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    SubjectRe: Regression in next with ext4 oops
    * Tony Lindgren <tony@atomide.com> [161004 12:17]:
    > Hi,
    >
    > * Al Viro <viro@ZenIV.linux.org.uk> [161004 08:00]:
    > > On Tue, Oct 04, 2016 at 10:02:31AM -0400, Theodore Ts'o wrote:
    > > > On Tue, Oct 04, 2016 at 11:00:41AM +0200, Jan Kara wrote:
    > > > > Never seen this but I suspect it is a fallout from Al's directory locking
    > > > > changes. In particular ext4_htree_fill_tree() builds rb-tree of found
    > > > > directory entries in file->private_data (and generally modifies the
    > > > > structure stored there) but after Al's changes we don't have exclusive
    > > > > access to struct file if I'm right so if two processes end up calling
    > > > > getdents() for the same 'struct file' we are doomed.
    > > >
    > > > I haven't seen it either, and I've been doing a lot of testing on the
    > > > ext4 test branch. So I'm guessing Tony has the only reliable repro
    > > > for the problem at the moment. That being said, it shouldn't be that
    > > > hard to create a test case for this and add it to xfstests.
    > > >
    > > > I'm pretty sure Jan is right about this, though, but it would be great
    > > > to a get a quick confirmation from Tony if at all possible.
    > >
    > > Jan is wrong - we do have per-struct-file serialization for getdents()
    > > et.al. It might be a race between getdents() on *different* struct
    > > file for the same directory, but ->private_data is not a problem.
    >
    > OK found the guilty person after git bisect and that's me.
    >
    > Git bisect points to commit d776fc86b82f ("wlcore: sdio: Populate config
    > firmware data"), so adding Kalle to Cc.
    >
    > Looks like update-initramfs does rmmod of wlcore_sdio and that triggers
    > some issue with the wlcore driver or with SDIO/MMC. Or maybe it's a memory
    > corruption issue. I don't know yet exactly what's going on here yet but
    > I plan to find out after some lunch.

    And the patch below seems to fix the issue as the driver is now
    using devm_kzalloc. Will do some more testing and then will post
    a proper patch. The same issue might be there for SPI glue also.

    Regards,

    Tony

    8< -----------------
    --- a/drivers/net/wireless/ti/wlcore/sdio.c
    +++ b/drivers/net/wireless/ti/wlcore/sdio.c
    @@ -391,7 +391,6 @@ static void wl1271_remove(struct sdio_func *func)
    pm_runtime_get_noresume(&func->dev);

    platform_device_unregister(glue->core);
    - kfree(glue);
    }

    #ifdef CONFIG_PM
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