lkml.org 
[lkml]   [2007]   [Nov]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: Error returns not handled correctly by sysfs.c:subsys_attr_store()
    From
    Date
    On Wed, 2007-11-28 at 16:42 +0900, Tejun Heo wrote:
    > Greg KH wrote:
    > > On Mon, Nov 26, 2007 at 08:31:16PM -0800, Andrew Morton wrote:
    > >> On Wed, 21 Nov 2007 15:16:59 -0700 Andrew Patterson <andrew.patterson@hp.com> wrote:
    > >>
    > >>> The buf in fs/sysfs.c:subsys_attr_store() does not seem to be updated
    > >>> correctly when returning a negative value (indicating that an error
    > >>> condition has occurred) is returned. If a negative value is returned,
    > >>> the next subsequent call to subsys_attr_store will have the contents of
    > >>> buf appended to the previous call.
    > >> subsys_attr_store() gets deleted by
    > >> http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/gregkh-01-driver/kset-kill-subsys-attr.patch
    > >>
    > >> So maybe we will soon accidentally fix whatever-this-is? Or maybe we will
    > >> faithfully maintain it.
    > >
    > > Yes, subsys attributes go away, but this is showing a bug in the sysfs
    > > core with attributes, not in the "middle" layers of attributes.
    > >
    > > I bounced the original bug report to Tejun, who has been changing the
    > > logic around this area to see if he sees anything that might be
    > > different now.
    > >
    > > Tejun?
    >
    > Weird, the problem is not reproducible here.
    >
    > # echo a > allow_restart
    > -bash: echo: write error: Invalid argument
    > [ 437.518024] buf_ptr = 0xffff810005e20000, buf = x
    > [ 437.518027] , count = 2
    > # echo b > allow_restart
    > -bash: echo: write error: Invalid argument
    > [ 438.972973] buf_ptr = 0xffff81001be6f000, buf = y
    > [ 438.972976] , count = 2
    > # echo c > allow_restart
    > -bash: echo: write error: Invalid argument
    > [ 440.539747] buf_ptr = 0xffff81001d4ba000, buf = z
    > [ 440.539750] , count = 2
    >
    > Which is expected. On each open, sysfs_buffer is allocated with kzalloc
    > and the buffer is freed on close, so I don't see how it can happen.
    > Behavior for multiple write can be considered peculiar in that ppos is
    > essentially ignored and each write is passed just like brand new write
    > to ->store method but this too is the expected behavior.
    >
    > # (echo a; echo b; echo c) > allow_restart
    > [ 765.257132] buf_ptr = 0xffff81001be4f000, buf = a
    > [ 765.257135] , count = 2
    > [ 765.285474] buf_ptr = 0xffff81001be4f000, buf = b
    > [ 765.285484] , count = 2
    > [ 765.314002] buf_ptr = 0xffff81001be4f000, buf = c
    > [ 765.314004] , count = 2
    > -bash: echo: write error: Invalid argument
    > -bash: echo: write error: Invalid argument
    > -bash: echo: write error: Invalid argument
    >
    > Andrew Petterson, can you please build 2.6.24-rc3 from clean source tree
    > and retry?
    >

    I tried with clean 2.6.24-rc3 and get the same bad behavior. This is on
    an ia64 box, so maybe that is an issue. I can try on an x86 box as well.
    Oh, one other thing. I tried a "uname -r" to make sure I had the
    correct kernel booted and got:

    # uname -r
    2.6.24-rc3
    x
    y
    z
    #

    Andrew
    --
    Andrew Patterson
    Hewlett-Packard

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-11-28 20:35    [W:4.276 / U:0.080 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site