The patch titled
serial8250: ratelimit "too much work" error
has been added to the -mm tree. Its filename is
serial8250-ratelimit-too-much-work-error.patch
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See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: serial8250: ratelimit "too much work" error
From: Daniel Drake <dsd@xxxxxxxxxx>
Running a serial console, if too many kernel messages are generated within
a short time causing a lot of serial I/O, the 8250 driver will generate
another kernel message reporting this, which just adds to the I/O. It has
a cascading effect and quickly results the system being brought to its knees
by a flood of "too much work" messages.
Ratelimit the error message to avoid this.
Signed-off-by: Daniel Drake <dsd@xxxxxxxxxx>
Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/serial/8250.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff -puN drivers/serial/8250.c~serial8250-ratelimit-too-much-work-error drivers/serial/8250.c
--- a/drivers/serial/8250.c~serial8250-ratelimit-too-much-work-error
+++ a/drivers/serial/8250.c
@@ -1606,8 +1606,9 @@ static irqreturn_t serial8250_interrupt(
if (l == i->head && pass_counter++ > PASS_LIMIT) {
/* If we hit this, we're dead. */
- printk(KERN_ERR "serial8250: too much work for "
- "irq%d\n", irq);
+ if (printk_ratelimit())
+ printk(KERN_ERR "serial8250: too much work for "
+ "irq%d\n", irq);
break;
}
} while (l != end);
_
Patches currently in -mm which might be from dsd@xxxxxxxxxx are
linux-next.patch
serial8250-ratelimit-too-much-work-error.patch
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