `top` command inside console),
then at some point console buffer becomes full. fsp_console_write_buffer_space()
returns 0 (or less than required space to write data) to host. While one thread
is busy writing to console, if some other threads tries to write data to console
we may see RCU stalls (like below) in kernel.
kernel call trace:
------------------
[ 2082.828363] INFO: rcu_sched detected stalls on CPUs/tasks: { 32} (detected by 16, t=6002 jiffies, g=23154, c=23153, q=254769)
[ 2082.828365] Task dump for CPU 32:
[ 2082.828368] kworker/32:3 R running task 0 4637 2 0x00000884
[ 2082.828375] Workqueue: events dump_work_fn
[ 2082.828376] Call Trace:
[ 2082.828382] [c000000f1633fa00] [c00000000013b6b0] console_unlock+0x570/0x600 (unreliable)
[ 2082.828384] [c000000f1633fae0] [c00000000013ba34] vprintk_emit+0x2f4/0x5c0
[ 2082.828389] [c000000f1633fb60] [c00000000099e644] printk+0x84/0x98
[ 2082.828391] [c000000f1633fb90] [c0000000000851a8] dump_work_fn+0x238/0x250
[ 2082.828394] [c000000f1633fc60] [c0000000000ecb98] process_one_work+0x198/0x4b0
[ 2082.828396] [c000000f1633fcf0] [c0000000000ed3dc] worker_thread+0x18c/0x5a0
[ 2082.828399] [c000000f1633fd80] [c0000000000f4650] kthread+0x110/0x130
[ 2082.828403] [c000000f1633fe30] [c000000000009674] ret_from_kernel_thread+0x5c/0x68
Hence lets close SOL (and FW console) during FSP R/R.
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
(cherry picked from commit 9d1755179112071652bb4a317f9006da630ce25d)
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Diffstat (limited to 'hw/fsp')
| -rw-r--r-- | hw/fsp/fsp-console.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/hw/fsp/fsp-console.c b/hw/fsp/fsp-console.c index c20a9dd..aefab26 100644 --- a/hw/fsp/fsp-console.c +++ b/hw/fsp/fsp-console.c @@ -122,9 +122,6 @@ static void fsp_close_consoles(void) if (!fs->available) continue; - if (fs->rsrc_id == 0xffff) /* Get clarity from benh */ - continue; - lock(&fsp_con_lock); if (fs->open) { fs->open = false; |