01 Nov, 2011

1 commit


25 Nov, 2010

1 commit


10 Sep, 2010

1 commit


01 Sep, 2010

1 commit

  • The same expression is tested twice and the result is the same each time.

    The sematic match that finds this problem is as follows:
    (http://coccinelle.lip6.fr/)

    //
    @expression@
    expression E;
    @@

    (
    * E
    || ... || E
    |
    * E
    && ... && E
    )
    //

    Signed-off-by: Julia Lawall
    Signed-off-by: John W. Linville

    Julia Lawall
     

31 Aug, 2010

1 commit

  • Wireless extensions have an unfortunate, undocumented
    requirement which requires drivers to always fill
    iwp->length when returning a successful status. When
    a driver doesn't do this, it leads to a kernel heap
    content leak when userspace offers a larger buffer
    than would have been necessary.

    Arguably, this is a driver bug, as it should, if it
    returns 0, fill iwp->length, even if it separately
    indicated that the buffer contents was not valid.

    However, we can also at least avoid the memory content
    leak if the driver doesn't do this by setting the iwp
    length to max_tokens, which then reflects how big the
    buffer is that the driver may fill, regardless of how
    big the userspace buffer is.

    To illustrate the point, this patch also fixes a
    corresponding cfg80211 bug (since this requirement
    isn't documented nor was ever pointed out by anyone
    during code review, I don't trust all drivers nor
    all cfg80211 handlers to implement it correctly).

    Cc: stable@kernel.org [all the way back]
    Signed-off-by: Johannes Berg
    Signed-off-by: John W. Linville

    Johannes Berg
     

12 Apr, 2010

1 commit


30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

24 Mar, 2010

2 commits


05 Dec, 2009

2 commits


30 Nov, 2009

1 commit


08 Oct, 2009

1 commit

  • Refactor wext to
    * split out iwpriv handling
    * split out iwspy handling
    * split out procfs support
    * allow cfg80211 to have wireless extensions compat code
    w/o CONFIG_WIRELESS_EXT

    After this, drivers need to
    - select WIRELESS_EXT - for wext support
    - select WEXT_PRIV - for iwpriv support
    - select WEXT_SPY - for iwspy support

    except cfg80211 -- which gets new hooks in wext-core.c
    and can then get wext handlers without CONFIG_WIRELESS_EXT.

    Wireless extensions procfs support is auto-selected
    based on PROC_FS and anything that requires the wext core
    (i.e. WIRELESS_EXT or CFG80211_WEXT).

    Signed-off-by: Johannes Berg
    Signed-off-by: John W. Linville

    Johannes Berg