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fault-inject: parse as natural 1-based value for fail-nth write interface 

The value written to fail-nth file is parsed as 0-based.  Parsing as
one-based is more natural to understand and it enables to cancel the
previous setup by simply writing '0'.

This change also converts task->fail_nth from signed to unsigned int.

Link: http://lkml.kernel.org/r/1491490561-10485-3-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Akinobu Mita 2017-07-14 14:49:52 -07:00 committed by Linus Torvalds
parent ecaad81ca0
commit 9049f2f6e7
3 changed files with 8 additions and 10 deletions
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7
Documentation/fault-injection/fault-injection.txt
View File

@ -138,8 +138,8 @@ o proc entries
- /proc/self/task/<current-tid>/fail-nth:
Write to this file of integer N makes N-th call in the current task fail
(N is 0-based). Read from this file returns a single char 'Y' or 'N'
Write to this file of integer N makes N-th call in the task fail.
Read from this file returns a single char 'Y' or 'N'
that says if the fault setup with a previous write to this file was
injected or not, and disables the fault if it wasn't yet injected.
Note that this file enables all types of faults (slab, futex, etc).
@ -320,7 +320,7 @@ int main()
system("echo N > /sys/kernel/debug/failslab/ignore-gfp-wait");
sprintf(buf, "/proc/self/task/%ld/fail-nth", syscall(SYS_gettid));
fail_nth = open(buf, O_RDWR);
for (i = 0;; i++) {
for (i = 1;; i++) {
sprintf(buf, "%d", i);
write(fail_nth, buf, strlen(buf));
res = socketpair(AF_LOCAL, SOCK_STREAM, 0, fds);
@ -339,7 +339,6 @@ int main()
An example output:
0-th fault Y: res=-1/23
1-th fault Y: res=-1/23
2-th fault Y: res=-1/23
3-th fault Y: res=-1/12

9
fs/proc/base.c
View File

@ -1360,7 +1360,8 @@ static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task;
int err, n;
int err;
unsigned int n;
task = get_proc_task(file_inode(file));
if (!task)
@ -1368,12 +1369,10 @@ static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
put_task_struct(task);
if (task != current)
return -EPERM;
err = kstrtoint_from_user(buf, count, 0, &n);
err = kstrtouint_from_user(buf, count, 0, &n);
if (err)
return err;
if (n < 0 || n == INT_MAX)
return -EINVAL;
current->fail_nth = n + 1;
current->fail_nth = n;
return count;
}

2
include/linux/sched.h
View File

@ -974,7 +974,7 @@ struct task_struct {
#ifdef CONFIG_FAULT_INJECTION
int make_it_fail;
int fail_nth;
unsigned int fail_nth;
#endif
/*
* When (nr_dirtied >= nr_dirtied_pause), it's time to call