Hi,
Apologies for a possible stupid question.
On 20/03/2019 17:15, Sebastian Andrzej Siewior wrote:
- Applied John Ogness' prinkt rework. One visible change is the
output during boot. Under the hood and for RT: By default, output
that is created at KERN_WARN[0] or higher is printed immediately if the
console supports "atomic" print (currently the 8250 driver does).
This output is printed immediately (and visible) even from IRQ-off
or preempt-disabled regions which wasn't the case earlier. This will
raise the latency at run-time *but* there should be no WARNING,
ERROR or PANIC messages at run-time on a fully working system.
Messages with lower severity are printed "later" by a kthread.
Using 5.0.3-rt1, I get some warning message completely mangled with the rest of
the output (e.g systemd message) but also between them. Some excerpt of a 500
lines lockdep warning (AFAICT the printk is not related to the printk code):
[ 52.294547] 005: ... which became HARDIRQ-irq-unsafe at:
[ 52.294553] 005: ...
[ 52.294554] 005: lock_acquire+0xf8/0x318
[ OK ] Reached target
t_spin_lock+0x48/0x70 lock_acquire+0xf8/0x318
[0;1;39mRemote File Systems.[ 52.294570] 005: iommu_dma_map_msi_msg+0x5c/0x1
[ 52.296824] 005: CPU: 5 PID: 2108 Comm: ip Not tainted 5.0.3-rt1-00007-g42ede
9a0fed6 #4312] 005: __sys_sendmsg+0x68/0xb8
I understand the new series add support for "atomic" print. So I am wondering
whether this issue is related to it? Is there any advice to prevent the mangling?
Cheers,
--
Julien Grall
