lkml.org 
[lkml]   [2012]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: I finally prepared a testcase for read(inotify_fd) getting EINTR on PTRACE_ATTACH
On 02/10/2012 04:09 PM, Oleg Nesterov wrote:
> On 02/10, Oleg Nesterov wrote:
>> At first glance this looks obvious? I never used inotify and I never
>> looked into fs/notify/inotify/, but it seems that inotify_read() simply
>> returns -EINTR if signal_pending() and doesn't implement restarts.
>>
>> Probably this trivial change
>>
>> --- x/fs/notify/inotify/inotify_user.c
>> +++ x/fs/notify/inotify/inotify_user.c
>> @@ -264,7 +264,7 @@ static ssize_t inotify_read(struct file
>> ret = -EAGAIN;
>> if (file->f_flags& O_NONBLOCK)
>> break;
>> - ret = -EINTR;
>> + ret = -ERESTARTSYS;
>> if (signal_pending(current))
>> break;
>>
>>
>> makes sense.
>
> except I meant -ERESTARTNOHAND to avoid the behavioural change.

I run-tested the fix. It works: testcase no longer fails
(modulo incorrect logic in the testcase which wase not working
properly on "no bug detected" code path. Fixed one:
http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/eintr-on-attach.c?cvsroot=systemtap
)

I'm not sure inotify really wants to deviate from other reads
and return -EINTR even for SA_RESTARTing signals. IOW:
I think -ERESTARTSYS here would be more correct than -ERESTARTNOHAND.

If -ERESTARTNOHAND is really what inotify people want, they need to
add a comment about it.

--
vda


\
 
 \ /
  Last update: 2012-02-10 17:23    [W:0.034 / U:7.884 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site