On 12/27/17 12:09 AM, Masami Hiramatsu wrote:
On Tue, 26 Dec 2017 18:12:56 -0800
Alexei Starovoitov <alexei.starovoi...@gmail.com> wrote:
On Tue, Dec 26, 2017 at 04:48:25PM +0900, Masami Hiramatsu wrote:
Support in-kernel fault-injection framework via debugfs.
This allows you to inject a conditional error to specified
function using debugfs interfaces.
Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
---
Documentation/fault-injection/fault-injection.txt | 5 +
kernel/Makefile | 1
kernel/fail_function.c | 169 +++++++++++++++++++++
lib/Kconfig.debug | 10 +
4 files changed, 185 insertions(+)
create mode 100644 kernel/fail_function.c
diff --git a/Documentation/fault-injection/fault-injection.txt
b/Documentation/fault-injection/fault-injection.txt
index 918972babcd8..6243a588dd71 100644
--- a/Documentation/fault-injection/fault-injection.txt
+++ b/Documentation/fault-injection/fault-injection.txt
@@ -30,6 +30,11 @@ o fail_mmc_request
injects MMC data errors on devices permitted by setting
debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request
+o fail_function
+
+ injects error return on specific functions by setting debugfs entries
+ under /sys/kernel/debug/fail_function. No boot option supported.
I like it.
Could you document it a bit better?
Yes, I will do in next series.
In particular retval is configurable, but without an example no one
will be able to figure out how to use it.
Ah, right. BTW, as I pointed in the covermail, should we store the
expected error value range into the injectable list? e.g.
ALLOW_ERROR_INJECTION(open_ctree, -1, -MAX_ERRNO)
And provide APIs to check/get it.
I'm afraid such check would be too costly.
Right now we have only two functions marked but I expect hundreds more
will be added in the near future as soon as developers realize the
potential of such error injection.
All of ALLOW_ERROR_INJECTION marks add 8 byte overhead each to .data.
Multiple by 1k and we have 8k of data spent on marks.
If we add max/min range marks that doubles it for very little use.
I think marking function only is enough.
