[lkml]   [2003]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: The disappearing sys_call_table export.
    On Thursday 08 May 2003 10:29, Terje Malmedal wrote:
    > [Christoph Hellwig]
    > >> The only problem I can see is that different modules overloading the
    > >> same function needs to be unloaded in the correct order. Is this the
    > >> only reason for removing it, or am I missing something?
    > >
    > > it's racy - and it doesn't work on half of the arches added over the
    > > last years.
    > Would you be so kind as to explain exactly what is racy? Just
    > asserting that it is does not help me understand anything.

    Look at this:

    [1]int init_module(void)
    [3] orig_fsync=sys_call_table[SYS_fsync];
    [4] sys_call_table[SYS_fsync]=hacked_fsync;
    [5] return 0;

    Unless there is a LOCK on sys_call_table[SYS_fsync] another CPU could
    replace the pointer between lines 3 and 4. At that point line 4 would
    destroy the existing entry.. or destroy it when the original is restored,
    and would NOT be restoring the one insterted.
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:35    [W:0.019 / U:1.656 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site